J. H . Under'S Ore N[ode,m /Vlei-hods Of Highway MODERN METHODS OF HIGHWAY CONSTRUCTION BY JOHN HENNING ANDERSON B. S., University of Illinois, 1914 THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of CIVIL ENGINEER IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1921 \ ¥ ■* UNIVERSITY OF ILLINOIS \V~L\ THE GRADUATE SCHOOL March 26 , 19? 1 I HEREBY RECOMMEND THAT THE THESIS PREPARED BY JOHN HMNING ANDERSON ENTITLED _ MODERN METHODS OF HIGHWAY .CONSTRUCTION. BE ACCEPTED AS FULFILLING THIS PART ON THE REQUIREMENTS FOR THE PROFESSIONAL DEGREE OF -....CIVIL ENGINEER. - Head of Department of Civil Engine sring , Recommendation concurred in : Committee 4 -,45 j Digitized by the Internet Archive in 2016 https://archive.org/details/modernmethodsofhOOande TAB IE OP CONTENTS CHAPTER PAGE I. THE PROBLEM OP HIGHWAY CONSTRUCTION 1 II. METHODS OF HIGHWAY CONSTRUCTION 3 III. RATE OF CONSTRUCTION 13 IV. THE APPLICATION OF LIGHT RAILWAY TO HIGHWAY CONSTRUCTION . 20 V. TYPES OF LIGHT RAILWAY PLANT 31 VI. GRADES, SPEED AND SIZE OF TRAINS 37 VII. TRAIN SCHEDULES AND LOCATION OF SIDINGS 48 VIII. PLAN OF OPERATION 51 IX. HAULAGE EQUIPMENT REQUIRED 58 X. MATERIAL UNLOADING AND PROPORTIONING YARD 71 XI. PERSONNEL REQUIRED 90 XII. COST OF OPERATION . 98 XIII. THE ADVANTAGES AND ECONOMIES OF LIGHT RAILWAY HAULAGE . . Ill XIV. THE MINIMUM SIZE OF JOB JUSTIFYING A LIGHT RAILWAY PLANT. . 118 XV. PRESENT TENDENCIES IN HIGHWAY CONSTRUCTION 123 APPENDIX COMPARISON OF FABRICATED TRACK WITH WOODEN TIE TRACK ITEMS ENTERING INTO COST OF HIGHWAY CONSTRUCTION A GUIDE TO ESTIMATING CONSTRUCTION EQUIPMENT EXPENSE DRAWINGS OF MATERIAL TUNNEL DRAWINGS OF 200 CUBIC YARD STORAGE BIN DRAWINGS OF TYPICAL STEEL BATCH BOXES DRAWING AND SPECIFICATION SHEET OF TYPICAL PUMP CLEARANCE DIAGRAM OF TYPICAL 14-E PAVER DRAWING AND SPECIFICATIONS OF TYPICAL BATCH BOX CAR ILLUSTRATIONS OF DIRECT CHARGING OF PAVER, CITY STREET CONSTRUCTION SPECIFICATION SHEET OF TYPICAL 6 TON LOCOMOTIVE INSTRUCTIONS FOR USING SUBGRADER BULLETIN ON STEEL FORMS, THE LAKEWOOD ENGINEERING COMPANY BULLETIN ON ROAD PLANT, THE LAKEWOOD ENGINEERING COMPANY LIST OF ILLUSTRATIONS PAGE CHARGING MIXER BY HAND 3 WASTE OF MATERIAL DUE TO DUMPING ON SUBGRADE .... 4 WASTE MATERIAL ON SHOULDER OF ROAD 4 CHARGING MIXER WITH BELT CONVEYOR 5 PORTABLE BUCKET LOADER HANDLING MATERIAL FROM SUBGRADE . 5 DIRECT CHARGING OF MIXER BY MEANS OF LIGHT RAILWAY . . 6 MACHINE TRIMMING OF THE SUB GRADE 7 CHARGING MIXER DIRECT FROM TRUCK ....... 8 MOTOR TRUCKS HAULING MIXED CONCRETE 8 LIGHT RAILWAY HAULING MIXED CONCRETE 9 LAKEWOOD ROAD FINISHING MACHINE 10 LAKEWOOD SUB GRADER 11 EFFECT OF HEAVY ROLLING STOCK ON LIGHT TRACK .... 20 V-BODY CARS CHARGING SIDE LOADING PAVING MIXER ... 21 DERAILMENT RESULTING FROM POOR HIACK AND EQUIPMENT . . 21 OLD STYLE TRACK OF INADEQUATE CAPACITY 22 WOODEN TIE TRACK 23 SOIL FLOW CAUSED BY OPEN END TIES 23 PLANKS UNDER TRACK NECESSITATED BY INADEQUATE TIES . . 24 PRESSED STEEL TIE TYPE OF TRACK 25 LAYING LIGHT RAILWAY ffiACK 26 WHITCOMB 6 TON GASOLENE LOCOMOTIVE 26 LIMA 10 TON, DOUBLE TRUCK STEAM LOCOMOTIVE .... 27 PLYMOUTH 6 TON GASOLENE LOCOMOTIVE 27 BATCH BOX SYSTEM OF LIGHT RAILWAY HAULAGE .... 28 DOUBLE TRUCK GENERAL UTILITY PLATFORM CAR .... 29 BATCH BOXES CARRIED ON MOTOR TRUCKS 32 HAULING MATERIAL OVER CURED CONCRETE, COMBINED SYSTEM . 33 TRANSFERRING BATCH BOXES FROM TRUCK TO CARS .... 33 LIGHT RAILWAY CROSSING HINGED HORIZONTALLY .... 35 LIGHT RAILWAY CROSSING HINGED VERTICALLY 35 COUNTERBALANCED LIGHT RAILWAY CROSSING HINGED VERTICALLY . 36 TWENTY-FIVE CAR TRAIN IN ARIZONA 43 THREE CAR TRAIN ON 8.2 PER CENT GRADE IN PENNSYLVANIA . 43 BOOSTER LOCOMOTIVE METHOD OF NEGOTIATING STEEP GRADE ♦ . 44 MOTOR TRUCKS HAULING TRAIN UP STEEP GRADE .... 45 LOCOMOTIVE ATTACHED TO TRAIN AT MIXER 59 SWITCHING OARS WITH A HORSE 60 SWITCHING CARS BY HAND 60 PASSING SIDING NEAR MIXER 61 GENERAL UTILITY PLATFORM CAR 64 BATCH BOX HAULAGE ’WITH 3- i/2 TON TRUCK 65 LOADING TRUCK, BATCH BOX HAULAGE SYSTEM 66 * LIST OF ILLUSTRATIONS PAGE TRANSFERRING BATCH BOXES FROM TRUCK TO CARS .... 66 PORTABLE DERRICK FOR TRANSFERRING BATCH BOXES ... 66 LOCOMOTIVE AT TRANSFER POINT 68 TRAIN APPROACHING MIXER, COMBINED SYSTEM .... 68 PORTABLE BIN AT TRANSFER POINT 69 TRUCK CHASSIS EQUIPPED WITH BATCH BOX FRAME .... 69 PORTAL VIEW OF MATERIAL TUNNEL 73 SIDS VIEW OF MATERIAL TUNNEL 73 LONG MATERIAL STORAGE PILE 75 MOVABLE BIN REHANDLING PLANT 76 LIGHT RAILWAY TRACK IN CENTER OF MOVABLE BIN TRACK . . 77 SMALL STATIONARY BIN REHANDLING PLANT 78 SMALL MATERIAL DUMPING TRESTLE 78 TRESTLE SYSTEM OF UNLOADING MATERIAL 79 STOCK PILE AND BIN METHOD OF HANDLING MATERIAL ... 80 LARGE MATERIAL STORAGE BIN 81 TUNNELS BENEATH PILES STORED BY DERRICK 81 THE SUNBURY UNLOADER 82 BIN AND BUCKET ELEVATOR SYSTEM 83 METHOD OF HANDLING BAGGED CEMENT 83 BULK CEMENT BIN BETWEEN SAND AND STONE BINS . . . .84 HANDLING BULK CEMENT BY MOTOR TRUCK 85 VOLUMETRIC METHOD OF MEASURING BULK CEMENT .... 87 BULK CEMENT WEIGHING DEVICE 88 MOVABLE MATERIAL HOPPERS, ONE LOAD CAPACITY .... 90 DIRECT CHARGING OF MIXER WITH 5 TON TRUCK .... 93 FORD TRUCKS WITH SPECIAL DUMP BODY 93 DERRICK ON WAGON FOR TRANSFERRING BATCH BOXES ... 94 MACHINE TRIMMING OF THE SUBGRADE 95 BATCH BOX CHARGING SYST3M Ill UNOBSTRUCTED SUBGRADE PERMITS MACHINE TRIMMING . • .112 RE TRIMMING SUBGRADE DUE TO HtUCK HAULAGE . . . .113 RUTTED SUB GRADE DUE TO TRUCK HAULAGE 113 TRIMMING SUBGRADE BY HAND 114 MACHINE TRIMMED SUBGRADE 115 LOST MATERIAL RESULTING FROM DUMPING ON GROUND . . .116 LIGHT RAILWAY HAULAGE ELIMINATES HEAVY LABOR . . .117 BURTON 6 TON LOCOMOTIVE HAULING 8 CAR TRAIN . . . .120 1 MODEM METHODS OF HIGHWAY CONSTRUCTION CHAPTER I. THE PROBLEM OF HIGHWAY CONSTRUCTION. The highway system of the United States consists of some 2,250,000 miles of public road, or approximately two-thirds mile of road per square mile of area. The improvement of this enormous system, sufficient in extent to girdle the globe 100 times, presents a problem which in many ways is the greatest that has ever confronted a people for solution. Competent authorities have estimated, however, that the improvement of 20 per oent of the total mileage will provide a trunk line or primary system, which will carry 90 per cent of the traffic. The improvement of this primary system, consisting of some 450,000 miles of road, or 1 mile of road for every 7 square miles of area, is, therefore, our first object- ive* The magnitude of the highway problem can perhaps be best realized by comparison with our railroad system, to the development of -which we have devoted same 70 years. The primaiy highway system alone exceeds the mileage of all trunk and branch railroad lines by some 40 per cent* The cost of the heavy type of construction which modern traffic makes necessary on the primary system will at least equal, and in many oases exceed, the cost of the railroads at the time of their construction* In both cost and mileage, therefore, our highway system ex- ceeds the railroad system, considering merely that portion, some 20 per cent, herein designated as the primary system* While it is inpossible to estimate the length of time that will be re- quired to complete our highway system, it is no doubt safe to say that a period of time considerably shorter than 70 years will be allowed by an impatient public for the completion of at least the 450,000 miles of road comprising the primary system. The value and necessity of good roads is at last fully realized, and ample funds have been provided by the publio. The demand is now for a comprehensive system in the shortest possible time* It has been estimated that approximately $1,000,000,000 are available for highway construction in 1921, while about two-thirds of this amount was avail- able in 1920. The limiting factor to quantity product ion of roads to date has been the supply of raw materials, and whether or not the material supply will be adequate to permit construction at a rate commensurate with the funds available is problematical. Assuming, however, that the material situation will be properly adjusted and that funds available will be maintained at the rate for 1921, approx- imately 20 years will be required to complete the primary system at an average cost of $40,000 per mile. To complete the primaiy system in 20 years will entail construction at the rate of 24,000 miles per year. This rate of construction of trunk line highway is considerably greater than has been attained to date, so even allowing for a big increase in the rate of production, due to improved methods, 2 it seems that an allowance of 20 years for completing the primary system is about the minimum that good judgment dictates at the present time. Simultaneously with the construction of the primary system, a considerable amount of construction can be carried on in the cheaper types of road suitable for the secondary system. It i6 not the province of this thesis to deal with the merits of any particular kind of road surfacing. Suffice it to say that the consensus of opin- ion among leading highway engineers at the present time is that roads with a concrete wearing surface, or a concrete base to support some other type of wearing surface, are necessaiy to withstand the effects of the heavy traffic which our trunk line highways will be subjected to. Inasmuch as the construction of this type of road is the most difficult and costly, this thesis will deal only with methods of construction of so-called permanent roads. The methods described in this thesis will apply to any type of road in which concrete is used either as a wearing surface or a base. Modern heavy traffic, consisting of a vast and ever increasing number of motor trucks, requires much heavier construction and closer attention to de- tails, than was considered necessary only a few years ago. Heavier construction naturally calls for the use of a much greater quantity of material than formerly, and the work of handling this material is consequently increased. This has led to the extensive use of machinery to replace hand methods, not only on account of greater economy and efficiency but also due to the necessity of increasing output. At the present time we are undertaking the biggest road building program known in history, in spite of the fact that, until the winter of 1920-21, the country was suffering from an acute labor shortage and widespread unrest . No doubt this labor shortage will again make its appearance at the expiration of the present temporary period of depression. In order to overcome labor shortage, extensive use of machinery has been resorted to in highway construction. It is becoming increasingly difficult to secure labor to perform heavy manual work, and this again has led to the extensive substitution of machinery for hand methods. It has been the experience of many contractors, that labor turnover has been greatly reduced by the elimination of heavy manual labor thru the introduction of machinery. Mechanical methods also lead to the development of a higher type of labor than do hand methods. At the present tiros highway construction is just emerging from the "rule-of-thumb", "hit-or-miss" stage, and for the first time scientific methods and thoro organization are being given proper consideration. Until quite re- cently road building has been considered a small man's game, and even now some engineers adhere to this opinion. The demand for good roads is so great, however, that it is inpossible to supply it by the old methods of operation. Road building is no longer a small man's game, and it is now attracting some of the largest contracting organizations in the country. Contracts for $1,000,000 worth of work and up are now quite common. An illustration of the present trend in highway construction is afforded by Maricopa County, Arizona, where a contract for 288 miles of concrete road was awarded to one contractor in 1920. Due to the fact that the work is spread out over such a great area and the concrete mixers are frequently many miles from the material yard, highway construction is essentially a transportation problem. Greater refinement is necessary in highway construction than in most any other class of work. \ 3 CHAPTER II. METHODS OF HIGHWAY CONSTRUCTION Until 2 years ago the general method of constructing a road in which concrete was used as a wearing surface or a base, has been to haul the aggregates from the material yard and dump them on the subgrade in windrows. The aggregates were then loaded into wheelbarrows by means of shovels, and wheeled to the charg- ing skip of the mixer. This method naturally required a large number of wheelers and shovelers, the average size wheelbarrow load approximating 3 cubic feet. To load materials for a 4-bag batoh of concrete of the proportions generally used, required a wheeling and shoveling crew of at least 16 men. This work was hard to perform, and the labor turnover in the charging crew was generally considerable. Occasionally a few hundred feet of 24 -inch gavge track and a few dump oars were used, loading the cars by hand and pushing them to the skip of the mixer. CHARGING LEXER BY HAND One of the serious objections to the method of dumping aggregates on the subgrade is the cutting up of the subgrade by the wheels of the vehicles, particularly for a considerable time after a rain. Not only is the subgrade badly cut up, but serious delay is frequently incurred due to the inability of vehicles to operate over the subgrade for a number of days after a rain. In certain clay soils the delay caused by a rain will sometimes amount to a week or more. The seriousness of this lost time during the construction season is obvious. Another serious objection to the dumping of aggregates on the subgrade is the dirt which is generally mixed with the material. The effect of this for- eign matter on the quality of the pavement, particularly when a concrete wearing surface is employed, is apparent. Not only is dirt mixed with the aggregate but a considerable amount of aggregate is lost to the ccnbractor due to rejection by the inspector because of the dirt mixed with it, and the grinding of the aggregate into the subgrade by the wheels of the vehicles employed in hauling it. A number of states now prohibit the dumping of aggregate on the subgrade. . To distrioute aggregate on the suograde in proper quantity is exceed- ingly difficult. If insufficient material is placed it is very diffi- cult to replenish the supply because of the oostruction formed by the windrows of material on the subgrade. A long wheelbarrow haul generally results until additional material can be brought up. If too much material is distributed, it is generally im- possible to remove the surplus with- out delaying the concrete mixer. The surplus, therefore, is almost always thrown on the shoulder where it is wasted. ’VASTS MATERIAL OK SUBGRADE. Dumping the aggregate on the sub- grade precludes the use of a subgrade machine for trimming the subgrade, necessitating expensive and inaccurate hand trimming. The practice of dump- ing aggregate on the suograde also en- tails (i considerable amount of retrim- ming, due to the ruts formed by the vehicles. WASTE MATERIAL OK SHOULDER. a w 5 Sometimes a portable belt conveyor is used in charging the concrete mixer. A typical machine of this class is that manufactured by the Koehring Machine Company, of Milwaukee, Wisconsin. This machine is equipped with a number of hoppers into which sand and stone is shoveled. Each hopper is of predetermined capacity, and discharges onto the belt by means of a door in the bottom. A con- veyor belt of this type will eliminate wheelers but will require the same number of 8hovelers,plus an additional man or two to clear the way for moving the machine. A gasolene engine furnishes the power for the operation of the belt, and an oper- ator must be detailed to take care of the engine. This method of construction does not eliminate dirt in the aggregates, nor waste due to dumping on the sub- grade. The obstruction formed by the windrows of material likewise precludes mechanical trimming of the subgrade. While the loading belt has been used to a considerable extent during the past two years, the consensus of opinion among contractors is that this method is not economical. Naturally this method of con- struction cannot be used where specifications prohibit dumping material on the subgrade, or permit it to be dumped only in piles 1,000 feet or so apart. PORTABLE BUCKET LOADER HANDLING MATERIAL FROM SUBGRADE CHARGING MIXER WITH BELT CONVEY® d eldstrocr s s& axiict lo enixiosm I >03 iW ,ee?lJxsv;IiM lo f extol a fins Jbxiea riolriw o Jlecf exii olxxo aegiario^ii) .«• ei-sxxifnile II iw eq^J slxil \ jvrt 10 xtGn iBiioI 3 ibbs as suLq,s .i icl isvvoq oil 3 sodslsrxifi saiga© $as exi 3 ‘io eiso e>Js3 od belisieb ed •ic a .39^x3§9i^je ©xtt ni Six!) etsnlmile 'O ihnivJ &ti$ Y,d b&miol noi I oi;i J arf o silT r ixlW .sJbBigcfoa erU Io ^hIotuIiI Iso. owj J&sq 9rii gniiaJb iasixe ©IcTsie* ~in si Jbcxidsra aixitf io/ltf si aioJosx '9q3 eisrfw Jbeax; ecf Ioxuxbo noi^o. -Tx/Jb 9 gT oJ ii Sxrrrteq io f 9£)£igv 6 Sometimes a small amount of light railway track: is used to haul material from piles on the subgrade one-half mile or so apart* To load the hatch boxes a portable bucket loader is frequently employed, as shorn in the foregoing illustra- tion. A power soraper is used to scrape material up to the bucket loader, as shown. Power for operating this scraper is obtained from the engine driving the bucket loader. This method is more economical than the method of dumping material in long windrows, as there is less chance for loss of material. The same objec- tions due to cutting up the subgrade, delay from rain, etc. apply to this method with almost equal force as those which apply to the windrow method. When teams, motor trucks, or tractors are used for hauling material it is necessary to begin laying concrete at the most distant point from the material yard, or at some other point between the material yard and the far end of the road provided side roads are available. This is due to the impossibility of hauling past the uncured ooncrete, as there is very seldom sufficient room on the shoulder of the road for the operation of teams, trucks, or tractors. When this method of haulage is employed, therefore, it is generally necessary to delay placing concrete until the grading between the material yard and the far end of the road is complete At times this delay might be reduced by hauling material thru the grading opera- tions, but the difficulty, and at times impossibility, of so doing in case of deep outs or fills or the building of the road in a new location is apparent. Good side roads are difficult to find, and even whan they do exist the length of haul is generally increased quite materially. The effect of hauling material over the finished grade, especially in case of wet weather, needs no comment. Not only is the placing of concrete delayed when either of the foregoing methods of haulage is employed, but when concreting is finally started the most expensive part of the work, the long haul part, is done first. This results in small payments from the state, at a time when working capital is most badly needed. The untrained organiza- tion is also required to do the most difficult part of the work first. The latest and most modern method of building roads on a large scale, is by means of the li^ht railway method. In this method a light railway is employed to haul material in batch boxes from the material yard directly to the mixer. Two batch boxes are generally oarried on each car, each box containing complete ma- terials for a batch of proper size for the mixer. On arrival at the mixer each box is picked up by means of a small derrick attached to the mixer, and the batch boxes dumped directly into the skip. With this system materials never touch the subgrade at all. DIRECT CHARGING OF MIXER BY MEANS OF LIGHT BAIL?/ AT. . . * - ♦ 7 if In place of the wheeling and shoveling gang of 16 or more men necessary in the old method of 'building roads, only 2 or 3 men are needed to charge the mixer by means of the hatch hox and light railway system. The resulting economy of 13 or 14 men, at the present high price of labor, amounts to a large sum in the course of a season. Due to the fact that aggregates are not dumped on the subgrade, loss of material and the picking up of dirt is eliminated. Minimum de- lay from rain i6 insured, while it is possible to start work earlier in the spring than if a method of construction is used which depends upon haulage over earth roads. The unobstructed subgrade permits machine trimming to be performed, thus reducing the cost of trimming and eliminating loss due to the placing of extra concrete resulting from inaccurate subgrade. MACHINE TRIMMING OF THE SUBGRADE Light railway haulage permits the laying of concrete to begin at the point nearest the material yard, inasmuch as hauling oan be performed past the uncured concrete on the shoulder of the road. The laying of concrete oan begin as soon as a few hundred feet of subgrade have been prepared, and can follow inmediately behind the grading operations without interference. This eliminates the delay that generally occurs in placing concrete when a system of haulage is used which cannot operate past the uncured concrete. Not only oan the placing of concrete and the operation of grading be carried on simultaneously, but the most profitable portion of the conorete, the short haul portion, is done first. A large payment from the State early in the life of the job is thus insured, provid- ing the working capital generally so badly needed at this time. Furthermore, by the time the long haul portion of the job is reached, the organization is exper- ienced and the track is well bedded. Another method of construction which has come into quite general use during the past 2 years, is to haul properly proportioned batches in motor trucks and dump directly into the skip of the mixer. Dump body trucks of 3 and 5 ton capacity, with the bodies partitioned off so as to form compartments for a number of batches, are sometimes used. The difficulty of handling these heavy units on the subgrade, particularly of turning them, and their destructive effect on the subgrade, has led to the use of light trucks, such as the Ford. These light trucks are equipped with oversize tires, and with special dump bodies arranged to dump to the rear. A number of patented types of dump bodies are on the market at the present time, among than the Lee body and the Hanson body. The Ford truck 8 possesses the advantage of being easily turned by means of a light turntable, and of not cutting up the subgrade as badly as the larger truck. The disadvantage of the light truck system over the heavy truck system is the larger number of units and drivers required, as well as the rapid depreciation of the light machines* The objection to all truck systems is the delay caused by wet subgrade, the cut- ting up of the subgrade,and the fact that the placing of concrete must begin at the point farthest from the material yard* As mentioned in a previous paragraph this results in considerable delay, and in minimum payments from the State just at a time when money is most badly needed. CHARGING MIXER DIRECT FROM TRUCK MOTOR TRUCKS HAULING MIXED CONCRETE In some parts of the country the central mixing plant method of building roads has been used to a certain extent. When this method is employed, the mixed concrete is generally hauled out to the road by neans of motor trucks, as shown in 9 the above photograph. The trucks shown in the photograph are 5 ton units, hauling about 2 cubic yards of concrete per trip in a special dump body. The difficulty of removing the concrete, and the planks on the subgrade necessary to prevent ratting, are clearly shown. Considerable segregation of the concrete occurs, especially if the consistency is wet. The use of a mechanical finishing machine, shown in the lower right hand corner of the photcgraph, permits a dryer consist- ency to be used, and obviates to a certain extent the objections to the central mixing plant nethod. In the central mixing plait method there is always the danger that too great a length of time will elapse between the mixing of the con- crete and the plaoing of it on the road. With this method it is also necessary to delay the placing of concrete until a good deal of the grading has been com- pleted, ani to begin the placing of concrete at a point farthest from the material yard. The possibility of delay, due to wet subgrade and the cutting up of the subgrade by the motor trucks, is another objection to the central mixing plant plan. The central mixing plant method of construction has been used in a few instances with the light railway system of batch box haulage. The mixed concrete has been discharged directly into batch boxes of the steel, tip-over type, and hauled to the road in the regular manner. A crane picked up the loaded boxes frcjn the cars and swung them over the subgrade where they were dumped by 2 men. In order to remove the packed concrete from the corners, a small air compressor was installed on the crane. The photograph below shows the method of dislodging concrete from the corners of the box by means of thfr compressed air, method. A pressure of 50 to 60 pounds per square inch has been found sufficient. The same objection to the segregation of the concrete and the possibility of too long a time elapsing between the mixing and finishing operations, can be brought against the central mixing plant when light railway haulage is enployed as when motor truck haulage is used. LIGHT RAILWAY HAULING MIXED COT CRETE In the opinion of many oontraotors, aside from reliability of operation due to greater independence of weather conditions and the saving in labor, the biggest advantage of light railway haulage is the possibility of carrying on con- creting and grading operations simultaneously. This insures a large payment early in the life of the job, which provides much needed working capital. 10 Until the summer of 1919 hand methods were universally enployed in striking off and finishing concrete road, and concrete base for other types of pavement. At that time the first successful mechanical finishing machine, that of The Lakewood Engineering Company, of Cleveland, Ohio, was introduced, and at the present time between 400 and 500 of these machines are in use. This machine not only strikes off the concrete, but subjeots it to an intensive tamping action. Dryer mixtures oan thus be used, resulting in denser and stronger concrete accord- ing to the researches of Professor Duff Abrams, of Lewis Institute, Chioago. Hot only does the mechanical finishing machine produce a better pavement but it saves the labor of 2 or 3 men for the contractor. A number of State Highway Departments at the present time either specify machine finishing for concrete roads, or offer special concessions to the contractor to induce him to use a finishing machine. The finishing machine shown in the foregoing illustration is well adapted to the construction of brick pavements, especially of the monolithic type. It is employed to. strike off and tamp the concrete base and to tamp the brick, thus pro- ducing a much smoother job than is possible by hand methods. In speaking of the use of the finishing machine in monolithic brick road construct ion in Engineering Hews-Record for January 6, 1921, Mr, W. M. Watson, State Highway Engineer of Kansas, states as follows: I "At the beginning of the work the base was poured at a stiff con- sistency and sbruok off by the Parrish type of multiple steel templet, using a 3/l6" dry sand-cement bed. The brick were laid directly on the sand-cement bed before the base attained its initial set. The gravel aggregate, containing very little coarse material, produced a concrete with which it was difficult to obtain satisfactory results. When mixed sufficiently dry to permit the other operations it contained too little water properly to saturate the dry cushion, with a consequent separation between the base and brick surface. When made with enough water to give the dry cushion the proper amount of water, due to the absence of coarse material, the concrete had little stability, rendering the operations of rolling and grouting exceedingly difficult and .. 11 making it almost impossible to secure a smooth surface. This trouble has been overcome by the use of a mechanical tamp ing machine operated directly on the base, and by eliminating the sand-cement cushion. A marked improvement is noted by reason of this change, not only in the surface of the pavement but in the adhesion as well. Not only does mortar tamped to the surface, firmly adhere to the brick, but from l/4" to l/2” of mortar squeezes up be- tween the bricks, giving greater assured resistance to the sliding of the brick along the base, due to difference in coefficient of expansion. A much denser concrete in the base is also assured.” Complete specifications of the Lakewood finishing machine will be found in the appendix to this thesis. To secure the best results with a finishing ma- chine it is necessary to use steel forms weighing not less than 6-l/2 pounds per foot exclusive of fastenings. A machine for trimming subgrade has been developed by The Lakewood Eng- ineering Company and is now extensively used. This machine operates on the side fonns and is generally pulled by means of the road roller, as shown in the follow- ing illustration. LAKEWOOD SUBGRADER One of the most troublesome and expensive operations performed in road building is that of trimming the subgrade, aid by hand methods it is seldom possi- ble to secure a surface closer than one-fourth inch of the correct contour and elevation. With the rigid inspection characteristic of road building today, the subgrade is generally cut too low. Loss due to low subgrade is one of the most prevalent and difficult to overcome when subgrade is trinmed by hand. Machine trimming will produce a subgrade practically as accurate as the finished pavemmt. When we stop to consider that a subgrade one -fourth inch too low results in placing 75 cubic yards of oonorete per mile of 18 foot road for which no pay is received, and oonorete is worth from $15.00 to $22.00 per cubic yard, the possibility of loss from this source is apparent. Machine trinming of the subgrade not only results in greater accuracy, but in less cost than han d trimming. . 12 In the past hut little attention has been paid to the problem of in- suring a reliable and adequate water supply, in spite of the fact that the cost of a good pump is but a few per cent of the cost of the plant, whose operation depends entirely on it* Happily the importance of insuring a proper water supply is now fully realized by progressive highway contractors, many of whom are using a double unit pump* The double unit pump consists of 2 complete pumps and gaso- lene engines mounted on a truck, so arranged that either pump can be operated in- dependently of the other or both pumps together if desired* The use of a pipe line of inadequate capacity is one of the most expen- sive mistakes which a highway contractor can make, for this will off-set any pro- vision he has made for adequate pumping capacity. A pipe line not less than 2 inches in diameter should be used to furnish water for a half yard or three- quart ex yard paving mixer, wet batch rating, and a pipe line preferably of 2-l/2 inches diameter for a cubic yard mixer* Gate valves should be provided every half mile, and unions every 1,000 feet* Provision must be made for taking care of expansion and contraction in the pipe line, either by means of a patented expansion joint such as that manufactured by the C. H. & E. Manufacturing Company, of Milwaukee, Wisconsin, or by means of a home made device consisting of a short section of hose* Tees should be inserted in the pipe line approximately every 100 feet to permit attachment of the hose leading to the paving mixer. While we are considering the subject of pipe lines, it is desired to point out that a oentral mixing plant will not eliminate the necessity for employing a pipe line and pump because water must be supplied for curing the concrete* To supply water for a half yard or three-quarter yard paving mixer plant including water for sprinkling the subgrade and curing the concrete, the pump should be capable of delivering a supply of at least 30 to 40 gallons per minute at the end of the pipe line* In order to supply this amount at the end of 3 miles of new 2 inch wrought iron pipe, a pressure of about 225 pounds per square inch must be maintained at the pump in level country* We can sum up the modern method of road building briefly by stating that the tendency is to replace hand methods by machine methods wherever possible* This machinery is of a much better type than that formerly considered good enough for construction work, and the units are not selected in a haphazard fashion* The modern road building plant consists of a number of high class, properly balanced, and coordinated units, designed to operate as a whole* Boad building is rapidly- becoming a highly oxganized manufacturing "business, for after all a road builder is a manufacture assembling his raw materials into the finished product thru the medium of machinery* The business of road building is rapidly assuming the highly organized methods of the manufacturer* 13 CHAPTER III. RATE OF CONSTRUCTION The rate of construction obviously depends upon the type of road, and upon the quantity of material contained in it. This brings us to the considera- tion of a mistake frequently made in computing quantities of material, namely assuming the average thickness of a road with a crowned surface on a flat sub- grade to be the mean between the side and center thickness. If the surface of a road is a plane this assumption would be correct, but the surface is generally parabolic or cylindrical. Due to the long radius, there is practically no differ- ence in the average thickness of a road having a cylindrical or a parabolic sur- face. Assuming the surface to be parabolic, a formula can be derived for the average thickness. This formula can be expressed in terms of the mean of the side and center depths, plus one-sixth of the crown. For instance, a road 6 inches thick at the sides and 8 inches at the center on a flat subgrade has an average depth of 7-l/3 inches. In case the subgrade is crowned in a different manner from the surface of the pavement, the average thickness is equal to the mean between the side and center depths plus one-sixth of the difference between the surface and subgrade crowns. Inasmuch as an increase of l/s inch in the average depth amounts to almost 100 cubic yards of concrete per mile of 18 foot road, the seriousness of assuming the average depth as a mean between the sides and the center is apparent. A road 6 inches thick at the sides and 8 inches thick at the center on a flat subgrade has an average thickness of 7-l/3 inches, as shown in the preced- ing paragraph. On such a road 1 cubic yard of concrete will produoe 4.91 square yards of pavement. An 18 foot road of this type contains 0.407 cubic yards of concrete per lineal foot, or 2,150 cubic yards per mile. Based upon a weight of 376 pounds per barrel of cement, 3,000 pounds per cubic yard of sand, and 2,700 pounds per oubic yard of stone, the quantity of material required per mile of 18 foot concrete road of a 1-2-3 mixture, 6 inches thick at the sides and 8 inches thick at the center, is as follows: 3,762 bbls. cement or 1,118 cu.yds. sand or 1,677 cu.yds. stone or 707 tons 1,677 " 2.264 " Total 4,648 tons The rate of construction naturally depends to a certain extent upon the size of batch used in the concrete mixer, but more upon the efficiency of the organization. Practically all state highway specifications set a time limit of not less than 1 minute for mixing concrete, and this time limit is the big factor to consider in determining output. When a time limit of 1 minute is specified it is possible for a good organization to produoe 40 batches of concrete per hour with a one-half or three-quarter yard paving mixer without violating specifications Experience indicates, however, that 30 batches per hour is a good rate of opera- tion for this size of mixer, and a good organization with an adequate supply Of materials should maintain this rate. With a 1 cubic yard paving mixer it is not wise to count on more than 24 batohes per hour. It must be clearly understood that the rate of operation given in this paragraph is the actual rate which should be obtained under normal conditions, and is not inclusive of unusual delays. ♦ 14, In order to overcome the confusion which existed a few years ago with respect to the capacity of concrete mixers, the National Association of Mixer Manufacturers have adopted a standard system for designating the capacity of mixers* At the present time a system of numbers and letters is used which indicate not only the capacity of the mixer, but also the type. The numbers indicate the cubic feet of mixed concrete which a mixer can handle per batch under normal condi- tions, while the letters indicate whether the mixer is a side loader and side dis- charge machine or an end loader and end discharge machine. The side loading and side discharge machines are building mixers, while the end loading and end dis- charge machines are paving mixers. For instance, a 14-E mixer indicates a paving mixer, having a capacity of 14 cubic feet of mixed concrete per batch, while the 21-S mixer indicates a building mixer having a capacity of 21 cubic feet of con- crete per batch. The amount of dry materials required to produce a certain amount of mixed concrete, is approximately 50 per cent greater than the volume of the mixed concrete. At the present time the tendency is toward the use of larger paving mixers, for a large machine can be operated with practically no more men than a small machine. The 10-E, 14-E, and 21-E machines are the types most commonly em- ployed in highway construction at the present time. The 2F-E machine is rapidly coming into favor, however, and promises to become the most popular type within a few years. The 10-E machine is entirely too small for quantity production of roads and the manufacture of this type has now been discontinued by most manufacturers. The 14-E and 21-E sizes are employed on perhaps 95 per cent of the work today. The size of a batch of concrete is generally expressed in terms of the number of bags of cement which it contains, such as a 3 bag or 4 bag batch. Nat- urally the number of bags of cement which can be placed in one batch depends upon the capacity of the mixer, and the proportions. For instance, a 14-E mixer can be used to mix a 4 bag batch of 1-2-3 concrete, producing 15«£ cubic feet, inasmuch as all mixers are designed with a normal overload capacity. To mix a 5 bag batch of 1-2-3 concrete, amounting to 19.5 cubic feet, will require a 21-E mixer. A 28-E mixer is capable of mixing a 7 ba£ batch of this mixture. On the other hand if the concrete is to be mixed in the proportions of l-2§^5, a 14-E mixer can handle only a 3 bag batoh, etc. At a rate of 30 batches per hour, a 14-E mixer handling a 4 bag batch of 1-2-3 concrete will produce 17.4 cubic yards. At this rate the output in 10 hours would be 174 oubic yards, equivalaat to 854 square yards of concrete averaging 7-l/3 inches in thickness. Such an output is equivalent to 427 lineal feet of 18 foot road. To allow for minor delays we will call the daily output 400 feet of road of this type. In estimating the monthly output it is not wise to assume more than 20 working days per month during a normal season. At a rate of 400 feet of road per day, a 14-E mixer should produce 8,000 feet or l-l/2 miles per 20 day month. To allow further for contingencies, experience indicates that the monthly output of a 14-E mixer on the type of road we have assumed should not be taken to exceed l-l/4 miles under normal conditions. Sometimes it is wise not to count on more than 1 mile of 18 foot concrete road, having an average thickness of 7-l/3 inches, per month from a 14-E machine. These outputs are based upon normal conditions, and might be materially altered one way or the other by weather conditions, mater- ial supply, etc. Local conditions must be considered and individual judgment exercised in estimating the probable rate of construction on any job, but a good organization with an adequate supply of materials should produce the outputs mentioned in this paragraph. % 15 The amount of road produced per season depends largely upon the length of the working season, which in turn varies with climatic conditions. In the Middle West a working season of 5 or 6 months is all that can he depended upon, while in California and parts of the South the working season is frequently twice as long. With a working season of 5 or 6 months a good organization with an ade- quate supply of materials should produce from 6 to 7-jjr miles of standard 18 “foot concrete road under normal conditions with a 14-E mixer. A 21-E mixer should pro- duce from 8 to 9 miles of standard concrete road in a normal season, while a 28-E mixer should produce from 10 to 12 miles. A standard concrete road is considered to he 18 feet wide, with an average thickness of 7-l/3 inches. The output of road per working season depends upon many factors other than the capacity of the mixer, chief among whioh are the organizing ability of the contractor and the supply of raw materials. Many cases are known where a 14-E paving mixer is producing only 250 lineal feet of 18 foot concrete per 10 hour day, whereas the same type of machine working under practically the same conditions a few miles away is producing from 400 to 500 feet. It is true that during the past two years the output of road has been seriously limited by the shortage of raw material, and by erratic and inefficient railroad service. Nevertheless the biggest limiting factor in road production has always been, and still is, poor organization. Some men will take a second hand concrete mixer and a few wheel- barrows and make a success of highway construction, while others will fail even though equipped with the most modern machinery. In highway construction, as in every other human activity, the personal element enters largely into the final result s • To show the possibility of producing roads in quantity, a few examples selected at random from various sections of the country will be given: In 1919 the Bates & Bogers Construction Company, of Chicago, averaged 440 lineal feet of standard Illinois 18 foot concrete road per day for 3 weeks with a 14-E mixer in one run. On another occasion they averaged better than 460 feet per day for 10 days. These performances were given me during a conversation with a member of the firm, and undoubtedly they were duplicated or exoeeded many times. In 1920 this same firm laid as high as 490 feet of concrete road 17 feet 4 inches wide averaging 9-l/3 inches in thickness in 10 hours with a 14-E mixer for the Ohio State Highway Department, In 1920 and 1921 Twohy Brothers, of Portland, Oregon, operating on a 268 mile concrete road contract in Arizona, frequently placed 500 feet of 18 foot con- crete road of a 1-2-4 mix and 7-l/3 inch average thickness in 8 hours. A 14-E Lakewood paving mixer was used, supplied with a light railway haulage system. The photograph on page 6 shows one of the mixing plants on this job. Note the small organization required to operate this plant. Allen J. Parrish, of Paris, Illinois, in 1920, produced as high as 790 feet of standard Illinois 18 foot concrete road with a 21-E Smith paving mixer in 10 hours. His average output for 14 consecutive working days was 565 feet, while his output thruout the season averaged well over 450 feet per working day. Mr. Parish used a 5 bag batch of 1-2-3^- concrete, and in order to produce 790 feet of road in 10 hours it was necessary to maintain an output of about 40 batches per hour thruout the day. In speaking of Mr. Parrish’s accomplishment Engineering News-Record for January 6, 1921 1 states as follows: "Explanation of this continuous good progress lies in the one word managemait, which includes keeping the supply of materials constant." 16. Johnson, Drake & Piper, of Minneapolis, built an average of 590 lineal feet of 18 foot concrete road for 23 days in the month of October, 1920. The total output for the month amounted to 2.37 miles. This was accomplished by hauling out properly proportioned batches in trucks, and d imping directly into the skip of the 1 cubic yard mixer. The type of road was concrete 18 feet wide, of a 1-2-4 mixture, and an average thickness of 7-l/3 inches. Siams, Helmer, & Schaffner, of St. Paul on state road wDrk in Minnesota, have produced as much as 1,072 lineal feet of 18 foot concrete road in 10 hours. Properly proportioned batches were hauled out in batch boxes by means of light railway, and were dumped directly into a specially arranged 28-S Lakewood building mixer. This work was performed during the season of 1920. Another Minnesota firm, McCree-Moos, of St. Paul, laid 1,098 feet of 18 foot concrete road in 10 hours during the season of 1920. A central mixing plant consisting of a 1 cubic yard building mixer was used to mix the concrete, which was hauled to the road by means of motor trucks. Mr. G. P. Scharl, of Muskegon, Michigan, operating a 28-E Koehring mixer supplied by means of the light railway and batch box system, has produced 1,031 lineal feet of 18 foot concrete road in 10 hours. This road was 18 feet wide, of a l-l^-3 mixture, and an average thickness of 7-l/3 inches. Mr. Scharl' s best weekly output was somewhat over 5,000 feet, while his monthly output has run as high as 2-l/2 miles. This work was performed in 1920. The Henry W. Horst Company, of Rock Island, Illinois, operating on standard Illinois concrete road 16 and 18 feet wide near Vandalia, Illinois, dur- ing the season of 1920, frequently laid 600 feet of road in 10 hours. Mr. Horst used Ford trucks to haul properly proportioned batches and dump directly into the skip of the paving mixer. A central mixing plant was also used in conjunction with Ford trucks, and the output of each method was just about the same. James 0. Heyworth, of Chicago, in building an 18 foot concrete road for the Illinois State Highway Department , during the seasons of 1919 and 1920, fre- quently laid 500 feet in 10 hours with the light railway system. Mellon r Stuart, Nelson Company, of Chicago, operating on standard 18 foot Illinois concrete road near Desplaines, Illinois, laid from 600 to 700 feet of road in 10 hours. A li^it railway system manufactured by the Western Wheeled Scraper Company, of Aurora Illinois, was used to haul properly proportioned batches in batch boxes to the 21-E mixer. Thomas Fitzgerald, of Ashtabula, Ohio, during the season of 1919, laid 11.92 miles of monolithic brick road 16 and 18 feet wide in 92 working days for the Ohio State Highway Department, with two 14-E mixers. George Walters, of Butler, Penna. laid from 525 feet to 588 feet of 16 foot reinforced concrete road of a 1-2-3 mixture and an average thickness of 7-l/3 inches, in 10 hours. This work was performed in the summer of 1920 for the Pennsylvania State Highway Department, using a 14-E Rex mixer. The minimum time limit in Pennsylvania for mixing concrete is l-l/4 minutes. The Quinlan-Robertson Company, of Montreal, Canada, in 1920 have laid from 600 to 700 feet of standard 18 foot Pennsylvania reinforced concrete road in 10 hours. A light railway haulage system was used to haul material in batch boxes to a 28-E Koehring paver. I ♦ 17 Elder & Company, at Georgetown, Delaware, laid as high as 781 feet of 14 foot concrete road, having an average thickness of 6-l/3 inches, in 10 hours during the season of 1920. This work was performed for the Delaware State Highway Department. A 28-E Koehring mixer was used to mix the concrete, which was of 1-2-4 proportions. The Chicago Heights Coal Company, at Momence, Illinois, and the J, J. Dunnegan Construction Company, at Morrison, Illinois, have produced from 450 to 550 lineal feet of 18 foot standard Illinois concrete road in 10 hours, during the seasons of 1919 and 1920. The light railway system of haulage was used to supply 14— E Lakewood paving mixers. It is "by no means intended to convey the impression that the output of road mentioned in the preceding paragraphs was maintained every day thruout the season. They were merely mentioned to show the possibility for quantity produc- tion open to a contractor of good organizing ability, and as an answer to those who claim that from 250 to 300 feet of road per 10 hour day is all that can be expected. The fact that the records mentioned above were made during the periods of acute material and labor shortage prevailing in 1919 and 1920, is all the more reason to assume that these records will not only be frequently duplicated but greatly exceeded during the normal times which seem to be approaching. As in the case of Mr. Parrish, the explanation of the foregoing records is given by the one word management, though undoubtedly a properly balanced and coordinated road building plant was a oontributary cause. The selection of the proper road build- ing plant, however, can also be considered as coming under the head of good manage- ment • Heretofore contractors have paid but little attention to the problem of insuring an adequate supply of raw materials during the working season, by storing material during the inactive months. The general practice has been to depend more or less upon day to day delivery from the producer and the railroad. The danger of such practioe has been most forcefully presented during the acute material shortage and inefficient and erratic railroad service prevailing the past two years^ A manufacturer who undertook business without adequate preparation in the way of stock on hand, would not be considered a man of good business judgnent* A con- tractor is nothing more nor less than a manufacturer of roads, and failure on his part to adequately prepare for the construction season by storing material is no more excusable than it would be on the part of the manufacturer of any other article. State highway departments, profiting by the experience of the past two years, now realize the necessity for a contractor preparing himself for the con- struction season by storing material during the winter months. In the past the biggest handicap to this practice has been the large amount of working capital tied up. In order to overcome this handicap and induce contractors to store mat- erial during the inactive months, most states have made provision in their speci- fications for monthly payments on stored material. This should go a long way to- ward inducing contractors to store material, and a resulting decreased delqy dar- ing the construction season should mean a greater output of road. In the fall of 1919 the Lakewood Engineering Company, of Cleveland, Ohio sent letters to a large number of material producers thruout the country, asking them their opinion of winter storage of materials. Many producers replied that it would be impossible or very difficult to operate all winter, but the consensus of opinion of about 100 producers thruout the country was to the effect that they could operate at least 2 or 3 months longer than they do at present if contractors would store material during the inactive months. In the fall of 1920 the Lakewood . 18 Engineeriig Company again sent out hundreds of letters to State Highway Depart- ments, Bankers, Material Producers, Contractors and Railroad Officials on the subject of winter storage of road building material. The consensus of opinion from all classes was that winter storage is not only desirable but necessary if the production of roads is to be adequate to the demands. The progressive con- tractor, therefore, who desires to insure himself against delay during the con- struction season, should have no difficulty at the present time in financing winter storage of materials. It is realized that the storage of materials during the most severe weather in many parts of the country is very difficult, but it is almost always possible to store materials for a month or two before severe winter weather sets in and for the same length of time in the early spring before the season is sufficiently advanced to permit laying concrete. The storage of cement is much more difficult than the storage of sand or stone, because of the possibility of spoiling. Many states, however, will per- mit canent to be stored after a certain date, among them Pennsylvania which per- mits this practice after February 15th. Many contractors have suffered loss in the past due to improper storage of cement. A good discussion of this subject appeared in Engineering Hews -Record for December 2, 1920 by Mr. Blain S. Smith, General Sales Manager for the Universal Portland Cement Company, of Chicago. In this discussion Mr. Smith pointed out that not only should the cemait shed have weather tight walls, floor and roof lined with building paper, but the cement should be so piled as to prevent the circulation of air, for air carries moisture. In order to prevent circulation of air it is wise to cover the cement with tuild- ing paper or canvas. If the precautions recommended by Mr. Smith are observed, a contractor should run but little risk in storing cement. When payments are made on cement by State Highway Departments, no allowance is made for sacks. Bulk cement possesses a big advantage in this respect, because a contractor is not called upon to tie up his money at the rate of $1.00 per barrel for the non-pro- ductive item of sacks. Experience during the past two years has shown the fallacy of awarding more work than can be completed in one season, for the effect of this practice is to create a serious material shortage and to delay the progress of all contractors. Another result of this practice is to cause an increase in contract prices. Con- tractors who secure the work late in the season can thus afford to pay more for material and labor than those who were awarded work earlier in the year, to the detriment of the latter. Based upon their experience during the past two years the Pennsylvania State Highway Department, one of the best organized in the country, has concluded that about 500 miles of trunk line concrete road is about all they can expect at the present time per working season. It is quite probable of course that as contractors realize more fully the need of proper preparation for the construction season by storing material during the winter months, that this limit of 500 miles per year will be considerably increased, until the Pennsylvania Department is convinced that conditions have changed sufficiently, they intend to limit their yearly awards to 500 miles of road. The standard type of trunk line road in Pennsylvania is reinforced concrete of a 1-2-3 mixture, 18 feet wide, and of an average thickness of 7-l/3 inches. A minimum time limit of l-l/4 minutes for mixing is specified. In the introduction to this thesis an estimate was given of the probable length of time required to complete our primary highway system of 450,000 miles. This estimate was based upon funds available of $1,000,000,000, and an average cost of $40,000 per mile. It is interesting to note that if all states were build- ing roads at the rate which Pennsylvania considers proper, that this would result 19 in an output of 24,000 miles of trunk line highway. This is the same figure arrived at in the previous estimate. Even allowing for increased production due to improved equipment, improved material supply, and better management on the part of contractors, it would seem that an output of 24,000 miles of trunk line highway per year will not be attained for some time. It seems reasonable to suppose, therefore, that at least 20 years are necessary for the construction of our trunk line system of 450,000 miles. In addition to encouraging contractors to store materials during the winter months by paying for material as delivered. State Highway Departments can greatly assist in increasing the production of roads by awarding contracts early and in large sections* The use of li^it railway haulage should also result in an increased yearly output, because work oan be started earlier in the spring than if hauling must be performed over earth roads and the delay from rain should be reduced to a minimum. the final analysis the output of roads will depend upon the managing ability of the contractor, though it is fully realized that some factors, such as poor railroad service, are largely beyond his control. Even here, however, the good manager will take precautions which will minimize as much as possible delay from this source. The contractor who is a good manager and a good organizer will generally secure good results no matter what method or what type of equipment he will employ, though it is reasonable to suppose he will secure better results with some methods and equipment than with others. The contractor who is a poor mana ger on the other hand will not secure good results, as a rule, no matter how elaborate or costly his equipment may be. In road building, as in all operations, the human element enters largely into the final results. 4 % 20 CHAPTER IV. THE APPLICATION OF LIGHT RAILWAY TO HIGHWAY CONSTRUCTION. The idea of using light railway haulage in highway construction is not a new one by any means , and attempts have been made from time to time in the past to use this method of haulage. Until two years ago, however, most of the attempts to use light railways have been rather unsuccessful from the standpoint of both cost and operation. This was due principally to the use of very poor track, and rolling stock Intended primarily for railroad construction. This equipment was too heavy and inflexible for the class of work it was called upon to perform in road building. The motive power consisted of four wheeled steam locomotives weighing from 12 to 20 tons. These heavy machines soon warped the light track so badly that frequent derailments and many delays were caused. A very light type of track was used with short, narrow, open-end corrugated ties, and rail weighing only 12 to 16 pounds per yard. These ties did not have suffi- cient bearing area to support the heavy concentrated loads imposed by the loco- motives, nor did the rail possess sufficient beam strength to carry the load be- tween ties without warping. The rails were fastened to the ties by means of clips, resulting in a track of but little rigidity. The photograph below illus- trates some of this badly warped track. EFFECT OF HEAVY ROLLING STOCK ON LIGHT TRACK Another reason for lack of success in the past with light railway haul- age, lay in the use of V-body dump cars and paving mixers with side loading skips. Unless the track was at the proper elevation and location with respect to the loading skip it was very difficult to dump material into the skip, and in any event it was generally necessary to detail several men to scrape the cars clean. The space required by these side loading paving mixers was so great that it was generally necessary to straddle one of the side forms, while the foira on the side next to the track could only be placed one section at a time as the mixer moved. ♦ 21 V-BODY CARS CHARGING SIDE -LOADING PAVING MIXER Some years ago when light railway haulage was first thought of in connection with highway construction, material was frequently dumped on the sub- grade in long windrows in the same manner as when teams or trucks were used. The possible saving of labor in charging the mixer directly from the railway cars so as to eliminate the wheeling and shoveling crew, was not taken advantage of. The railway method, therefore, did not possess any advantages over any other method, as far as labor at the mixer was concerned. The sole advantage of the railway method at that time was elimination of rutted subgrade, and the somewhat more or less increased reliability of operation due to the fact that haulage could be performed in spite of wet roads. Delays from derailment were so frequent, however, with the makeshift equipment used that increased reliability over other methods was at least questionable, while the investment required was considerably greater. DERAILMENT RESULTING FROM POOR TRACK AND EQUIPMENT 22 1 The old ccnception of highway construction failed to recognize the fact that hauling is hut one of many operations performed by the contractor, though next to providing an adequate supply of raw material it is the most important one. But even so the cost of hauling, alone, is not the proper criterion hy which to judge the merits of a plan of operation. If the only function the contractor had to perform was to haul material from one point to another, then the cost of haul- ing per ton mile would he the proper criterion to use in judging the merits of a plan. Any method of operation which entails unnecessary labor at the mixer, on the subgrade, etc. is not good, even though the cost of performing one of the functions, such as hauling, is low. In other words a road building plant must he considered as a whole, and it must he judged hy its performance as a unit and not simply hy the performance of one of its parts. Failure to recognize this fact was one of the contributing causes to the lack: of success which characterized early attempts to apply light railway haulage to highway construction. The hack-hone of any railway system, especially a light railway system, is the traok. It is possible to operate poor equipment over good track with success, as far as the track is concerned, hut it is not possible to operate even the best of equipment over poor track with any degree of success. Not only should the track he adequate to carry the loads imposed upon it without permanent distortion, hut it should he properly laid and maintained at all times. Without proper attention to laying and maintenance, even the best track will not prove satisfactory. Aside from the fact that the track used was of improper design and inadequate capacity to carry the loads imposed upon it, failure to properly lay and maintain it was one of the big causes for the lack of success which attended early attempts to apply light railway haulage to highway construction. OLD STYLE TRACK OF INADEQUATE CAPACITY Track sufficiently heavy to carry the heavy rolling stock employed in the past was sometimes used, and gave good results as far as successful operation of the trains was concerned. The cost of laying and removing such track however, was excessive ;and portability, so inqportant in an operation of this kind, was sacri- ficed. Wooden ties were generally used in this type of track, hut after the track had been relaid a few times the ties were so M spike-out n as to render them useless. A comparison of fabricated and wood -tie track is inoluded in the appendix. J 23 WOODEN TIE TRACK Prior to 1918, the corrugated type of tie bolted to the rail was almost universally used in light railway track. This tie was rolled by steel mills as a standard section, and was simply sawed off to the length desired for use in the track. As a rule the ties were short, with only a 2 inch or 3 inch projection beyond the rail. This resulted in "center- bound" track, because of the insuffi- cient support afforded by the short projection of the tie. The ties were narrow, about 4 inches to 4^- inches in width, and the open ends permitted the soil to flow when saturated with moisture. Sinking of the track resulted when the ground was at all soft, so it was necessary to place planks beneath the tie6 in order to secure sufficient bearing area. This was one of the big reasons why contractors in the past looked with disfavor upon the use of light railway haulage in highway construction. SOIL FLOW CAUSED BY OPEN END TIES 24 PLANKS UNDER TRACK NECESSITATED BY INADEQUATE TIES Bolting of the ties to the rail resulted in a track of but little rigidity. The rail on one side would frequently creep ahead of the rail on the other, so that it was quite difficult to replace a section or insert a switch# For this reason it was frequently necessary to saw one or more rails. The im- portance of rigidity in track construction has been pointed out by the Joint Committee on Track Stresses of the American Society of Civil Engineers and the American Railway Association, as a result of their researches in this subject. A rigid track distributes a load over a number of ties on each side of the one over which the load is actually placed. In a non-rigid track, however, the tie over whioh the load is actually placed is called upon to carry almost all of the load, inasmuch as it receives but little assistance from adjacent ties. In non- rigid track, therefore, heavy concentrated loads are liable to result in severe deformations. The wide-spread application of light railway to military operations during the World War, resulted in the development of a pressed steel type of tie possessing much greater bearing area than the old type of corrugated tie. This type of tie has since been adopted in light railway track applied to highway construction, principally by The Lakewood Engineering Company, of Cleveland, Ohio. Instead of a projection beyond the rail of only 2 or 3 inches, the pressed steel tie projects some 7 or 8 inches. The ratio of tie projection to the gauge of track in the pressed steel tie type of track, is practically the same as in standard railroad construction. This type of track, therefore, is really standard railroad track in miniature. The old type of open end corrugated tie is usually 4 inches or 4§- inches wide and 32 inches long, whereas the pressed steel tie is 5^ inches wide and 42^ inches long. The pressed steel tie has a flange, approximately 1 inch deep, entirely around the sides and ends of the tie. Not only does this flange grip the ground so as to prevent shifting of the track, but it prevents soil flow and by its confining aotion increases the bearing power of the soil. The importance of this confining aotion is indicated by the investigations of the Joint Committee on Track Stresses, which emphasizes the importance of filling the space between ties with ballast up to the top of the tie so as to prevent flow of the ballast. Not only is the superficial bearing area of the pressed steel tie traok considerably greater than that of the corrugated tie track, but the confin- ing aotion of the flanges is such that the carrying capacity of the pressed steel . . •• . o 5. ■ tie track is practically double that of the narrow, open and corrupted tie track. The rails are riveted to the ties in the pressed steel tie track instead of being bolted, thus providing greater rigidity and consequently lessened danger of local deformations over soft spots in the road bed. The use of a joint tie is another important feature of the pressed steel tie type of track, for it provides a supported joint instead of the suspended type common to the corrugated tie track. This joint tie lessens the danger of surface sends, while at the same time it is equipped with a special device which eliminates the necessity for splice plates and bolts. The pressed steel tie track shown in the photograph below has been in use two years in Illinois soil, and has Deen relaid perhaps a half dozen times or more. In order to insure ease of portability and consequent low cost of laying and removing light railway track, investigation and experience indicates that the wneel loads to which the track is subjected should not exceed l^r tons. This limits the wei^it of four wheeled locomotives to 6 tons, or at the most 8 tons. If it is necessary to use heavier locomotives, they should oe of the eigfrt wheeled type. An eight wheeled locomotive weighing up to 12 tons, or at the most 16 tons, can be used on portable light railway track without harming the track. In order to retain the quality of portability in light railway track the rail should not exceed 20 pounds per yard in weight though sometimes 25 pound rail is used. The standard length of section equipped with 6 pressed steel ties riveted to the rail and 1 joint tie, as manufactured by the Lakewood Engineering Company, is 345 pounds. A mile of such track, containing 352 sections, v/ill weigh 60.72 tons. Experience has shown that a 24-inch g£’.uge of track gives sufficient stability to the rolling stock, which is specially designed with a low center of gravity, and does not require more room than is generally available on the shoulder of a road. In laying light railway track the sections are placed on flat cars, and the laying of the track proceeds from the un- loading point outward, four men are generally required to handle a section of track, and 8 men in charge of a foreman can generally lay about one -half mile of track under normal conditions in 10 hours. At prevailing wages the cost of laying ana removing a mile of lignt railway track has been found to oe about $200.00, exclusive of frei^it and unloading. i t I ; 5 1 PRESSED STEEL-TIE TYPE CF TRACK 26 SIX-TON WHITCOMB GASOLENE LOCOMOTIVE Very few suitable steam locomotives are in the market at the present time as most of them are single truck and are entirely too heavy for light port- able track. The Davenport Locomotive Works, of Davenport, Iowa, manufacture a single-truck, 8-ton steam locomotive which seems to be well suited to light rail- way operation in highway construction. The Lima Locomotive Works, of Lima, Ohio, manufacture a double-truck, 10-ton locomotive of the Shay,- geared type especially for road construction. LAYING LIGHT RAILWAY TRACK The type of locomotive commonly employed in light railway haulage on highway construction at the present time, is a four-wheeled gasolene machine weighing from 3 to 6 tons. Inasmuch as grades of 3 and 4 per cent are frequently encountered even in level country, the 6 ton locomotive is the type recommended for general use. Detailed specifications for a typical machine will be found in the appendix. 27. LIMA 10 TON, DOUBLE TRUCK STEAM LOCOMOTIVE PLYMOUTH 6 TON GASOLENE LOCOMOTIVE When light railways were first extensively used in highway construction, in 1919, a V shaped type of body containing separate compartments for sand, stone and cement was carried on a running gear. Since that time the hatch box system has been developed, enabling 2 boxes to be carried per car. Two general types of batch boxes are on the market, namely the tip-over and the drop bottom type, either of which can be supplied with or without separate compartments for sand, stone and cement. The best practice favors the use of cement compartments, and some stateB will not permit cement to be dumped into the same compartment with sand and stone. The advantage of the tip-over type of box lies in the absence of movable parts or fastenings, while the disadvantage is the difficulty in tipping because of the lowering of the center of gravity & Ls a smaller batch is used than that for which the box was designed. This latter objection has been overcome, however, by the use of adjustable trunnion plates, which enable the point of attachment of the lifting bail to be lowered as the center of gravity of the box is lowered. The best type of tip-over batch boxes are of steel construction with 28 adjustable trunnion plates and a separate cement compartment which can be entirely removed or moved toward one end or the other in accordance with varying ratios of sand and stone. The cement compartment should be provided with a lid, and should be raised from the bottom of the batch box so that rain penetrating the sand and stone will not moisten the cement. Complete drawings and specifications for one of the most widely used types of tip-over batch boxes will be found in the appendix. BATCH -BOX SYSTEM OF LIGHT RAILWAY HAULAGE Batch box cars are generally arranged to carry two boxes per car, as shown in the preceding photograph, when the size of batch does not exceed 5 bags. For a size of batch suitable for a 28-E paving mixer, only one box is carried per car. At the present time the Easton Car & Construction Company, of Easton, Penna. are manufacturing a car for carrying three batch boxes of the 4 bag type. Considerable difficulty is experienced, however, in swinging the middle batch box in and out of place. Considerable thought has been given to the manufacture of a double truck platform car for carrying 4 or more batches. To date, however, such a car has been found to cost more per batch than a single truck car, while the difficulty of handling the middle batch boxes is such as to discourage its use. A double truck car is easier on the track than the single truck type, and undoubtedly the double truck car, equipped perhaps with automatic couplers, will come into general use later on. A common type of double truck car used for general utility hauling is illustrated in the photograph on the following page. When light railway haulage was first applied to highway construction the train speed was very low, due to the poor character of track used, and did not exceed 3 or 4 miles per hour. Under such conditions cars equipped with mild steel axles designed with an ordinary factor of safety, were found to be satisfactory and very little axle trouble occurred. With the introduction of the pressed steel tie type of track properly laid and maintained and with proper limits placed upon the weight of locomotives, operating speeds increased to as high as 20 and 25 miles per hour in some cases with an average of 8 to 10 miles. Under these con- ditions considerable trouble was encountered thru the breakage of mild steel axles, which, investigations by metallurgists, showed,was due to so-called fatigue of metal induced by rapid reversal of stress. It was found necessary, therefore. 29. to increase the factor of safety considerably, and to employ heat-treated, high - carbon steel axles. This is the type of construction used in the best cars at the present time. When light railway haulage was first applied to highway construction, cars equipped with brass or bronze bearings were considered plenty good enough. The heavy locomotives used at that time possessed a hauling capacity more than sufficient to compensate for the increased rolling resistance resulting from the use of bearings of this type. With the advent of the modern improved type of track, permitting higher speeds, and recognition of the fact that wheel loads of locomotives should not exceed 1-g- tons, the weight of locomotive was decreased to such an extent that it became necessary to reduce the rolling resistance of cars to a minimam. The caged-roller type of bearing, and in many oases high class bearings such as the Hyatt roller bearing were, therefore, adopted, and all the best cars at the present time are equipped with such bearings. Actual tests in the field by dynamometer have shown that whereas the rolling resistance of cars equipped with brass or bronze bearings varj^from 30 up to 70 pounds per ton, the rolling resistance of cars equipped with caged roller bearings operating on a high carbon, heat-treated axle has not exceeded 10 pounds per ton. Spring draw bars and bumpers and spring pedestals characterize the modern light railway car, as oompared to the old type. The appendix oontains specifications of one of the most widely used types of batch box cars on the market today. DOUBLE 'TRUCK, GENERAL-UTILITY PLATFORM CAR The indifferent success attending light railway haulage in highway construction previous to 1919, was largely due to failure to operate the railway on standard railroad principles. Very little attempt was made to deliver material at any predetermined rate to the concrete mixer, or to operate trains on a schedule. The result was an erratic and undependable supply of material, and the operation of trains in a '’hit-or-miss*', haphazard fashion. To operate trains on a light railway on a definite schedule was generally considered impossible or impractical, and with the frequent derailments caused by the make-shift character of equipment perhaps it was really so. Light railway operation under the severest conditions in military operations, however, has indicated the entire feasibility of running light railway equipment of proper design on definite schedule in 30 accordance with standard railroad principles. The modern conception of light railway operation applied to highway construction is that a light railway is merely a commercial railway in miniature under intensive traffio, and that all problems peculiar to standard railroad practice apply with equal force to the operation of a light railway. The use of field telephones similar to those employed in military service in order to control the movement of trains, has even been contemplated on light railway operations applied to highway construction of large extent. Modern practice demands the use of equipment of the highest type, especially designed for the conditions peculiar to highway construction. Proper recognition of these fundamental factors has resulted in the large success which has attended the use of light railway haulage in highway construction during the past two years. / * 4 31 . CHAPTER V. TYPES OF LIGHT RAILWAY PLANTS. Two types of light railway plant are commonly used in highway construc- tion, the complete railway plant and the combined railway and motor truck: plant. As its name indicates the complete railway plant affords complete transportation facilities for a job, while the combined railway and motor truck plant makes use of light railway in combination with motor trucks. The combined light railway and motor truck plant has been developed to overcome certain limitations to the use of the complete railway plant on some jobs. These limitations are topographic, geographic, size of job, financial ability of the contractor, and necessity for utilizing truck equipment on hand. The topographic limitations are due, not so much to the steepness of any one grade, as to the distribution of grades. If only one steep grade is en- countered it can generally be negotiated by means of the split train method, the booster locomotive method, the hoisting engine method, or the balanced train method, as described in the following chapter. If, however, a large number of quite widely separated steep grades occur, it becomes necessary to use a booster locomotive or one of the other methods at each grade. This would make the cost of a plant exceedingly high. By using only a mile and a half of track, in a manner described later on, the chances are that not more than one steep grade would be included in the railway portion of the haul. The investment in auxiliary grade olimbing equipment would thus be reduced very considerably. Another topo- graphic limitation to the use of a complete railway system on some jobs in hilly country, is due to the fact that the road frequently lies on a ridge, along which the grades are such as to make railway haul feasible. The unloading point, how- ever, might be located in a valley, and the grade on a road leading from the un- loading point might be excessively steep. In such a case the best method of op- eration would be to haul material in motor trucks from the unloading point to the road under construction, where it could be transferred to light railway oars for haul to the mixer. The geographic limitation to the use of complete railway haulage on some jobs arises from the fact that the unloading point is sometimes located with- in the corporate limits of a city or town. It is generally impractical to lay light railway track on the streets leading from the unloading point to the road under construction. In such a case material is hauled in motor trucks from the unloading point to the job, where it is transferred to light railway cars for haul to the mixer. The purchase of a complete light railway road building plant naturally entails a considerable investment. In order to justify this investment and insure an adequate return on it, it is necessary that the job be of a certain minimum size. Of course if the contractor has a number of short jobs located quite close- ly together he has what practically amounts to one big job, and in such a case a complete railway plant can be economically justified on a smaller job than if only one were available. This question will be considered in detail in a later chapter, but suffice it here to say that on those jobs too small to justify a complete railway plant, a combination of light railway and motor trucks can be used. This combination gives the contractor practically all of the benefits of railway haulage, while at the same time it reduces his investment to a minimum. 3 2. Quite frequently a contractor is unable to make the proper financial arrangements for the purchase of a complete railway plant, even though he recog- nizes the economy and desirability of such a plant on a certain job. He might be in a position, however, to purchase about a mile and a half of track and a com- mensurate amount of rolling stock to use in conjunction with motor trucks, and thus secure the advantages of railvsay haulage. Sometimes a contractor possesses a considerable amount of motor truck equipment and desires to make use of it, while at the same time he realizes the economy of railway haulage and desires to take advantage of it. In such a case a combined plant, using about a mile and a half of track, will permit the contrac- tor to use his motor trucks and at the same time secure the advantages of railway haulage. Later on, if desired, he can easily add to his railway equipment, so as to secure a complete railway plant. In certain sections of the country the average road job will be 5 or 6 miles long, or, if longer, the unloading points will be so located as to permit a 10 or 12 mile job to be handled by means of a few miles of track. Occasionally a 10 or 12 mile job will occur on which all the material must be hauled from one end. This would necessitate the use of 10 or 12 miles of track with a proportion- ate amount of rolling stock, in order to operate with a complete railway system. A contractor would probably find the purchase of so much equipment uneconomical for only one job, inasmuch as he would have but very little use for more than about one-third of it on the majority of his work. In such a case a few rented motor trucks used in conjunction with the railway equipment he already possesses, will enable him to secure the benefits of railway haul without a large additional in- vestment in equipment. The combined light railway and motor truck plan of operation has been developed in order to meet the limitations to the use of a complete railway plant on some jobs as set forth in the preceding paragraphs. In the combined light railway and motor truck plan of operation, batch boxes, each containing complete materials for one batch, are carried on motor trucks from the material yard to the road under construction and over the finished pavement as far as specifications permit. BATCH BOXES CARRIED ON MOTOR TRUCKS 33 Practioally all state specifications permit traffic over the finished concrete road after the expiration of 21 days, and over the finished concrete base after the expiration of from 10 to 14 days. At the point where the concrete is not sufficiently cured to carry traffic, the loaded batoh boxes are transferred from the trucks to light railway cars for haul pasiedr the uncured portion of the concrete to the mixer. It is obvious that this plan of operation requires only sufficient railway track to extend past the portion of the concrete not yet suffi- ciently cured to carry traffic. Each day as a section of concrete comes of proper age to carry traffic the transfer point oan be advanced, and the track no longer needed in the rear can be picked up and relaid in advance of the mixer. A small crane or a light portable derrick with an 18 foot boom and about 2 ton capacity, is the best device for transferring batoh boxes from truck to railway cars and vice versa. An "A" frame spanning the road equipped with a chain hoist and a trolley is sometimes used as a transfer device. HAULING MATERIAL OVER CURED CONCRETE, COMBINED SYSTEM TRANSFERRING BATCH BOXES FROM TRUCK TO CARS 34 The combined light railway and motor truck plant possesses practically all the advantages of a oomplete railway plant, such as elimination of wheeling and shoveling crew, reduction of labor in trimming and retrinming subgrade, elimination of lost and dirty material due to dumping on the subgrade, etc* Inas- much as the motor trucks operate over an improved road and the remainder of the haul is over steel rails, delay due to rainy weather should be reduced to a mini- mum. The combined light railway and motor truck plan of operation, in common with the complete railway plan, permits the placing of conorete to begin at the point nearest the material yard. This eliminates delay in placing concrete, and permits the concreting and grading operations to be performed simultaneously, A large monthly estimate is thus insured early in the life of the job, and much needed working capital provided. The railway portion of a oombined light railway and motor truck haulage system, can easily be extended at any time so as to form a complete railway plant. Where a contractor desires to reduce his investment to a minimum it is recommended that motor trucks be rented,as a trucking company can afford to rent their trucks for less than the cost to a contractor of operating his own truoks. This is due to the fact that the trucking company operates all the year round, while the con- tractor operates only a part of the year and must absorb all the plant charges during the short road building season* While not quite so economical as a com- plete railway plant, where conditions permit this type to be used, the oombined light railway and motor truck plant will effect very considerable economy over other methods of doing work where material is dumped on the subgrade or all of the haulage is performed over it. The combined light railway and motor truck plant offers to the contractor of limited means an opportunity to perform his work in an economical manner, and as he secures more capital he can add to his equipment, if desired, so as to eventually secure a complete railway plant. In operating a oom- bined plant, practically all contractors rent the motor truoks. Sometimes material is hauled in dump body trucks and is dumped near a small portable bin, into which it is handled by a crane equipped with a clam shell bucket , a bucket elevator, a portable bucket loader, or a short belt conveyor. Material is occasionally dumped on the finished pavement at the transfer point and shoveled into the batch boxes on the cars by hand, when, for some reason, a con- tractor does not desire to install a portable derrick or bin. This method is not economical and is only a make-shift. To supply a 14-E paving mixer a gang of from 8 to 10 shovelers are needed. The objection to the method of hauling material in bulk is the expensive rehandling equipment necessitated, and the cost of this rehandling. The best method of operating a combined plant is to load the batch boxes with complete materials at the material yard, haul them out to the road on motor trucks, and transfer to railway oars by means of a portable derrick. When batch box haulage is used it is unnecessary to haul cement bags out on the road and thus risk losing them, or bulk cement can be employed. The method of lauling material in bulk precludes the economy in handling cement which the batch box sys- tem insures. Another advantage of the batch box plan is the fact that a platform truck or a plain truck chassis equipped with a light wooden frame to hold the batch boxes, can be used. This reduces the cost of rental or purchase of trucks andin- creases the number available for service. Dump body trucks can also be used to oarry batoh boxes if necessary. Many times it is practical to use trailers with the batch box system, and inasmuoh as these trailers are double ended the problem of turning them is solved. The oomplete railway plant, as previously mentioned, affords oomplete transportation facilities for a job. Detailed plans of operation for this type of plant, will be considered in a later chapter. 25 A problem quite frequently encountered in operating a light railway plant, is that of crossing the tracks of a standard gauge railway. Wherever it is possible to avoid crossing standard gauge tracks they should be avoided, but if necessary the crossing can be readily effected. Some railroads require a contrac- tor to post watchmen about a half mile on each side of the crossing point* equipped with telephones, in order to notify the crossing watchman of the approach of trains. Other railroads do not require these precautions, and are content if a watchman is placed at the crossing itself. Needless to say the contractor should take every precaution to insure against an accident at the crossing point. A number of different methods have been devised for carrying light railway track over standard gauge track. All these methods are alike in that no outting of the rails in the standard gauge track is contemplated, nor would it be permitted by the railroad oompany. The type of crossing consists of a section of light railway track placed over the standard gauge track, in such a fashion that the light railway track can be removed after each passage of the train. The photographs below illustrate a number of light railway crossings. LIGHT RAILWAY GROSSING HINGED HORIZONTALLY 36 COUNTERBALANCED LIGHT RAILWAY CROSSING HINGED VERTICALLY The first of the foregoing illustrations shows a 15 foot section of light railway traok hinged at one oorner so as to permit it to he swung horizon- tally away from the standard gauge track after the passage of each train. The I second illustration shows two Yg- foot sections of track hinged so as to he swung hack vertically away from the standard gauge track. The third illustration shows two 7-§- foot sections hinged vertically, and so equipped as to he swung hack vertL oally hy means of counterweights. These counterweights are attached to lines passing over sheaves on the "A” frame. The particular crossing illustrated in this photograph was at a point where the standard gauge railroad was located on a steep grade, and on a curve in a cut of considerable depth. 37. CHAPTER VI. GRADES, SPEED AND SIZE OF TRAINS The hauling capacity of a locomotive is a function of the weight on the driving wheels, and the character of metal in the wheel. With equal weight on the drivers and the same type of metal in the wheels, the hauling capacity of one type of locomotive is the same as that of another if sufficient engine power is provi- ded to slip the driving wheels on dry rail. In full sized commercial locomotives some allowance must he made for the effeot of the reciprocating parts on rod driven locomotives as compared to gear driven or electric driven machines, hut for the small locomotives used on light railway the foregoing statement is true. Tractive effort is the force exerted hy the locomotive at the drivers, and is a function of the adhesion between the driving wheels and the rails. All of this force, however, is not available for pulling a train, as a certain amount of it is consumed in overcoming the rolling resistance of the locomotive itself. The force at the draw bar of the locomotive available for pulling a train, is equal to the tractive effort minus the rolling resistance of the locomotive itself. The engine power provided is, of course, partly consumed in overcoming friction within the mechanism of the locomotive, and in other losses. The factor of adhesion between steel rails and steel driving wheels is generally taken at 25 per cent when the rail is dry, while the factor of adhesion between cast iron wheels with a chilled tread and a dry rail is generally taken at 20 per cent. When the rail is wet both of these factors are reduced consider- ably, but, on the other hand, the application of sand will serve to increase them up to a limit of approximately 40 and 35 per cent for steel and oast iron wheels respectively. The rolling resistance of a train is the force required to maintain a constant speed by overcoming the retarding influence of friction in the bearings, friction between wheels and rails, and all other forces tending to retard the move- ment of the train. The force required to accelerate a train must not only over- come the rolling resistance, but it must also overcome the inertia. The force employed in overcoming the inertia of a train is stored in the train in the form of kinetio energy, which later on tends to keep the train in motion when the speed is reduced. It is apparent, therefore, that greater force is required to acceler- ate a train than to keep it going after a start has once been made. The retarding influences of friction would in time consume the kinetic energy stored in a train, providing, it was operating on the level so that the force of gravity would not come into play, but brakes are provided in order to consume this kinetic energy thru the medium of friction to enable the train to be stopped wherever desired. In standard railroad praotioe where trains operate at a high rate of speed, the effect of atmospheric resistance must be taken into account. This factor can be neglected, however, in the small trains operated at the comparatively low rate of speed prevailing on light railway employed in highway construction. The frictional resistance of bearings forms the greater part of the rolling resistance of a train, and this frictional resistance depends largely upon the type of bearing used. In standard railroad practioe the rolling resistance of cars in good condition is generally about 5 or 6 pounds per ton, but the rolling resistance of light railway cars varies from 10 to 70 pounds per ton. The lower value is obtained when caged roller bearings and high carbon, heat-treated axles 38 are used, while values from 20 pounds up to 70 pounds prevail with "brass or "bronze hearings and mild steel axles. The importance of reducing rolling resistance to a minimum is apparent when we consider that a locomotive can pull practically three times as heavy a train on the level with a rolling resistance of 10 pounds per ton as it can pull with rolling resistance at 30 pounds per ton. The limited draw "bar pull available in the small type of locomotive featured in modern light railway practice in order that wheel loads will not exceed lg- tons, makes reduc- tion of rolling resistance of cars to a minimum doubly important. The effect of grades is to increase the rolling resistance of a train 20 pounds per ton for each per cent of grade, and to decrease the draw bar pull of the locomotive 20 pounds per ton weight of the locomotive. This is due to the effect of gravity, and a proof of this phenomena can easily be effected by means of a diagram of forces. The application of this law can perhaps best be demon- stated by means of an example. A 6 ton locomotive having a weight of 12,000 pounds on its drivers and cast iron driving wheels with chilled treads, will have a draw bar pull of 2,400 pounds on the level. Such a locomotive is capable of pulling a train weighing 120 tons on the level, with a rolling resistance of 20 pounds per ton. Inasmuch as the draw bar pull of the locomot ive is decreased 20 pounds for each ton of weight for each per cent of grade, the draw bar pull on a 1 per cent grade would be 2,280 pounds* The rolling resistance of a train, on the other hand, is increased 20 pounds per ton for each per cent of grade, making the rolling resistance 40 pounds per ton on a 1 per cent grade. The locomotive we have in mind, therefore, could pull a train weighing 57 tons on a 1 per cent grade. It is thus apparent that a 1 per cent grade will reduce the hauling capacity of a locomotive to less than half of its capacity on the level, when the rolling resistance of the train on the level is 20 pounds per ton. If the rolling resistance on the level is only 10 pounds per ton, the hauling capacity of a locomotive would be reduoed by one- half on a grade of only one-half of one per cent. The serious effect of grades on the size of a train is thus clearly apparent, and shows why standard railroad practice generally sets a maximum of about three-tenths of one per cent to its main line grade. The lower the rolling resistance of the cars, the greater is the influence exerted by grades on the size of train. The hauling capacity of any locomotive can easily be computed in the manner shown above, but sometimes a formula showing the relations between the speed and hauling capacity is convenient. For sake of illustration a formula of this kind, applicable to a typical 6 ton gasolene locomotive widely employed in light railway haulage in highway const ruction, will be derived. This locomo- tive is equipped with a 50 horse power engine and can exert a draw bar pull on the level of 2,400 pounds at 5 miles per hour and 1200 pounds at 10 miles per hour. The adhesion of the driving wheels to the rail is 20percent under normal condi- tion. The rolling resistance of the train will be assumed to be 20 pounds per ton. Let Let Let Let Let Let Let Let Let Let E W S L G V H* H E D repre sent t» train resistance on the level weight of train in tons speed in miles per hour distance traveled in feet per minute per cent of grade vertical distance lifted in feet per minute engine horse power draw bar horse power ratio of draw bar horse power to engine horse power draw bar pull in pounds 39 L = 526 ° . s . = 88 S 60 D L - e H » - D 86 S - D S 33000 ” ~ 33000 375 H = E H’ When S = 10, D = 1200, therefore E = 0.64 and H - 0.64 H* H* z 50, therefore H I 32 R I 20 W V : G L : 88 G S H - R L f 2000 (¥ + 6) V = 20 W 88 S 4 2000 (W 4 6) 88 S 5 z 33000 33000 S £~W » 100 G (W 4 6l? - s = 18.76 600 32 + 100 G (W + 6) nr _ 600 (1 - G S] n _ 600 - W 3 * w “ S (1 * 100 &)* 5 “ 100 S (w + 6) Experience has shown that the performance of locomotives in the field is entirely in accordance with the expressions for S, W, and G shown above. In applying this formula, however, in which the hauling capacity of the looomotive varies inversely with the speed, it must not be forgotten that the limiting faotor at all times is the adhesion between the driving wheels and the rails. For instance. if we assume a grade of 4 |)er cent and a speed of 2 miles per hour, we get a value for W of 55.2 tons. Inasmuch as the rolling resistance of the train is increased 20 pounds per ton for each per cent of grade, the draw bar pull nec- essary to haul a train of this weight up a 4 per cent grade is 5,520 pounds. We have previously seen, however, that the maximum draw bar pull which a 6 ton locomo- tive equipped with cast iron drivers can exert is 20 per cent of its weight, or 2,400 pounds. It is apparent, therefore, that a locomotive of this type cannot haul a 55 ton train up a 4 per cent grade. The discrepancy arises from the fact that the formula does not apply for speeds lower than 5 miles per hour, because at lower speeds the pull which the engine of the locomotive can develop exceeds the adhesion of the locomotive to the rail. In other words the draw bar pull will not be increased tjy operation at a speed lower than 5 miles per hour, as the formula indicates, on account of the limiting factor of the adhesion of the driving wheels to the rail. It is entirely possible to operate the locomotive at speeds much lower than 5 miles per hour, but the draw bar pull will not vary inversely with the speed, as indicated by the formula, when the rate is less than 5 miles per hour. Of course if the rails are sanded or steel driving wheels are used on the locomo- tive, the adhesion will be increased to such an extent that the draw bar pull will vary inversely with the speed, as shown by the formula, at rates lower than 5 miles per hour. It is not wise, however, to assume conditions other than those of normal dry rail. The limiting factor to the hauling power of any looomotive is the adhesion between the driving wheels and the rail, and engine power in excess of that required to spin the driving wheels under normal conditions will not increase the hauling power. 40 A 3 ton gasolene locomotive, equipped with cast iron driving wheels, of the type conmonly used in highway construction, can exert a draw bar pull on the level of 1,200 pounds at 5 miles per hour and 600 pounds at 10 miles per hour under normal conditions. The formula for the hauling capacity of this locomotive is W - 300 (1 - G S) “ S (1 + 100 G)* If steel driving wheels are used, in place of cast iron wheels with chilled tread, the factor of adhesion between the drivers and the rails will be increased to 25 per cent. A 6 ton looomotive with steel drivers can exert a draw bar pull on the level of 3,000 pounds at 5 miles per hour, and 1,500 pounds at 10 miles per hour. The formula for hauling capacity for a 6-ton locomotive with steel drivers will be ¥ = 7£P ~ s 4-« W z 87 , 5 ( 1 - fi S) i s the expression of S (1 f 100 G) S (1 + 100 G) hauling capacity of a 3 ton looomotive equipped with steel drivers. The principal advantage of steel driving wheels is not the increased draw bar pull on the level resulting therefrom, but the increased hauling capacity on grades. The effect of gravity is to retard a train ascending a grade, and to reduce the hauling power of the locomotive. On descending grades, however, gravity tends to increase the speed of the train, and to decrease the draw bar pull re- quired to overcome the rolling resistance of the train. When the grade is suffi- ciently steep the draw bar pull required to overcome the rolling resistance of the train beoomes negative, so that brakes must be provided to retard the train. The effect of gravity on a descending grade is to exert a pull of 20 pounds per ton weight of train and locomotive for each per cent of grade. On a 1 per cent des- cending grade, therefore, the effect of gravity is just sufficient to overcome the rolling resistance of a train of 20 pounds per ton. On descending grades a high rolling resistance is an advantage, for it assists in retarding the train and thus makes oontrol by means of brakes easier. In standard railroad practice, grades known as velocity grades are fre- quently used. These grades consist of opposing descending and ascending grades. On the descending grade the train is permitted to run without the application of brakes, and the kinetic energy attained is utilized to ascend the opposing grade. In this manner the force of gravity is called into play so as to reduce fuel con- sumption. In light railway operation as applied to highway construction, however, velocity grades are generally not practical, because of the light equipment and the temporary character of the track. The effect of a descending grade on the speed of a train can be demon- strated in the following manner: Let V represent the velocity in feet per second Let KE n the kinetio energy of a train at V feet per second Let S it speed in miles per hour Let g it the acceleration of gravity Let H •» height in feet to which KE will lift train Let W n weight of locomotive and train in pounds Let G tt per cent of grade Let L M horizontal distance in feet Let E It rolling resistance at 20 pounds per ton : ^ 41 H , V = 1.467 S, H = 0.03344 S 2 , S = 5.47^H“ 2 g H - G L, V 2 : 2 g H : 2 g 5 L KE z l/2 M V 2 ; l/2 — 2 gG L If SL : the kinetic energy of the train 2 A ® providing- the rolling resistance were zero. The retarding action due to rolling V/ L resistance, however, is "^oo* ¥5 1- ” l/2 MV 2 : w ^ = actual KE of train. 100 2 g 51- 100 “ 2 g * «2 _ 100 G L - L 1,55 ’ 100 G L - L Z 1.55 V' - t/L .UQQ-Gl^-11 1.55 V 6 z 2.15 S' s 2 L (100 G - 1) g _ ,/ L (100 G - 1), 1 3.31 ’ 3.31 S represents speed due to the effect of gravity, assuming the train starts from the top at a stand still. If the train approaches the top of the grade at a certain speed, this speed should he added to that due to gravity in order to obtain the final speed at the bottom of the grade. A train with a rolling resistance of 20 pounds per ton, will attain a speed due to gravity of 25 miles per hour at the bottom of 500 feet of 5 per cent grade. If the train resistance is less than 20 pounds per ton, the speed attained would be even greater than 25 miles per hour. While speeds of 20 and 25 miles per hour are occasionally attained on light railway used in highway construction, it is not considered wise to operate at a rate of speed exceeding 10 or 15 miles per hour. The braking power of a locomotive depends upon the adhesion of the driv- ing wheels to the rail, in the same manner that the hauling power depends upon this factor. Theoretically, therefore, a locomotive can control the same weight of train on a descending grade, by means of its brakes, that it can haul up an ascending grade. An overloaded locomotive on an ascending grade will stop of its own accord, however, while an overloaded locomotive on a descending grade, if the cars are net equipped with brakes, cannot be stopped. Descending grades are a greater source of danger and must be more carefully watched, than ascending grades. Fortunately it is unnecessary to depend upon the brakes on the locomotive alone, for brakes can also be placed on the cars. On a light railway train, however, automatic brakes are too expensive, and it is not practical to apply brakes on more than three cars, one next to the locomotive and two at the end of the train, unless additional men are provided for this purpose. As a rule but one train man is provided, and he ride3 between the two last cars in order to apply the brakes on them. The brakes on the car next to the locomotive can be applied by the locomo- tive operator. The braking power of cars is oomputed in the same manner as that of the locomotive, by multiplying the weight of the car by the factor of adhesion be- tween the wheels and the rails. * 42 As mentioned in the foregoing paragraph speeds of 20 and 25 miles per hour are sometimes attained in light railway operation, hut the average operating speed is from 8 to 10 miles per hour. Experience indicates, however, that an aver- age speed of 6 miles per hour is the proper speed to use in proportioning the amount of rolling stock required. In rolling country where the ascending and descending grades balance one another fairly well in length and degree., the speed of operation is almost as great as it is in level country. This is due to the fact that descending grades compensate, to a certain extent, for the ascending grades. Due to the necessity of applying brakes in order to keep the speed within safe limite, the descending grades do not entirely compensate for the ascending grades. In most cases, however, an average speed of 6 miles per hour can be used as a basis for proportioning the amount of rolling stock required in hilly country as well as in level country. If desired, the average speed of operation in hilly country can be com- puted from a profile by means of the formula derived on page 39. This formula en- ables the speed of train to be computed on grades, while on level sections the speed can be assumed at 10 miles per hour. On down grades, also, a speed of 10 miles per hour can be used. On an ascending grade the speed derived from the formula will be the speed at the top of the grade, and the mean speed for the entire grade can be obtained by averaging the speed at the top and the speed at which the train approached the bottom. The mean speed of a down grade can be obtained by averaging the speed at which the train approached the top, and the assumed speed of 10 miles per hour at the bottom. While this is not strictly correct, it is accurate enough for all practical purposes. The average operating speed for the entire job can then be obtained by multiplying the length of each grade and level stretch by its average speed,and dividing the sum of these products by the total length of the road. Exoept where ascending or descending grades predominate, it is seldom nec- essary to go to the refinement of computii^g the weighted mean speed from the pro- file. Specifications generally require concrete to be mixed a certain minimum time, generally one minute. Under such conditions a 14-E paving mixer should aver- age about 30 batches per hour, and a 21 -E paving mixer about the same. A 28-E paving mixer should produce about 24 batches per hour. The object of light railway haulage, therefore, is not to deliver the maximum amount of material possible be- tween two points, but rather to so coordinate haulage operations as to supply the mixer at a predetermined rate of about 30 batches per hour. The size of train should be such as to supply the mixer at the predetermined rate during the interval between arrival of trains, providing topographic conditions are such as to permit this to be done. In level country it is possible to haul trains of 30 to 40 loaded cars, but unless the length of haul is such that the intervals between the arrival of trains at the mixer are sufficiently great to enable the mixer to con- sume the amount of material carried by such a train,a train of this size would not be economical. In other words the size of trains on any particular job is not always determined by topographic conditions, and consequently the hauling capacity of the looomotive, but often by the length of time required per round trip between mixer and material yard. The time element as well as the topographic element must be considered in determining the size of trains. Suppose, for instance, that operations were being carried on in level country on a 2 mile haul, and that a 6 ton locomotive could haul a 40 car train. At a speed of 6 miles per hour, the locomotive would make a round trip in 40 minutes. Allowing 5 minutes for switching trains at the mixer and the same amount of time at the material yard, a total of 50 minutes would be required per round trip. Three ! trains would be necessary, 1 at the mixer, 1 at the material yard, and 1 in transit 4 4 v 43 A 40 oar train would carry 80 batches, or a sufficient amount of material to supply the mixer for 160 minutes at the rate of 30 batches per hour. On the round trip of 4 miles the locomotive can arrive at the mixer at 50 minute intervals, and during this interval the mixer would consume only about 25 batches. A train of 12 or 13 cars, therefore, would be sufficiently large to supply the mixer at the predetermined rate. If 40 oar trains were used a total of 120 cars and 240 batch boxes would be needed, while 3 trains of 13 cars each would make a total of only 39 cars and 78 batch boxes. It is obvious, therefore, that in this case it would not be economical to load the locomotive up to its maximum hauling capacity. The point it is desired to emphasize is that in level oountry the size of train is frequently determined by the length of running time between the mixer and the material yard, because the rate of operation of the mixer is limited by specifica- tions. The problem of operating a light railway in highway construction is not merely one of transporting a maximum amount of material between two points, but rather one of so coordinating the transportation efforts as to supply the mixer with the maximum amount of material which specifications permit it to consume. TWENTY-FIVE CAR TRAIN IN ARIZONA THREE CAR TRAIN ON 8.2 PER CENT GRADE IN PENNSYLVANIA 44 1 The preceding photographs illustrate very clearly the effect of grades on the size of trains. The locomotives employed in "both of these operations are 6 ton gasolene, friction drive machines, of equal hauling oapacity. In level country the length of running time "between the mixer and the material yard frequently determines the size of train, but in hilly country, of oourse, the size of train is limited by the grades. It is necessary, therefore, to run trains at more frequent intervals in hilly country than in level country. The influence which grades exert upon light railway haulage, however, is not so much due to the actual steepness of the grade, as it is to their number and dis- tribution. If only one steep grade exists on a job it oan be surmounted by means of a booster locomotive, or one of the other methods described in the following paragraphs. If the steep grades are many in number, or so distributed that a booster locomotive or some other method is required at each grade, the question of grades becomes serious because of the increased amount of equipment required. Several methods of negotiating steep grades are in general use at the present time. The principal methods are known as the booster method, the split train method, the hoisting engine method, and the balanced train method. The booster method consists of using an extra locomotive to push or pull a train up a steep grade. By this method a train of approximately twice the weight that a single locomotive can handle, can be taken up a grade. Instead of using an extra locomotive, other motive power such as a motor truck, a tractor, or even a team of horses is sometimes used to pull a train up a grade. Auxiliary motive power of this kind is generally used where but one steep grade must be considered. BOOSTER LOCOMOTIVE METHOD OF NEGOTIATING STEEP GRADES Perhaps the most popular method of surmounting steep grades, is by what is known as the split train method. In this method the looomotive is placed in the middle, and half of the train taken up the grade at a time. The split train me- thod is especially adapted to a job containing but one steep grade, and in such a case it is generally more economical than the booster locomotive method. A certain amount of time is lost, of course, by the split train method, and where a number of grades exist the running time is sometimes so increased that it is questionable 45 whether to purchase the additional cars and locomotive needed to properly supply the mixer or to purchase booster locomotives. Conditions surrounding each job must govern in such a case. MOTOR TRUCKS HAULING- TRAIN UP STEEP GRADE The time required to negotiate a grade by the split train method can be estimated in the following manner: Assume a 6 per cent grade 1,000 feet long. Under normal conditions, a 6 ton locomotive equipped with steel driving wheels will pull a 5 car train carrying 10 batches up such a grade. Assume that the other grades are such that an 8 car train can be used. By placing the locomotive in the center of the train, 4 cars can be taken up the 6 per cent grade at a time. The weight of a 4 oar train, each car carrying 2-4 bag batches of material, is about 13-l/2 tons, and a 6 ton looomotive will haul such a train up a 6 per cent grade at a speed of 5*5 miles per hour or 484 feet per minute. Assuming the train stops 100 feet from the bottom of the grade and runs the same distance beyond the top, the locomotive should cover the distance of 1,200 feet in about 2.5 minutes. Coming down the grade the locomotive will average about 10 miles per hour, so that 1.5 minutes are needed for this purpose. Allowing l/2 minute at the bottom of the grade to set brakes on oars and to uncouple and the same amount of time at the top of the grade, a total of 2 minutes will be required for this purpose. Adding the time required to run up and down the grade, gives a total of 8.5 minutes which are required to negotiate this grade by the split train method. At a speed of 6 miles per hour, a train will travel 1 mile in 10 minutes. The extra time consumed on this grade due to splitting the train is 6 minutes, so that the effect of this grade is the same as if the haul were increased 0.6 of a mile. If a number of grades are encountered, it is obvious that the running time of trains might be so increased as to necessitate additional equipment in order to properly supply the mixer. The hoisting method of steep grade operation, consists of placing a hoisting engine at the top of the grade and attaching a line to the train. The pull which can be obtained from the hoisting engine depends upon the si£e of the engine, and upon the size and speed of the drum. When a hoisting engine is used to assist a train up a steep grade, it should be set at one side of the road and the cable passed around a sheave in the center of the track. Empty trains on the i 46 way down grade, pull the cable to the bottom in order that it may be in readiness for the next ascending train. The hoisting engine method is limited by the line capacity of the drum, and by curves in the traofc. The balanced train method utilises the weight of the empty descending train to assist the loaded train up the grade, by means of a cable passed around sheaves at the top. Double traofc is generally used in this method, but a single traofc with a passing siding half way up can be used if the sheaves at the top are both placed outside of the rails. In operation the cable is attached to the rear car of the empty train at the top of the grade, and to the loaded train at the bottom of the grade. The operator on the empty train allows his train to descend without the application of brakes, so as to give the force of gravity full play. In this method of operat ion, the loaded and empty trains alternately occupy right anA left hand tracks or passing siding. Assume a 6 ton locomotive with steel wheels is to negotiate a 6 per cent grade, with an 8 car train. Such a train, each car carrying 2-4 bag batohes of material, would weigh about 27.2 tons. On a 6 per cent grade the locomotive could exert a draw bar pull of 2,280 pounds* while a train of this weight, with a rolling resistance of 20 pounds per ton on the level, would require a pull of 3,808 pounds. An additional pull of 1,528 pounds over the draw bar pull must be provided, if the train is to be hauled up the grade in question. An empty car carrying 2 steel batch boxes will weigh 2,000 pounds, so that the empty train with the locomotive will weigh 14 tons. The influence of gravity will cause a pull of 20 pounds per ton for each per cent of grade, or 120 pounds per ton on a 6 per cent grade. Subtracting the rolling re- sistance of 20 pounds per ton, leaves a net pull of 100 pounds due to gravity. The pull delivered by the 14 ton descending train, therefore, would equal 1,400 pounds. Inasmuch as an additional pull of 1,528 pounds is required, the weight of the descending train is hardly sufficient. By the use of sand, however, this grade could be surmounted very nicely. If the rolling resistance were only 10 pounds per ton the descending train would furnish a 1,540 pound pull, while the additional pull needed by the ascending train would be only 1,256 pounds. Sometimes it is possible to so arrange passing sidings and schedules, that trains will meet either at the top or the bottom of the grade. In such a case the looomotive on the empty train can be detaohed, and utilized as a booster. The delay would not be quite as great as that required by the split train method, but the location of the passing siding at the top or bottom of the trade might oause a serious derangement of the operating sohedule. At times, however, this method can be employed, and it is well to keep it in mind. Considerable thought and study has been given to the problem of develop- ing a raofc and pinion method for use on steep grades. The idea is to bolt the rack to the track in sections, and to place a pinion on an axle of the locomotive so that it would mesh with the rack in somewhat the same manner as in the cog wheel system. The difficulty of securing proper meshing between the rack and pinion is such, that to date this method has not proven practical. Whenever possible it is preferable to pull a train by means of the locomotive, rat her than to push it. Pushing a train causes the car wheels to jam against the rail, and not only increases the rolling resistance but increases the possibility of derailment. The increased rolling resistance caused by pushing light railway trains, is such as to reduce the capacity of the locomotive very con- siderably. The 6 ton gasolene locomotive is the type best adapted to light railway 47 operation in highway construction at the present time, inasmuch as the wheel loads to not exceed l-l/2 tons and the draw "bar pull is sufficient to enable a fair size train to he used. In level country the 3 or 4 ton looomotive is frequently used, hut even here opinion is gaining ground that the 6 ton machine is the best type. A 10 ton geared looomotive on double truoks suitable for highway construction, illustrated on page 27, is manufactured by the Lima Locomotive Works, of Lima, Ohio The difficulty of designing a small machine of this type, so the manufacturers claim, is suoh that the available draw bar pull is not commensurate with the weight of the machine. The draw bar pull on this locomotive is only 3,400 pounds, in- stead of the 5,000 pounds which a machine of this weight, equipped with steel wheels, should deliver. This particular locomotive does not possess sufficient engine power to develop the draw bar pull which its weight would enable it to deliver, and obviously it is not as efficient a unit as a 6 ton locomotive which utilizes all of its weight in pulling a train. The additional weight in an under- powered looomotive is of advantage only for braking purposes. There is urgent need at the present time for a 10 or 12 ton double truck gasolene locomotive, designed with a low center of gravity and a short wheel base. No such machine is on the market, in fact there are really no satisfactory locomotives exceeding 6 tons in weight available for light railway operation in highway construction today. Experience indicates that gasolene is the best fuel for light railway operation in highway construction. Three ton machines, as a rule, are not used on grades exceeding 4 per cent, while 6 ton locomotives are in successful operation in the State of Pennsylvania on grades up to 8 per cent. The photograph on page 43 shows a 6 ton locomotive hauling a 3 oar train up an 8.2 per cent grade, each car carrying 2-4 bag batches of material for a 1-2-3 concrete. The question of limiting grades is not one of the maximum grade which a locomotive can climb, but one which it can climb while pulling a train of at least 3 cars. Theoretically a locomotive can climb a 20 per cent grade on dry rail, but this is of no practical interest to the con- tractor for he is concerned only in the size of train which a locomotive can handle on a given grade. Very seldom are grades in excess of 10 per cent permitted on any road which is to be improved with a so-called permanent pavement, and if steeper grades do occur they are generally short and can be handled by one of the methods previously described. Experience during the past two years indicates that light railway haulage can be economically employed, on any grades which are likely to be encountered on roads inportant enough to be inproved with a pavement involv- ing the use of concrete. 48 CHAPTER VII. TRAIN SCHEDULES AND LOCATIONS OF SIDINGS. It has previously "been pointed out that one of the reasons for the indifferent success which attended the early efforts to apply light railway haul- age to highway construction, was the lack of proper train schedules and failure to operate trains in a systematic manner. In order properly to operate a light railway system so as to supply material to the mixer at the required rate, it is necessary that the trains he operated on regular schedule. Each train should he given a number, and the operator inqpressed with the fact that he is to leave the material yard at such and such a time, to meet other trains at passing sidings at such and such a time, and to arrive at and leave the mixer at a certain time. A time schedule should he computed, and should he changed from time to time as the length of the haul necessitates. In order to assist in maintaining the schedule and to insure that help is speedily forthcoming in case of trouble, field tele- phones similar to those employed by the United States Army can he used. These phones are not very expensive, and they can he attached, in many cases, to wire fences along the way. On a big job these telephones could he used to control the movement of trains. While such an arrangement might seem elaborate at the present time, refinements of this character will come into more general use as the value of, and necessity for, good organization is more fully realized. Schedules can he computed and used in either tabular or graphical form. The computation of a tabular schedule, from which a graphical schedule can he constructed, is shown below. The length of haul from the material yard to the mixer is assumed to he 4 miles, and the speed of the train 6 miles per hour. An allowance of 5 minutes for lost time on switches is made, though the rate of oper- ation, 6 miles per hour, is generally sufficiently low to provide for this feature. An allowance of 5 minutes for switching trains at the mixer and the same amount of time at the material yard, is made. An 8- car, 16-hatch train, is assumed, with the mixer operating at 30 hatches per hour. Train Arrive Leave Arrive Leave Arrive number at yard Yard at miser Mixer at yard 1 7:10 7:15 8:00 8:05 8:50 2 7:42 7:47 8:32 8:37 9:22 3 8:14 8:19 9:04 9:09 9:54 1 8:46 8:51 9:36 9:41 10:26 The schedule shows that train #1 arrives at the yard at 8:50, practi- cally in time to take the place of what would have been train #4. Consequently on this particular job, 3 locomotives would be sufficient. Inasmuch as one train is left at the mixer while another is at the material yard and still another is attached to each locomotive, it is apparent that 5 trains of 8 cars each are re- quired or a total of 40 oars and 80 hatch boxes. Not only does this schedule in- dicate the time at which trains are to leave and arrive at various points, hut it also indicates the amount of rolling stock required. A short-out method of determining the amount of rolling stock required consists of computing the round-trip time, and consequently the number of round trips per day. For instance, in the foregoing example a 4-mile haul is assumed at _i 49 6 miles per hour, with a 5-minute delay on switches, at the mixer, and at the material yard. The time required per round trip is 100 minutes, enabling a loco- motive to make 6 round trips per 10-hour day. Each car carries 2 hatches, so that 6 train loads of 8 cars each amount to 96 batches. Three locomotives, therefore, could deliver approximately 300 batches to the mixer, and by speeding up a trifle they could easily deliver 300 batches. The determination of the number of trains and cars required, is effected as in the previous method. A time schedule, similar to the one shown on the preceding page, should be tabulated for the entire day. As the length of haul increases and the loca- tion of the sidings are changed, the time schedule should be properly modified. In order to maintain train schedules it is necessary that passing sid- ings be located at the correct places, for if this is not done considerable time will be lost by trains waiting for each other. In the past improper attention has been paid to this feature of light railway operation, or if the sidings were correotly located at first they were not changed as the length of haul and the number of trains changed. The difficulty of changing siding locations with the make-shift type of track employed in the past, was no doubt responsible to a large degree for neglect of this important feature. The track in use at the present time is manufactured especially for light railway operation in highway construc- tion, and is so designed as to permit of easy and rapid changing of passing sid- ings. As the length of haul from the material yard to the mixer varies, it is necessary also to vary the number of trains in order to properly and economically supply the mixer. The locations of passing sidings must accordingly be changed from time to time. It is generally cheaper to Change the location of a siding a quarter of a mile, than it is to allow the delay caused by the improper location to increase the running time of trains so that the required number of batches can not be delivered to the mixer. Of course, it is frequently impractical to locate sidings exaotly where the train schedules require them to be because of narrow shoulders, but this can often be easily and cheaply corrected by means of a small amount of cribbing. In any event an attempt should be made to approximate the correct location as closely as possible. As a rule no movement of a siding of much less than a quarter of a mile is necessary or justified. Steep grades are sometimes surmounted by placing passing sidings at the top or bottom, and uncoupling the locomotive from the empty train to assist the loaded train up a grade. This practice will occasionally avoid the purchase of additional motive power and in such a case might be justified, even though the location is not the correct one according to the schedule. If locating sidings at the top or bottom of a grade should so derange the train schedule as to reduce the output of the mixer, the question of whether it is less expensive to permit this or to purchase a booster locomotive oan only be decided after proper consi- deration of all factors peculiar to the job* Perhaps the best method of determining the location of passing sidings is the graphical method, shown in the accompanying graphs. The data on these prints apply to a two mixer plant supplied from one material yard, operating on what is known as a balanced haul. The time of leaving the material yard, arriving at the mixer, etc* is determined from a schedule such as that shown on page 48. The length of haul varies from 2 miles to 6 miles, and the locations of passing sidings are determined by the intersection of time ourves for the various trains. Graph #1, which applies when both mixers are at the 4 mile point, indi- L 50 cates that returning train #1, serving mixer #1, encounters outgoing train #2, serving mixer #1, at a point about 2-5/8 miles from the material yard. Theoret- ically train #1, serving mixer #1, encounters train #1, serving mixer #2, at a point about 3-3/8 miles from the material yard, but inasmuch as the trains serving eaoh mixer branch off at the 2 mile point this meeting in reality never occurs. Further on we see that train #1, serving mixer #1, encounters train #2, serving mixer #2, train #3, serving mixer #1, and train #3, serving mixer #2, at points approximately 1-3/4 miles, 1 mile, and l/4 mile from the material yard respectively At each of these points a passing siding is required, though the l/4 mile siding is so close to the material yard that the siding at the material yard will probably suffice. Proceeding in a similar manner we find that with mixer #1 at the 6 mile point and mixer #2 at the 2 mile point, and with mixer #1 at the 5 mile point and mixer #2 at the 3 mile point, that additional sidings, or sidings at different locations, are required. When two mixers are supplied from one material yard located some dis- tance from the road under construction, the small changes in siding location re- quired on the "dead haul" road need not generally be made. As a rule if the sid- ings along the "dead haul" road are located at the proper points for serving the mixers at the points of average haul, these locations are sufficiently correct for the other hauls involved. The sidings along the road tinder construction, how- ever, should be changed from time to time, as occasion demands. As a rule sidings must be placed approximately a mile apart on a light railway line serving one mixer, with a passing siding at the mixer itself. When two mixers are supplied by one line of track, as on a road leading from the material yard to the road under construction, approximately twioe as many sidings are needed as when but one mixer is used. The application of the method of locating sidings described in the fore- going in case only one mixer is to be supplied from the material yard, is a simple matter. A preliminary study should be made to determine the proper location of sidings for the entire job, with the haul varying by 1 mile intervals from the minimum to the maximum. As the haul from the material yard to the mixer changes, sidings can be shifted accordingly to the points previously determined. Practical common sense must always be used in applying this method of siding looation, for it is apparent that a change in the size of trains or the speed of operation will necessitate corresponding changes in the location of sid- ings. A study of the passing siding problan in the manner indicated in the fore- going, however, should do much to eliminate haphazard operation of trains and to insure the maintenance of proper schedules. ■- y I f \ - A7/'xcr ^2. /V/‘xcr S/d/'/r^ M/'xcr y-" v.::: . — ;a^ ., *S rf/dc r S/W/ntj /*7oAer/*/ 'Yard. h S/c /Z/ i^s &/ 5/D//V& jLOC/f 7“/ or/ for 3 OTA/ /+7/X.FXS A ?T Fo//VT OF F/EFFGE FFUJL. IHHH 77m or Zeav/na &no7 F 7^0 7*7* 7/er/a/ y#ro/. *S*€ ScAea'c/ /e /v'ft / &s>j ss-z / 'rc xcr S/d/ay tfsxer S/X/rn. M S/gf/aa &/ Wafer/#/ faro'. 3/D//V& £ 0C/1 7V 0SV far /*7/XJE/Z #/ XT’ S W/^3 /V//^7* ^*7*f /y7/X£j? *Z *7” 3 /*7/JL3 ^a//YT UM 7 ~/‘/? 7 c af /.eav/aj *7/7 o' fc/r /7 fo A 7 a fe/^/a/ fas'*/. +fee •J’c/fe a/a/c A^*- 3 <5* /=?£>* /V-g- 3 51 CHAPTER VIII. PLAN OF OPERATION It is extremely difficult, if not impossible, to outline a general plan of operation in highway construction, because local conditions vary so greatly . Some of the more conmon conditions encountered and plans of operation employed will be described, however, in order to illustrate the application of a road building plant to changing conditions. The application of both a complete railway plant and a combined light railway and motor truck plant, will be consi- dered. Under the subject of a complete railway plant, we will consider the following cases: One mixer plant, unloading point at one end. One mixer plant, unloading point near middle. One mixer plant, stone at one end and sand at the other. Two mixer plant, unloading point at one end. Two mixer plant, unloading point near middle. Two mixer plant, unloading points at each end. A job suitable for a one mixer plant with the unloading point at or near one end, is one which is frequently seen in practice. The best plan of operation on such a job is to start grading at the end of the road nearest the material yard, and to continue grading operations straight thru to the other end. As soon as a few hundred feet of subgrade are ready, mixing operations can be started and carried on continuously to the other end. The fact that the laying of concrete can be begun at the point of minimum haul, is one of the big advantages of light railway haulage. Not only is delay due to waiting on the completion of grading eliminated, but concrete and grading operations can be carried on simul- taneously. Moreover the most profitable portion of the concrete, the short haul portion, is done first, and this, combined with the simultaneous performance of concreting and grading operations, insures a large payment from the state early in the life of the job. The working capital generally so urgently needed at the beginning of a job, is thus provided. Two methods of handling a job suitable for a one mixer plant with the unloading point at or near the middle of the job, are in general use. One method is to start grading operations at the point nearest the material yard, and work towards either end of the road. As soon as a few hundred feet of subgrade have been prepared mixing operations are started, and follow closely behind the grading. Y/hen the mixer reaches one end of the job it is brought back to the point where it first started, and is then operated towards the other end. All of the track used in the first half is removed, and relaid for use on the second half. This plan permits simultaneous performance of concreting and grading operations, with the attendant advantages pointed out in the preceding paragraph. It is necessary, how- ever, to bring the mixer back around the concrete already laid after it reaches the end of the road, in order to permit it to proceed from the point where it first started to the other end. In the absence of suitable side roads,, the operation of bringing the mixer back might prove to be impossible or extremely difficult without considerable delay. Where conditions are such that to move the concrete mixer from one end 52 of the road back to the point where it first started is very difficult, or im- possible, the best method will be to start the mixer at one end of the road and operate it straight thru to the other. The disadvantage of this plan is that the laying of concrete must be started on the most expensive portion of the road, the long haul portion, while the organization is inexperienced and the track is not well bedded. It is frequently necessary, also, to delay concrete operations until all of the grading between the material yard and one end of the road is completed. One of the big advantages of starting the mixer at the point of minimum haul, aside from the large payment received from the state early in the life of the job, is that the organization is experienced by the time the most difficult portion of the work, the long haul portion, is reached. By this time,also,all of the track has been in place for some time, and is well bedded and surfaced. When the mixer is started at the point of maximum haul, on the other hand, not only must the inexperienced organization do the most difficult portion of the work first but it must operate over a newly laid track on which maximum speed cannot be attained for some time. It behooves a contractor, therefore, to weigh carefully the advantages and disadvantages of each plan. In general the plan of starting the mixer at the point of minimum haul is preferable, and should be followed if at all practical. Either of the foregoing plans of operation apply whether the material yard is adjacent to the road under construction, or is located a mile or two to one side, or whether the material yard is exactly at or opposite the center of the job, or is closer to one end than to the other. If the material yard is located at, or opposite, the quarter or third points, the second of the two foregoing plans possess less disadvantages than if the material yard is at, or opposite, the oenter of the job, for in such a case the delay in starting concreting operations, due to waiting on completion of the grading, is considerably reduced. Sometimes stone must be received at one end of a job and sand at the other, while cement may be obtained at either or both ends. Such a situation, while about the most difficult in highway construction, can be more easily handled by light railway haulage than by any other method. Perhaps the best way of illus- trating the operation of such a job, is by describing an operation planned in Pennsylvania in 1920. A concrete road 10 miles long was to be constructed in an entirely new location, through very rugged country, in which the grading, mostly shale, averaged some 15,000 cubic yards per mile. The lowest bid received was about $105,000 per mile, which gives some idea of the character of the work in- volved. Sand and cement were available at the railway at the lower end of the job, while stone was to be obtained by opening up a quarry near the upper end of the road. The sketch below shows a straight line layout of the road. / 53 On a job of this kind it is necessary first of all to complete the grading, inasmuch as it is impossible to haul material from one end to the other until this is done. The amount of grading on this road is sufficient to keep two steam shovel outfits busy during an entire working season, though it might be possible to do a good deal of the grading in the winter time if the contract was awarded in the fall. After the grading was completed, in case any method of haul- age other than light railway was employed, it would be necessary to place on the subgrade all the stone required, before mixing operations could be started. The mixer would then be started at the point of the road nearest the stone supply, and sand and cement hauled out as required. It is obvious that once the laying of concrete had begun, it would be impossible to haul past the uncured concrete by any other method than light railway in case additional stone was needed to re- plenish a shortage. The difficulty of distributing just the proper amount of stone is obvious, especially in view of the fact that the subgrade must be trimmed by hand and the wheels of the vehicles hauling material will out up the subgrade considerably. In practice a surplus of stone would probably be placed on the sub- grade, in order to prevent the likelihood of a shortage and delay in concreting. This surplus would then be wasted on the shoulder of the road from time to time, because it would be uneconomical to stop the mixer in order to permit of salvage. Even if the material thrown on the shoulder of the road could be salvaged when the pavement was completed, the cost of picking it up and shipping it to another point would be more than the material is worth. Not only would this method of operation involve a considerable wastage of stone, but to haul sand and cement such a long distance over the subgrade, obstructed as it is by the stone, would be very diffi- cult. On this particular job there were no side roads, and in case it should be- come necessary to haul stone to replenish a shortage, it would be necessary to suspend the laying of concrete until all of the pavement already laid was suffi- ciently cured to carry traffic, In case any other method of haulage than light railway were used. The combined light railway and motor truck method of operation was re- commended on this job, renting the motor trucks very cheaply from the state. With this plan of operation, as with any other, it was necessary first of all to com- plete the grading. Inasmuch as bids were asked in the early spring, the con- tractor planned to devote all of the first season to grading by means of two steam shovels. Just before freezing weather set in, he planned to drag the road so as to put it in fairly smooth condition for hauling. During the winter time material was to be hauled by motor trucks from the railroad and distributed in piles, each pile containing sufficient sand to build one-fourth to one-half mile of road, depending upon the room available. The mixer was to be started at the end of the road nearest the stone supply, and about two miles of light railway track laid on the shoulder. Until the concrete mixer reached the end of the track, stone could be loaded directly into batch boxes at the quarry and carried by the train to the mixer. As the train passed a sand pile. It would take on the proper amount of sand and cement, which had previously been placed there. The sand was to be loaded into a small portable bin by means of a bucket elevator and a small power scraper, and was to be charged directly into the batch boxes as they passed underneath on their way to the mixer. As each sand pile was exhausted,the bin would be moved on to the next one. By the time the mixer reached the end of the track, a certain amount of the concrete would be sufficiently cured to carry traffic. Motor trucks would then be used to haul stone from the quarry over the finished pavement as far as specifications permitted, dumping the stone on the pavement near a small port- able bin. This bin would be equipped with a bucket elevator and a small power scraper, in a manner similar to the sand bin. The light railway trains would thus pass under the stone and sand bins in succession, and take on the proper amounts for each batch. As the concrete hardened the stone and sand bins would be advanced « V f i 54 periodically, and the track no longer required in the rear picked up and relaid in advance of the mixer. If desired, the hauling of sand could "be postponed until shortly before the laying of concrete began. Cement would be hauled out and stored at each sand pile just in advance of the mixer. In case an improper amount of sand was stored in a pile, this method of operation would enable the supply to be readily replenished. The waste of stone, involved in the method of operation des- cribed in the preceding paragraph, would be avoided by the combined light railway and motor truck method. With a two mixer plant, we can so plan the operation as to produce what is known as a balanced haul. This consists of starting one mixer at the point of minimum haul, and the other mixer simultaneously at the point of maximum haul* It is obvious that if these mixers are of the same size, they should operate at approximately the same rate of speed. The amount of equipment released by the machine which started at the point of maximum haul, as its haul decreases, is just about sufficient to make up the shortage constantly occurring at the mixer whose haul is increasing. If, then,we provide sufficient rolling stock for two mixers based upon the point of average haul, we will have sufficient equipment to supply both mixers at all points by transferring from one to the other as occasion arises. With a one mixer plant, we are confronted by the problem of deciding as to just what length of haul the rolling stock should be proportioned for. If we proportion it for the point of average haul we will have an insufficient amount when the haul exceeds the average, while if we proportion it for the point of maxi- mum haul we will have a surplus as soon as the haul is less than the maximum. By operating two mixers on a balanced haul, however, all of the equipment will be kept busy at all times. Sometimes it i6 necessary or desirable to use two mixers on a road, where the unloading point is located at one end. These mixers can be operated on a balanced haul in the following manner: Start both mixers at the center of the road, operating them away from each other toward opposite ends of the job. Lay a line of track for each mixer on opposite shoulders of the roai. If these mixers are of the same capaoity, they should operate at about the same rate of speed. As one mixer approaches the material yard, and its length of haul decreases, it will release track and rolling stock sufficient to make up the constantly occurring shortage at the other mixer, which is operating away from the material yard. This operation is continued thruout the job, the surplus equipment released by one mixer being immediately put into service in supplying the other. This plan of operation required but slightly more track than if only one mixer is employed. It does, however, involve the laying and removing of 50 per cent greater mileage of track, because a line of track equal to half the length of the road is first laid on each shoulder after whioh the track on one shoulder is extended to the far end of the road. The sketoh below illustrates an operation such as we have in mind. 55 A job suitable for a two mixer plant with an unloading point at or opposite the center of the road, is one frequently seen in practice. Such a job is well adapted to the application of a balanced haul. The sketch below illus- trates a 10 mile job with the unloading point opposite the center and 2 miles away. Start one mixer at the point of intersection of the "dead haul" road with the 10 mile road, the point of minimum haul, and the other mixer and the point of maximum haul at the end of the road* Operate both mixers simultaneously in the same direction, transferring equipment from one to the other as occasion demands* A balanced haul can be applied very nicely to a job with unloading points at each end, by starting one mixer at the middle of the job and the other at one end. The mixers should be operated simultaneously in the same direction,and should be supplied from separate material yards* The layout of such a road is shown in the following sketch. Ai/ce or 7-rrcx — 0s* 7-sV^rcj? — * The plan of operation outlined above will require an amount of track but slightly greater than half the length of the road, for as equipment is re- leased from the mixer which started at the middle, it is transferred to the mixer which started at one end. This plan of operation requires less track than where all the material must be hauled from one end, and the mileage of track to be laid and removed is equal to the length of the road. The operation of a two mixer plant with a material yard at each end of the road involves less track laying and less ton mileage than where all material must be hauled from one end, but it necessitates the operation of two material yards. Whether it is more economical to establish and operate two material yards than to haul all material from one end, depends upon the decrease in the ton mileage resulting therefrom and must be left to the individual judgment of the contractor. As a rule, unless the cost of establishing the second material yard is excessive, it will generally be found that the saving due to the decreased ton mileage and the decreased amount of equij> ment required will justify two yards. Still another method of operating a two mixer plant on a balanced haul when all material must be hauled from one end, is by starting one mixer at the far end of the road and the other at the end nearest the material yard* Both mixers should be operated towards the center of the job, and as equipment is released 56 by the mixer which started at the far end it is transferred to the mixer which started at the near end. This plan possesses no particular advantage over the plan previously described, of starting both mixers at the center of the job and working them away from each other. Track for supplying each mixer should prefer- ably be laid on opposite shoulders, though it is possible for a contractor of good organizing ability to supply both mixers from one line of track. If he can supply both mixers from one line of track, he will save the cost of laying and removing an amount of traok equal to half the length of the road. In all of the preceding discussion we have considered only the complete railway plant. The combined light railway and motor truck plant can be applied in much the same way. On a job suitable for a one mixer plant with the material yard at one end, the best plan of operating a combined light railway and motor truck plant is to start the mixer at the point of minimum haul, as soon as a few hundred feet of subgrade have been prepared. If the material yard is located directly at the end of the road, material can be hauled by light railway until the mixer reaches the end of the l-l/2 miles of track conmonly employed in this typeof plant. If the material yard is located some distance from the beginning of the job, material can be hauled in batch boxes on motor trucks to the beginning of the job, where it can be transferred to the railway, by means of a portable derrick, for haul to the mixer. By the time the mixer reaches the end of the railway track a certain amount of the pavement already laid will be sufficiently cured, according to specifications, to carry traffic. While the mixer may only operate 20 days per month, or say two-thirds of the time, Sundays and holidays and other days during which the mixer does not run are just as valuable for curing concrete as are work- ing days. Each day, as another section of concrete comes of age, the transfer point is advanced by dragging forward the portable derriok, and the track no longer required in the rear is relaid in advance of the mixer. If the mixer operates at an average of 400 feet per day, the transfer point can be advanced at approximately the same rate daily. The advantage of this plan of operation, due to the fact that concreting and grading can be carried on simultaneously, has been previously pointed out* A road with the unloading point at or opposite the middle of the job, or some point between the middle and the end, can be handled in the manner out- lined in the previous paragraph. The mixer can be started at the point of minimum haul and operated away from the material yard towards one end, after which it is brought back and operated towards the other end, or it can start at one end of the job and operate continuously thru to the other end. The method of handling a job suitable for a one mixer plant with sand and stone at opposite ends, by means of a combined light railway and motor truck hauling plant, has previously been outlined in describing a 10 mile road in Penn- sylvania. A two mixer plant with the unloading point at one end of the job, can be supplied by means of a combined light railway and motor truck plant in the following manner* Start one mixer at the point of minimum haul and the other mixer at the half way point, supplying 1-1/2 miles of track to the mixer at the point of mini- mum haul and a length of track equal to half the length of the road plus I-1/2 miles, to the mixer at the half way point. If the unloading point is located exactly at the end of the job, the mixers can be supplied ty means of light railway haulage entirely until they reach the end of their respective tracks, if the unloading point is some distance from the beginning of the road, material can be hauled in batch boxes on motor trucks to the beginning of the road and there J . 57 transferred to the railway. By the time the mixers reach the end of their respective lines of track, a portion of the concrete already laid by the first mixer, operat ing at the minimum haul, is sufficiently cured to carry traffic. From then on the regular method of operating this type of plant is followed, advancing the transfer point as the concrete hardens and removing track in the rear and relaying it in advance of the mixer. The plan of operation just des- cribed will require almost as much track as if a complete railway plant were used, and there is, therefore, no particular merit in it. If the job is large enough to require two 14-E paving mixers and it is still desired to employ the combined light railway and motor truck plant, it would be preferable to employ a 28-E paver rather than two 14-E’s. A 28-E operated on the combined principle with 2 miles of track, would work very nicely. If the unloading point is at, or opposite, the middle of the job, and it is desired to use two paving mixers supplied by the combined light railway and motor truck plant, the best plan would be to start both mixers at the point of minimum haul and operate them away from each other toward opposite ends of the road. This operat ion, in effect, is exactly the same as if two separate jobs were operated with an unloading point at the end. In the case of a job with an unloading point at each end, a two mixer plant can be operated by the combined light railway and motor truck method by starting the mixer at the points of minimum haul and operating them towards each other so that they will meet in the middle. The regular method of operation with a combined plant will be in effect here. The fundamental idea underlying operation with a light railway haulage plant, or a combined light railway and motor truck plantain highway construction, is to start the mixer at the point of minimum haul. In case of a two mixer plant start one mixer at the point of minimum haul and the other at the point of maxi- mum haul, so as to secure a balanced haul. The laying of concrete can then be started as soon as a few hundred feet of subgrade have been prepared, thus elimi- nating the delay that generally occurs in placing concrete due to the necessity of waiting for completion of the grading,when any method of haulage other than light railway is used. Not only is this delay eliminated, but the laying of con- crete and grading can be performed simultaneously. The most profitable portion of the concrete, the short haul portion, can be done first, and this, in conjunc- tion with the simultaneous performance of concreting and grading, insures a large payment from the state early in the life of the job. The working capital, always so badly needed at the start of a job, is thus provided. By starting the mixer at the point of minimum haul the organization is experienced by the time the most difficult portion of the work, the long haul portion, is reached, and the track is well bedded. ViTith either the complete railway system or the combined light railway and motor truck system, all hauling is done over steel rails or improved roads. Delay due to rain should thus be reduced to a minimum. Of course, when the unload- ing point is located some distance from the road under construction and the com- bined system is used, the road leading from the unloading point is not always of the best. Operation over this road, hov/ever, is no more serious than if some other method of haulage were used, and the cutting up of it is by no means as serious or costly to the contractor as is the cutting up of the subgrade. 58 CHAPTER IX. HAULAGE EQUIPMENT REQUIRED. In this chapter we will consider all of the light railway rolling stock and the necessary amount of track and passing sidings required, as well as all motor truck equipment used in conjunction with the light railway in a combined light railway and motor truck plant. The rolling stock and track required, varies not with the length of the road but with the length of haul. In case of a 10 or 12 mile job, it is generally possible to establish unloading points so that not more than 3 or 4 miles of track are needed. When the unloading point is located at one end, however, it is nec- essary to use an amount of track equal in length to that of the road, except where the combined system of haulage is employed. In proportioning the amount of rolling stook, except in case of a balanced haul, we are confronted with the problem of basing our computations on the average haul, on the maximum haul, or on some point in between. If we adopt the average haul as the basis for the rolling stock required, we will have an insuffi- cient amount as soon as the haul exceeds the average. The capacity of the haulage plant between the points of average and maximum haul, in such a case, is insufficient to supply the mixer at the proper rate. If we base the amount of rolling stock upon the maximum haul, on the other hand, we will have a surplus on all hauls be- low the maximum. This will insure operation of the concrete mixer at full capa- city at all times, but the method is uneconomical due to the surplus rolling stock which is idle a good deal of the time. Experience indicates that a length of haul about half way between the average and the maximum, is the proper one upon which to base the rolling stock required. In other words, when material must be hauled from one end of a job to supply a single mixing plant, proportion the rolling stock upon a basis of three-fourths of the maximum haul. Experience has demonstrated that an average speed of 6 miles an hour for both loaded and empty trains, is the proper speed to use in determining the amount of rolling stock needed to supply the mixer. In rolling country, where the down grades balance the up grades fairly well in both degree and length, this average speed of 6 miles per hour can also be used in making rolling stock computations. In special cases, where the preponderance of asoending grades is opposed to the loaded trains, it might be necessary to compute the weighted mean speed as des- cribed in a previous chapter. In operating a light railway plant some contractors prefer to keep the locomotive attaohed to the train,while it is being unloaded at the mixer and loaded at the material yard. Other contractors prefer to detach the locomotive and immediately pick up another train. The decision as to which method to adopt de- pends upon local conditions, and frequently both methods are used in the same job. Where long trains of 10 to 20 cars are used, it is generally more economical to detach the locomotive at the mixer and return at once to the material yard, in such a case the train at the mixer is moved by means of a team of horses, the road roller, or by hand. Where small trains of only 3 or 4 cars are used, it is gen- erally preferable to keep the locomotive attached to the train at the mixer during the unloading process, except where the split train method is used. Even in hilly country it is seldom necessary to use such small trains, except for a small pro- portion of the time* 59 LOCOMOTIVE ATTACHED TO TRAIN AT MIXER The question of whether to detach the locomotive from the train at the material yard during the loading process, is governed by the same conditions as at the mixer. When the tunnel system of storage is used, the switching of the train at the material yard is frequently effected by means of a small hoisting engine set at one end of the tunnel • Sometimes an endless cable is passed thru the tunnel, and around sheaves so as to pass outside of the material pile. A team hitched to this cable on the outside can then be used to shift the train in the tunnel. Many tunnels are constructed on a slight grade, about one-half of 1 per cent, so that the shifting of the train is facilitated thereby. Experience has shown that where the tunnel system of storage is used, an allowance of one minute per batch is sufficient for completely charging a train at the material yard. To load a 10 car, 20 batoh train, therefore, will require 20 minutes, and in computing the running time of a locomotive, which remains attached to the train during load- ing, this allowance should be made. When material is hauled from one end of a job to a one mixer plant, the rolling equipment is generally based upon three-fourths of the maximum haul. On all hauls less than three-fourths of the maximum, a surplus of rolling equipment will be on hand, and during this period it is generally feasible to keep the loco- motive attached to the train at the mixer during the unloading process, if desired. Later on, as the haul increases to the point where time is not available for keep- ing the locomotive at the mixer or at the material yard during the unloading and loading process, the locomotive can be detached from the train at one of these points. Still later on as the length of haul increases, it will probably be nec- essary to detach the locomotive from the train at both the mixer and the material yard. If the locomotive is detaohed at the mixer and at the material yard, fita additional train of cars must be provided at each point. For instance, if only 3 locomotives are in use and they remain attached to the trains during all opera- tions, but 3 trains are required. If the trains are dropped at the mixer and the material yard, however, an additional train must be provided at each of these points, making 5 all told. In considering the question of detaohing locomotives at the mixer and at the material yard, the cost of additional cars and the cost of switching by means of team, hoisting engine, or by hand, must be compared to the 60 oost of the additional locomotives which might he required and their cost of oper- ation. In the majority of cases it is more economical, as a rule, to detach the locomotives from the train at the mixer and the material yard, than it is to keep them there during the process of unloading and loading. Where 6 ton locomotives are used for hauling, 3 ton machines are sometimes provided for switching trains at the mixer and at the material yard. In charging the mixer by means of batch boxes carried on oars, it is necessary to move the car for each batch so as to permit clearance when the mixer derrick picks up a box. In level country the problem of moving cars is not serious, and is almost always done by hand by detaching and moving one car at a time. A single horse is sometimes used to haul the empty cars to the switch, which is never more than a few hundred feet from the mixer. As a rule, however, the passing siding is kept close to the mixer, not more than one-half or one day’s run away, and the locomotive arriving with the loaded train has plenty of time to switch the empty. SWITCHING- CARS WITH A HORSE 61 PASSING SIDING NEAR MIXER In hilly country the problem of switching cars at the mixer is somewhat more difficult than in level country/ due to the grades. When the locomotive is detached from the train at the mixer, the train should be left standing on the up-hill side of the mixer. Cars used in hilly country are generally all equipped with brakes, and they can be let down to position near the mixer either singly or in trains. Single cars can easily be controlled by means of their brakes, or by means of a stick of wood pressed against a wheel. After being unloaded the cars are dropped down grade some distance, where they are again formed into a train at a siding. When it is desired to switch entire trains on steep grades in order to permit unloading, some other method of control than brakes must generally be used. This is due to the fact that the brakes on each car operate independently of the' other,, and there is no means of controlling all the brakes in a train as a unit. A method frequently used, in such a case, is to "snub" a rope around a tree or an anchor post at one side of the track, pass it thru a sheave in the center of the track, and attach it to the train. Still another method of shifting trains as a unit on grade, is by means of a line attached to the road roller. The passing sid- ing should always be placed on the down grade side of the mixer, so as to permit the empty cars to be coasted down to the siding and there formed into a train. Consider now a road 5 miles long, with an unloading point at one end. The amount of track required is equal to 6 miles, plus a certain amount for passing sidings and for the material yard. The amount of track needed for passing sidings cannot be determined until the number of sidings are known, and this in turn de- pends upon the number and size of trains. As a rule, however, a passing siding every mile is sufficient where but one mixer is to be supplied. The length of passing siding depends upon the size of trains. The overall length of a car from coupling to coupling is about 8 feet, so that a 10 car train with a locomotive will require about 90 feet in the clear. To allow a little extra we will provide 105 feet of clear track in the siding, inasmuch as this is exactly equal to 7 sec- tions of track. In case it is desired to determine the exact number of sidings necessary, a time schedule should be computed and a graphical determination made from it. In the case in point, we will provide one passing siding at the mixer and 4 along the line. At the mixer we will provide 795 feet of track, inasmuch as this is exactly equal to 53 sections. The total amount of track provided on this job, therefore, will equal 5.25 miles. JJ . 62 The switch and a special straight and curved section required to fonn one end of a passing siding, is known as a half turnout. Two of these are re- quired at each passing siding, while at the material yard we will provide 4 more. This makes a total of 14 half turnouts all told on this job. Details of a half turnout will be found on page 24 of bulletin #29-D of The Lakewood Engineering Company, which is included in the appendix. Special curved sections 7-l/2 feet in length of 30 foot radius are pro- vided, 6 of which will subtend a central angle of 88 degrees and 45 minutes. Curves of lesser degree can be obtained by using fewer curved sections. The number of curved sections to be provided on a job depends upon local conditions. In this case we will assume one 90 degree bend in the road, and at the material yard 3 more It is necessary, therefore, to provide about 25 curved sections for this job. The rolling stock will be based upon a haul of three-fourths of the maximum, or 3*75 miles, and upon a speed of 6 miles per hour. An allowance of 5 minutes will be made for switching trains at the mixer, and th& same amount of tine at the material yard. The controlling grade will be assumed at 3 per cent, en- abling a 6 ton looomotive to haul a train of 7 to 8 cars, each carrying 2-4 bag batches of material for 1-2-3 concrete. Such a oar will weigh 3.4 tons, with sand at 3,000 pounds per cubic yard, stone at 2,700 pounds per cubic yard, and cement at 374 pounds per barrel. The running time of the train, based upon the foregoing data, will be 85 minutes per round trip on a 3.75 mile haul. This is equivalent to 7 round trips per 10 hour day, enabling each locomotive to deliver 98 batches to the mixer. Three locomotives are, therefore, required to supply the mixer with 300 batches per day. Five trains of 7 cars eaoh, or a total of 35 cars and 70 batch boxes, must be provided. The amount and cost of the railway equipment needed on a job of this kind, based upon prices in March,1921, is as follows: EQUIPMENT 5^: miles straight track @ $6,318.40 14 half turnouts @ $150.00 25 curved sections @ $13.95 35 batch box cars @ $115.00 70 batch boxes, 25 cu.ft. cap. @ $71.20 3-6 ton gasolene locomotives <3$4, 600.00 2 platform cars, general utility, $ $415.00 COST WEIGHT $33,171.60 637,560 lbs 2,100.00 15,190 *t 348.75 4,625 it 4,025.00 38,500 tt 4,984.00 28,000 tt 13,800.00 37,300 tt 830.00 4.000 « $59,259.35 765,175 lbs, The sketch below shows a road on which it is desired to operate two paving mixers, supplying them by means of a complete railway haulage plant from an unloading point at one end. The mixers will be operated on the balanced haul principal, by starting at the center of the road and working away from each other toward each end. Inasmuch as these mixers are of the same size, the rate of oper- ation of each should be about the same. The equipment released by the mixer oper- ating on the decreasing haul, therefore, should be just about sufficient to pro- vide for the shortage at the mixer operating on the increasing haul. Rolling stock provided for two mixers at the point of average haul, therefore, should be sufficient to keep each mixer fully supplied at all times by transferring from one to the other as occasion requires. 63 The amount of track required for the two mixer plant, is slightly more than twice that for the one mixer plant previously considered. This is "because a small amount of extra track is provided / to take care of delay in moving equip- ment from one mixer to the other. We will allow an extra quarter mile for this purpose, making a total of 10-3/4 miles required for this job. The rolling stock will be based upon the full haul of 5 miles, rather than three-fourths of 5 miles as in the single mixer job. Five passing sidings will be provided for each mixer, making a total of 24 half turnouts, including 4 at the material yard. Assuming one 90 degree bend in the road and 3 at the material yard, a total of 30 curved sections are needed. The running time of a locomotive per round trip on the 5 mile average haul at 6 miles per hour, allowing 5 minutes for switching trains at the mixer and 5 minutes at the material yard, is 110 minutes. This is at the rate of 5 round trips per 10 hour day. Assuming an 8 car train, each locomotive will deliver 80 batches per day to the mixer so that 4 locomotives are needed to supply at least 300 batches. Six trains of 8 cars each and 16 batch boxes must be assigned to each mixer, and the total amount of equipment required for two mixers would be approximately twice that required for one. Inasmuch as 4 locomotives and 6 trains possess somewhat greater hauling capacity than is required by one mixer, we will provide a total of 7 looomotives and 11 trains for two mixers instead of doubling the amount required for one. In addition to the equipment listed in the foregoing, it is necessary to provide at least 2 double truck platform cars for the purpose of moving track from one mixer to the other and for general utility haulage. The oost of the plant outlined for the two mixer job shown in the sketch above, can be computed as in the previous example. When mixers are operated on the balanced haul they can be operated at a full rate of speed at all times, due to the fact that track and rolling stock can be transferred from one to the other as desired. Further- more, the rolling stock is kept busy at all times, and the problem of a surplus or a shortage of haulage equipment is eliminated. The investment in haulage equip- ment per mixer is less when mixers are operated on a balance haul, than where but one mixer is to be supplied. £his is obvious when we consider that haulage equip- ment for a one mixer plant is based upon a length of haul equal to three-fourths of the maximum, while haulage equipment for a mixer operating on a balanced haul is based upon the average haul. A two mixer p]ant with the unloading point near the middle of the job and immediately adjacent to or some distance from the road, can be operated very nicely on the balanced haul principle. Less track is required in such a case, then where all material must be hauled from one end. The most expensive type of operation is that where all material must be hauled from one end of the job. If possible an unloading point should be secured as near the center of the job as conditions will permit, for the investment in haulage equipmait, as well as the ton mileage, is thereby considerably reduced. 64. GENERAL UTILITY PLATFORM CAR The fundamental idea to be kept in mind in operating mixers upon the balanced haul principle, is that equipment should be based upon the average haul* The amount of equipment required for two mixers is, therefore, approximately twice that required for one. The investment in haulage equipment per mixer is less in a two mixer plant operating upon a balanced haul, than in a one mixer plant. The general characteristics of a combined light railway and motor truck haulage plant for highway construction, have already been described. The funda- mental idea of this plan of operation is to haul material by motor truck over that portion of the oonorete which, according to specifications, is suf f iciently cured to carry traffic, and to transfer material at this point to a light railway train for haul past the uncured concrete to the mixer. A good organization with an adequate supply of materials, should lay about 400 feet of 18 foot concrete road per 10 hour day with a 14-E mixer. In a normal season about 20 working days per month should be obtained, and at this rate 14 working days should be obtained during the 21 day curing period which most states require before permitting traffic on the concrete. At a rate of 400 feet per day, the mixer should lay about 5,600 feet of road in 14 working days. The minimum amount of track that must be provided for hauling material from the transfer point to the mixer is, therefore, 5,600 feet 4 To allow for failure to move up track promptly, slow curing of concrete, or for more than 14 working days during the 21 day curing period, it is wise to provide 1-1 Jz miles of track for a oombined light railway and motor truck haulage plant. Two passing sidings, one at the transfer point and one near the mixer, will be sufficient, so 4 half turnouts must be provided. The number of curved sections will depend upon each individual road, but in this case we will assume 10 sections to be sufficient. A 5 ton motor truck will carry 4 batch boxes, each containing properly proportioned materials for a 4 bag batch of the mixture generally specified in concrete road work, while a 3-l/2 ton truck will carry 3 such batches. A suffi- cient number of batch boxes must be provided to equip the maximum number of trucks needed at the maximum haul. 22 " 65. BATCH BOX HAULAGE WITH 3-l/2 TON THJCK In determining the amount oaf motor truck equipment needed, a speed of 6 miles per hour loaded and 10 miles per hour empty is a good average over earth or macadam roads in fairly good condition* On hard surfaced roads, an average speed of 10 miles per hour for a 5 ton truck "both loaded and empty is about right. Experience has shown that an allowance of 5 minutes at the material yard for load- ing 4 batch boxes and 10 minutes at the transfer point, is ample. LOADING TRUCK, BATCH BOX HAULAGE SYSTEM / A7/z.£ Ck, - 4 . —A7/X3* /4- -£ & , C T. CT£>*s<0*37~.£ /?/&£. 4 ro//W 'y&rtD ' z^7- S7-/7^7- or 003 /£ - >// a ss or 7~rrcrzi. £OA73//V£D L/GttT /?/?/LW/7y /7/VO T/7UC/< 5ySJ-£/Y7. •I 66 TRANSFERRING BATCH BOXES FROM TRUCK TO CAES The sketch at the Bottom of page 65 shows the layout for a combined light railway and motor truck haulage plant applied to a 5 mile job, the unload- ing point for which is located 1 mile from one end. The best plan of operation is to start the mixer at the end of the road nearest the unloading point, as shown in the sketch. Loaded batch boxes will be hauled by motor truck to the beginning of the job, where they will be transferred to light railway cars by means of a small crane shown in the photograph above, or By means of a portable derrick shown in illustration below. PORTABLE DERRICK FOR TRANSFERRING BATCH BOXES The transfer point will be maintained at the beginning of the job until the mixer, which operates at about 1.E5 miles per month, is near the end of the track. By this time about half of the concrete laid is 21 days old. The transfer point will then be advanced as far as possible by moving up the portable derrick, and the track no longer required in the rear will be picked up and relaid in ad- vance of the mixer. This operation will be repeated each day, or every two days, as additional concrete comes of proper age to carry traffic. We will assume that the road between the material yard and the beginning of the job is not improved, so that an average speed of 6 miles per hour loaded and 10 miles per hour empty is all that can be expected from the trucks. At this rate, allowing 5 minutes for loading and 10 minutes for transferring, the round trip on the 1 mile haul will be performed in 31 minutes. This is at the rate of i i\ 67 19 round trips per 10 hour day, and inasmuch as each 5 ton truck carries 4 batches^ it will deliver 76 hatches per day to the transfer point. To provide a supply of 300 batches, will require the services of 4 trucks. The maximum haul for trucks will be l-l/2 miles from the far end of the road, or a distance of 4-l/2 miles. On the first mile of haul the loaded truck will average a speed of 6 miles per hour, and on the remaining 3-l/2 miles over the finished pavement it will average 10 miles per hour. On the return trip an average speed of 10 miles per hour should be attained thruout. Allowing 5 minutes for loading and 10 minutes for transferring, a total of 73 minutes are required per round trip on the maximum truck haul. At this rate a truck will make 6 round trips per day, delivering 32 batches to the transfer point. On the maximum haul, therefore, 9 trucks should suffice, making an average of 6 to 7 trucks thruout the job. On the motor truck portion of a combined light railway and motor truck haul, it is generally more economical for a contractor to rent trucks than to purchase them. He can then add trucks from time to time as needed. A contractor must distribute all his plant charges over a working season of only some 120 days, whereas a trucking company can distribute its plant charges over a period twice as long. For this reason the trucking company can afford to rent trucks at a smaller per diem rate, than the contractor can operate his own trucks for. Inasmuch as a maximum of about 9 trucks are required on this job and each truck carries 4 boxes, 36 batch boxes must be provided for the trucks. For contingency 4 more should be added, making a total of 40 in addition to those required by the railway cars. On the railway portion of a combined light railway and motor truck haul, the locomotive operates continually between the transfer point and the mixer on an average haul of about 1 mile. At a speed of 6 miles per hour, allowing 5 min- utes at the mixer and at the transfer point for switching purposes, 30 minutes are required by the locomotive to make a round trip. During this 30 minutes the mixer will consume about 15 batches of material, so that a train of 7 or 8 cars must be used. In case the grades are so steep that a train of only half this size can be used, it will be necessary to provide 2 locomotives. Each locomotive can then haul a train of 4 cars, or they can cooperate in hauling a train of 8 cars. Fewer EQUIPMENT 1 6^-ton gasolene locomotive 24 batch box cars @$115.00 48 batch boxes for cars @ $71.20 40 batch boxes for trucks @ $71.20 1st mile straight track @ $6,318.40 4 half turnouts @ $150.00 10 curved sections @ $13.95 1 platform car, general utility 3 car trains, can be used. In the case COST WEIGHT $ 4,600.00 12,500 lbs. 2,760.00 26,400 i» 3,417.60 19,200 it 2,848.00 16,000 It 9,477.60 182,160 n 600.00 4,320 n 139.50 1,850 It 415.00 2.000 ft $24,257.70 264,430 lbs. The cost of equipment shown in the foregoing table is the current cost in Maroh, 1921. 1 * 68 LOCOMOTIVE AT TRANSFER POINT TRAIN APPROACHING MIXER, COMBINED SYSTEM Sometimes material is hauled in tnilis: in dump body trucks, on the motor truck portion of a combined light railvgay and motor truck plant. In such a case material is dumped near a small portable bin at the transfer point, into which it is rehandled by means of a bucket elevator and a power scraper, a small crane equipped with a clam shell bucket, or a portable belt conveyor. The batoh box system of haulage is preferable to the bulk system, because not only are all pro- portioning operations concentrated at the material yard but a light derrick can be substituted for the expensive rehandling equipment necessitated at the transfer point by the bulk system. Sometimes it is necessary to employ the bulk system , where the sand, cement, and stone are obtained at widely scattered points. Even when the bulk system of haulage must be resorted to, the combined light railway and motor truck plan possesses big advantages over the method of dumping material on the subgrade or of charging the mixer direct from a truck. Sometimes the batch box system of haulage is objected to, on the grounds of the dead weight of the boxes. It must be kept in mind, however, that the batch 69 1 ■box system permits a platform truck or a plain truck chassis equipped with a light wooden frame, to be employed as haulage units. Hot only does this reduce the cost of rental or purchase of trucks, but it increases the number of units available. Four steel batch boxes of sufficient capacity to contain a 4 -bag batch of material for the mixtures commonly employed in concrete road construction, will weigh 1,800 pounds and cost about $280.00. The dump -body for a 5-ton truck will weigh about 2,000 pounds, and will cost about $800.00. In both weight and cost, therefore, the batch box system is superior to the dump-body, bulk-haulage system. TRUCK CHASSIS EQUIPPED WITH BATCH BOX FRAME Other equipment used in concrete road construction, is listed in the following table with both its cost and weight. The prices are those prevailing in March, 1921. The equipment as listed is that required for one mixing plant. The derrick at the transfer point would not be needed, of course, in case a com- plete railway hauling plant is used. 70 EQUIPMENT COST WEIGHT 1 14-E paver, with boom and bucket, batch transfer, l/2 caterpillar, and batch meter $ 7,925.00 25,400 lbs. 1 finishing machine 1,800.00 3,000 " 1 subgrade machine 600.00 2,300 " 2000 feet, 6" steel form @ $9.12 per 10 ft. sec. 1,824.00 17,600 " 1 double unit road pump 1,500.00 4,000 » 1 3/4 yard clam shell bucket 700.00 2,530 " 1 derrick at transfer point 1,200.00 At the material yard, traps are provided in the roof on the tunnel or in the "bottom of the bin for the purpose of loading hatch boxes. These traps are generally spaced every oar length, or approximately 8 feet apart in the t unn el. The type of trap manufactured by The Lakewood Engineering Company es- pecially for handling sand and stone, weighs 94 pounds and costs $23*50. Two inch diameter wrought iron pipe is the type generally employed in the water supply system for a 14-E or 21-E mixer plant. For a 28-E mixer a Z-l/z inch pipe should be used. Pipe smaller than 2 inch in diameter should never be used. Two inch wrought iron pipe weighs 3-2/3 pounds per foot and cost, in March, 1921, about $0.30 per foot. Union should be provided in the pipe line every thousand feet, with gate valves every quarter or half mile. Tees should be provided approximately 80 feet apart, for attaching the hose leading to the paving mixer. An expansion joint should be provided every half mile or so to take care of variations in the length of the pipe line. This is a very important feature, and should not be overlooked. The C. H. & E. Manufacturing Company, of Milwaukee, Wisconsin, manu- facture an eapansion joint which is quite commonly used, though most contractors prefer to make a home-made affair of a piece of hose or a short cross pipe 3 or 4 feet long. Complete illustrations and specifications of the equipment mentioned in this chapter will be found in the appendix. 71 CHAPTER X. MATERIAL UNLOADING- AND PROPORTIONING YARD. Of all the problems confronting the highway contractor, the problem of receiving, storing, and proportioning material is the most important. Some of the elements of this problem, notably that of receiving material, is largely beyond the contractor’s control, and is dependent upon railroad deliveries which are fre- quently erratic and unreliable. In order to avoid delay from this source, there- fore, the prudent contractor provides adequate storage facilities, and takes steps to insure a proper supply of material during the construction season by storing material during the inactive road building months. In the past the biggest handicap to storing raw material during the inactive season, was due to the large amount of working capital required. At the present time, however, most State Highway Departments have adopted the practice of paying monthly estimates on material, providing it is stored in large stock piles near a railroad. As a rule no payments are made for material distributed along the road in windrows, on account of the possibility for loss. This attitude of State Highway Departments affords an opportunity to practically all contractors to prepare themselves properly for quantity production during the construction season,by storing materials in the winter months. Payments on cement stored during the winter months are as yet not generally made, due to the perishable nature of the product. Some states, how- ever, notably Pennsylvania, permit contractors to store cement after the fifteenth of February, and make monthly payments on cement so stored. This reduoes the amount of time the cement is kept in storage, while it gives the contractor about two months to provide a reserve of cement. When bagged cement is used no payments are made for the bags, and the contractor is compelled to invest $>1.00 per barrel in this non-productive item. Bulk cement possesses a big advantage in this res- pect, inasmuch as no money is tied up in bags. Contractors are rather wary of storing cement for any considerable length of time, due to the danger of spoiling. Experience in the past justifies caution on their part. The storage of cement so as to prevent spoiling, however, is now better understood than it was in the past. If the cement house is so constructed as to keep out moisture, using tar paper on the walls and floor and storing cement so as to prevent the circulation of air, there is but little danger of spoiling. The great enen^ of cement is moisture, and inasmuch as air carries moisture every precaution should be taken to prevent its circulation. Cement should be piled so as to prevent the circulation of air thru it, and should be covered with building paper or canvas. Due to the difficulty of securing an adequate supply of material during the past two years, some contractors, especially those who were formerly engaged in railroad construction, have purchased and operated their own standard railroad equipment. This equipment was operated between the points of material supply and the job, in the exclusive service of the contractor owning it. In order to prevent loss of this equipment, or divert ion at a junction point, a man or two was gener- ally assigned to the task of keeping track of it. The railroad charged a certain amount for hauling material in this maimer, and reimbursed the contractor for the use of his equipment at the rate of about $0,006 per mile. <♦ * 72 A notable example of the use of privately owned standard railroad equip- ment in highway construction, was afforded by the Crittenden-Ozark road project in Arkansas in 1920. The equipment consisted of 105 Western air dump cars of 30 cubic yard capacity, which was operated from the gravel pit at Wittenberg, Missouri over the Frisco Railroad a distance of 170 miles to the job* At the unloading point material was dumped on each side of the track, which was jacked up from time to time so as to form a large embankment of gravel. This embankment at one un- loading point was 800 feet long and from 20 to 30 feet high at the highest point. The track was shifted and material unloaded by a gang of 14 men and 1 foreman, at a contract price of $0.20 per ton. Previous to adopting the embankment system, an Erie crane equipped with a 3/4 yard clam shell bucket was used for unloading material at a cost of $0.30 per ton. The saving in the cost of unloading the 287,400 tons of gravel, was thus considerable. The loaded oars were run in solid trains of 30 cars, each containing about 37 tons of material. The railroad charged $50*00 per loaded car for hauling, and returned the empty cars free of charge in mixed trains. The road district received the rental of $0,006 per mile from the railroad for the use of their equipment. Loaded trains left the gravel pit at Wittenberg at 6 o'clock in the evening, and arrived at Chaffee, a junction point 30 miles from Wittenberg, at midnight. At 9 or 10 o'clock the following morning, the loaded train was at the job. The work of switching and dumping the train of 30 cars required about 2 hours. The round trip of 170 miles, including switching, dumping, and loading, required 3 days. During the last week of November 1920, 217 cars were unloaded. The Morgan Engineering Company, of Memphis, Tenn. were in charge of this project, while the Industrial Track Construction Company, of St. Louis, Missouri shifted the track and dumped the cars for a contract price of $0.20 per ton. The cost of the air dump cars was somewhat over $300,000, and it is questionable whether the saving effected by this system is sufficient to com- pensate for the loss when these cars are sold as second hand. If this method had not been adopted, however, all work in this road district would have been suspended due to the inability to secure materials. The question of whether a contractor is justified in purchasing standard railroad equipment, is one which demands careful study. If such equipment can be operated long enough to take advantage of its low rate of depreciation, not ex- ceeding 10 per cent per year, privately owned standard railroad equipmait will probably prove economical. Even though the actual cost of hauling on some par- ticular job is increased due to privately owned railroad equipment, a contractor might be justified in purchasing such equipment because of the greater reliability of material supply. It is the cost of such intangible factors as uncertainty of material supply, which ruin contractors more often than the increased cost of some definite operation such as unloading or hauling material. Men who have had exper- ience in Europe claim that it is quite the common thing there for a contractor to own his own railroad equipment. Probably as road work is organized on a greater scale and large road building organizations are formed, the practice of owning standard railroad equipment will come into more general use. Particularly is this true of railroad contractors who enter the highway construction field, inasmuch as they generally possess standard gauge, large capacity, earth moving equipment which can be adapted to hauling material for highway construction. When road building material is stored in quantity at unloading points, the problem is to store the maximum amount of material on the minimum amount of space, which is frequently limited, and to rehandle the material most economically. The problem of rehandling material is a very important one, and is one to which many contractors do not give proper consideration. The rehandling of material is often very troublesome and expensive, and close attention should be paid to this problem. * * 73 The method, of storing material over a tunnel constructed of wood frames and sheeting has come into quite general use during the past two years, and is recognized as one of the best on account of the ease and economy with which mater- ials are rehandled. Traps are plaoed in the roof of the tunnel approximately 8 • feet apart, or every car length, thru which material can he charged into light railway cars. Due to the large amount of head room required, the tunnel system is impractical for loading any other type of haulage equipment than light railway. The tunnel system of storage provides the maximum amount of storage per unit of area occupied. A considerable proportion of the mterial piled over a tunnel will flow thru the trap by gravity, and continuous operation of the concrete mixing plant is thus assured in spite of temporary breakdowns of the unloading equipment. This is one of the biggest advantages of the tunnel system of storage. Continuous operation of the concrete mixing plant is also insured in spite of temporary delay in railroad shipments. PGR TAT. VIEW OF MATERIAL TUNREL SIDE VIEW OF MATERIAL TUNNEL 74. Material storage tunnels can tie classed under three general heads, namely, the tunnel entirely above ground, the tunnel entirely below ground, and the tunnel half below and half above. These three general methods are shown in the sketch below. 7/V Af 7-CS/V/V&A. 7~0 =7*/y' =/<$/-? T zi/* 0 30 -O " A material yard must sometimes be placed on a piece of rented ground where it is undesirable to excavate a trench for the tunnel, or the presence of rock or ground water may prevent sinking the tunnel. In such a case the tunnel must be placed above ground, as shown in case #1 above. Assuming a slope of 1 to 1 far the material, 25 per cent of the material will flow by gravity as shown by the dotted line. It is necessary to rehandle the remainder, and this must generally be done by means of a crane and a clam shell bucket. The problem of rehandling should be eliminated if possible, by adopting one of the other methods shown. Case #2 shows a tunnel entirely below ground. Assuming slopes of 1 to 1 for the material, 50 per cent will flow by gravity as shown by the dotted line. The remainder of the material can easily be rehandled by dragging it over the tunnel by means of teams and scrapers, or by means of a small gasolene engine and a power scraper. From the standpoint of rehandling, the tunnel entirely below ground is to be preferred. It is also obvious that a smaller amount of material must be rehandled when the tunnel is placed below ground, than with either of the other methods. It is possible, therefore, to operate for a greater length of time in case of a breakdown of the unloading equipment, than with either of the other methods. Many contractors prefer placing the tunnel entirely below ground even though the cost of so doing is considerably greater than that of the other two methods, and even though a pump must be installed far handling ground water. Case #3, with the tunnel partly below and partly above ground, is a method which is most generally used. In this method the material excavated from the trench is banked against the side of the tunnel, as shown by the cross-hatch- ing, so as to make the problem of refilling the trench an easy one. With a tunnel of this kind, 37 per cent of the material will flow by gravity. Due to the sloping earth banked the outside, the problem of rehandling material is practi- cally no more difficult than where the tunnel is placed entirely below ground. The quantity of material which can be stored by the tunnel method de- pends upon the length of the tunnel and upon the height to which material can be piled. The height to which material can be piled depends, in turn, upon the length of boom of the unloading crane or derrick. Data sheets showing the detail of design of tunnels and their storage capacity, will be found in the appendix. 75 The cost of a material storage tunnel depends, of course, upon the cost of lumber and the cost of labor* Tunnels have been constructed of old railroad ties and of timber cut down by the contractor in clearing the right of way* Such tunnels were very moderate in cost* As a rule, where dimensioned lumber is used at a cost of about $60.00 per thousand feet board measure and carpenter labor cost about $1.00 per hour, a tunnel build according to the design in the appendix, will cost about $10*00 per lineal foot in place. This is exclusive of the cost of grading, and is based upon a cost of about $25.00 to $30*00 per thousand feet board measure for fabricating. As shown by the design, the tunnel is so construct- ed that it can be knocked down and moved from one job to another. The use of structural steel frames in a tunnel has been proposed and has been given consider- able thought, but to date wood has been exclusively used in building tunnels ex- cept in one case where steel "I" beams supported the roof. Tunnel traps costing $23*50 each in March, 1921, must be placed in the roof of the tunnel every 8 feet* The final cost of the tunnel, therefore, is about $13.00 per foot. Where a large amount of material is to be stored during the inactive road building months, the tunnel system becomes very expensive. Due to the limit- ed reach of the boom on the unloading crane, it is necessary to place material in a long pile. A concrete road 18 feet wide, of a 1-2-3 mixture, and 7-1/3 inches average thickness, requires 1,120 cubic yards of sand and 1,680 cubic yards of stone per mile, or a total of 2,800 cubic yards of material* A crane with a 45 foot boom equipped with a 3/4 cubic yard clam shell bucket, can pile material to a height of about 20 feet. Assuming a 1 to 1 slope for the material, such a pile will contain about 15 cubic yards per lineal foot. A pile 187 feet long is, therefore, required to store sufficient material for 1 mile of road, while a pile 750 feet long is required to store material for 4 miles of road. Obviously a tunnel, at $13.00 per lineal foot, would be very expensive in this case* LONG MATERIAL STORAGE PILE In order to eliminate the expense of placing a tunnel thruout the en- tire length of a long pile of material, the use of short cross tunnels has been suggested. These tunnels would be placed crosswise of the material pile as shown in the following sketch. A small percentage of material would flow by gravity, and the remainder could be rehandled by means of a light drag line, or preferably by means of a hoisting engine and a line attached to a scraper. 76. -300 - o ' r 00X0 0SO-O R - r~> , — 7 TV A**/ > i 1 ‘ • *L l ; i 00/01X07' 3 TT y- £T sr > i*'/~r/f / -ro / R? - & S£’C7’/or an elevating 3cip, is used for unloading purposes, in addition to an operator for the gasolene engine. These men are needed to clean out cars, feed the elevator or bucket, and to shift cars. The methods of unloading material described in the preceding paragraphs, except the derrick or crane method, are not suitable for highway construction on a large scale, and are mentioned only as a matter of general interest. In determining the personnel required by various methods of road building, we will assume an 8 mile concrete road, 18 feet wide, with an unloading point at the center. Five methods of road building will be considered, namely, team or truck haulage with material dumped on the subgrade and charged into the mixer by hand, direct charging of the mixer by means of a 5 ton motor truck with compartment dump body, direct charging of the mixer by means of a Ford truck with special dump body, the combined light railway and motor truck system, and the complete railway system. The daily output will be taken at 400 lineal feet of 18 foot concrete road of a 1-2-3 mixture, averaging 7-l/3 inches in thickness. The quantities required are as follows: PER DAY Cement 285 bbls. or 54 tons Sand 85 cu.yds. or 128 tons Stone 128 cu.yds. or 355 tons TOTAL 30,160 bbls. or 5670 tons 8,962 cu.yds. or 13442 tons 13,442 cu.yds .or 18147 tons A light steam shovel such as the Erie or the Thew, equipped with a 30 or 35 foot boom, caterpillar traction, and 3/4 yard clam shell bucket, will form the unloading equipment. The tunnel system of storing material will be used with the complete railway plant, and the stock pile and bin method with the other plant s • The road we have under consideration will require 3,016 loads of ce- ment, 5,975 loads of sand, and 8,963 leads of stone. This is based on an average 92. load for a team of 10 "barrels of cement, l-l/2 cubic yards of sand, or l-l/2 cubic yards of stone. A fair rate of travel for a team hauling material over an ordinary dirt road is 220 feet per minute or 2-1 Jz miles per hour, while an allowance of 5 minutes for loading and 5 minutes for dumping is about right. For loading and unloading cement, however, an allowance of 10 minutes for each operation must be made when the load consists of 10 barrels and 2 men are assigned to this task. A daily travel of 20 to 24 miles is a good day’s work for a team. On the average haul of 2 miles on this road a team hauling sand or stone will make a round trip in 106 minutes, or 6 round trips per 10 hour day. A team hauling cement will average 5 round trips per 10 hour day. To haul 3,016 loads of cement at an average of 5 per day, will require 603 team days, while to haul 14,938 loads of sand and stone at an average of 6 per day will require 2,489 team days. The total number of team days required will be approximately the same whether a few teams are employed for a comparatively long period of time, or a larger number of teams for a shorter period of time. There is, however, more chance for delay due to bad weather, etc., when work is spread out over a long period of time than when it is completed as soon as possible. In the average case, the hauling must be accomplished in about the same period of time devoted to laying the concrete. In a preceding chapter it was pointed out that l-l/4 miles of 18 foot concrete road per month was a good rate of operation for a 14H3 paving mixer, with a good organization and an ample supply of materials. At this rate about 6-l/2 months will be required for actually placing the concrete on this job, without making any allowance for delay due to waiting on grading operations, cleaning up, etc. At a rate of 20 working days per month, 130 working days will be obtained in 6-l/2 months. Inasmuch as a total of 3,092 team days of work are necessary to haul material to this job, 24 teams must be assigied to this operation in order to complete it in 130 working days. If 5 ton motor trucks are used for hauling material and dumping it directly on the subgrade, a total of 1,134 loads of cement, 2,688 loads of sand, and 3,630 loads of stone must be hauled. Over ordinary dirt roads an average speed of 6 miles per hour loaded and 10 miles per hour empty can be maintained with a truck of this size. An allowance of 5 minutes for loading and 10 minutes for unloading and getting away, has been shown by experience to be about right when hauling sand and stone. For hauling cement the same rate of speed can be maintained, but an allowance of 20 minutes for loading and 20 minutes for unload- ing must be made. On the average haul of 2 miles, a truck hauling sand or stone should make a round trip in 47 minutes or 13 round trips per 10 hour day. A truck hauling cement should make a round trip in 70 minutes, or 8 per 10 hour day. To haul 1,134 loads of cement at the rate of 8 per day will require 142 truck days, while to haul 6,318 loads of sand and stone at the rate of 15 per day will require 486 truck days. To accomplish the 628 truck days of work in 130 days f will require the services of 5 - 5 ton trucks. Five ton trucks with dump bodies subdivided into compartments to permit 4 batches to be carried, are quite often used to dump directly into the mixer skip. At a speed of 6 mile 3 per hour loaded and 10 miles per hour enpty, with an 93 allowance of 5 minutes for loading and 12 minutes for dumping, a truck will per- form a round trip on the average haul of 2 miles in 49 minutes. This is at the rate of 12 round trips per 10 hour day, enabling a truck to deliver 48 batches to the mixer. Six trucks are, therefore, needed to deliver 300 batches to the mixer. The photograph below illustrates the method of charging a mixer direct by means of a 5 ton truck with a subdivided body* When Ford trucks are used to charge the mixer direct, an average speed of 12 miles per hour both loaded and empty is about right, with an allowance of 3 minutes for loading and 2 minutes for unloading at the mixer. At this rate a truck will make a round trip on the average haul of 2 miles, in 25 minutes, or 24 round trips per 10 hour day delivering 24 batches and traveling 96 miles* Inasmuch as the mixer requires 300 batches, at least 13 trucks must be kept in operation. To insure continuous operation, experience indicates that a stir plus of one-fourth to one-third trucks must be provided on account of the severe service to which these light units are subjected. FORD TRUCKS WITH 3FSCIAL DUMP BODY DIRECT CHARGING OF MIXER WITH 5 TON TRUCK 94 In operating a combined, light railway and motor truck plant, the mixer is started at the point nearest the material yard and is supplied entirely by railway -until the end of the l-l/2 miles of track is reached. At a rate of l-l/4 miles per month, the mixer will require 1.2 months or 36 days to reach the end of the track. State specifications permit hauling over the concrete after the expira- tion of 21 days, and inasmuch as the mixer is assumed to operate only 20 days per month, or two-thirds of the time, about three-fourths mile of concrete will be 21 days old by the time the mixer reaches the end of the track. This, then, is the minimum truck haul. The maximum truck haul will be 2-1/2 miles in this case, while the average truck haul will be 1-5/8 miles. Inasmuch as the trucks operate at all times over a finished road, they should average a speed of 10 miles per hour both loaded and empty. Experience indicates that an allowance of 5 minutes for loading 4 batch boxes and 10 minutes for transferring, is ample. At this rate a truck will make a round trip on the average haul of 1-5/8 miles in 34 minutes, or 18 per 10 hour day delivering 72 batches. An average of from 4 to 5 trucks will, therefore, be required on this job, when operating a combined light railway and motor truck system . In a comr bined light railway and motor truck system, the trucks are generally rented. On this particular job they will not be needed during the construction of the first l-l/2 miles of road on each side of the material yard, inasmuch as the railway will serve the mixer on this portion of the work. Trucks will be required during the construction of only about two-third3 of this road. In reality, therefore, the average number of trucks required thruout the life of this job, is only 3. DERRICK ON WAGON FOR TRANSFERRING BATCH BOXES On the railway portion of the combined light railway and motor truck haul, the average haul from the transfer point to the mixer will be 1 mile. As previously shown, 1-6 ton locomotive is generally sufficient. The railway operating personnel, therefore, will consist of 1 locomotive operator and 1 train man. A speed of 6 miles per hour and an allowance of 5 minutes for sv/itching trains at the mixer and 5 minutes at the material yard, is a proper basis on which to proportion the amount of rolling stock required for a complete railway plant. Assinning grades do not exceed 7 per cent, we can use a 6-car, 12-batch train, splitting it on all grades over 4 per cent. On the average haul of 2 miles, the round trip can be accomplished in 50 minutes or 12 per 10 hour day. Inasmuch as 95 each train carries 12 ‘batches, 1 locomotive will deliver 144 batches to the mixer per day. Two locomotives, by speeding up a trifle or occasionally using a little sand so as to permit hauling a 7 car train, can easily deliver 300 batches to the mixer. In proportioning light railway equipment it is customary, as pointed out before, to base the rolling stock upon a length of haul equal to three-fourths of the maximum. In this comparison, however, the haulage equipment will be based upon the average haul, inasmuch as this is the haul assumed for the other methods. In charging a mixer with a 4 bag batch of materials for 1-2-3 concrete by means of •wheelbarrows and shovelers, the following organization is generally required as a minimum: 3 - men wheeling sand 2 - men shoveling sand 4 - men wheeling stone 4 - men shoveling stone 3 - men handling cement 1 - man handling empty bags 17 - men In charging a mixer direct by means of trucks or by means of light railway haulage, 2 and 3 men respectively are required at the charging end of the mixer. Hie Ford truck method, however, requires 2 additional men at the turntable • When material is dumped on the subgrade or when hauling is performed over it, the subgrade must be trimmed by hand. In order to trim a sufficient amount of subgrade by hand to enable 400 feet of road to be laid per day, a subgrade gang of 10 to 12 men and a sub-foreman is required. Hie unobstructed subgrade charac- teristic of light railway haulage, permits machine trimming of the subgrade. Hie subgrader is generally pulled by means of a road roller, and sufficient subgrade for a day’s run can be trimmed in a few hours. In operating the subgrader, men engaged in curing the concrete or in maintaining the railway track are brought back to assist in the operation. Six men will trim all the subgrade required for a day’s run in 3 or 4 hours with a subgrader. This is equivalent to an average of about 2 men for 10 hours* The subgrader is sometimes pulled with a tractor* <5 96 When the mixer is aharged direct by means of a 6 ton or Ford truck method, the combined light railway and motor truck method, or the complete railway method, btilk cement can readily be used. The method of unloading bulk cement and handling it at the material yard, has been outlined in the previous chapter. An average of about 2 men is generally sufficient to unload bulk cement at a rate which will permit building 400 feet of 18 foot concrete road in 10 hours. When bagged cement is used, an average of about 4 men is required. It will be assumed that a finishing machine is used on all these methods so that the personnel required for setting forms and for finishing will be the same for all. The personnel required for a job of the kind we have assumed, under average conditions, is about as follows: SYSTEM HAND CHARGING DIRECT CHARGING Team 5 Ton Truck Ford Truck 5 Ton Truck Comb. Rwy. and Truck Complete Railway Material Yard Crane Operator 1 1 1 1 1 1 Crane Fireman 1 1 1 1 1 1 Bucket Man 1 1 1 1 1 1 Car clean-up men 2 2 2 2 2 2 Unloading bagged cement 4 5 * * * * Unloading bulk cement * * 2 2 2 2 Bin Gate Men 2 1 2 1 1 ♦ Tunnel Men * * ♦ * * 2 Water Boy 1 1 1 1 1 1 Hauling Material Team Drivers 24 * * * * * Stable Men 4 * * * * * Truck Drivers * 5 13 6 3 * Garage Men * 2 2 2 * * Locomotive Operators * * * * 1 2 Train Men * * * * 1 2 Man to fill radiators * * 1 * * * Turntable Men * * 2 * ♦ * Transfer Point Men * * * * 3 * Track Men * * * * 2 3 Material Yard and Hauling Foremen 1 1 1 1 1 1 Mixing and Placing Concrete Mixer Operator 1 1 1 1 1 1 Mixer Fireman 1 1 1 1 1 1 Finishing Mach. Operator 1 1 1 1 1 1 Concrete Spreaders 3 3 3 3 3 3 Charging mixer 17 17 2 2 3 3 Setting Forms 3 3 . 3 3 3 3 97. HAM) CHARGING DIRECT CHARGING- Team 5 Ton Ford 5 Ton Comb. Rwy. Complete Truck Truck Truck and Truck Railway Mixing and Placing Concrete Trimming Subgrade 12 12 12 12 2 2 Sub-foreman on subgrade 1 1 1 1 * * Roller Operator 1 1 1 1 1 1 Curing Concrete 4 4 4 4 4 4 Pump Man 1 1 1 1 1 1 Pipe Man 1 1 1 1 1 1 Water Boy 1 1 1 1 1 1 Watchman 1 1 1 1 1 1 Foreman 1 1 JL. 1 1 JL 89 67 62 50 42 41 In addition to the operating personnel listed above, a superintendent is generally in charge of the entire job. A time -keeper, a material cleric, a general office man for the field office, and a cost keeper are provided on the average fair sized job. A garage for field repairs with 1 mechanic and helper, must be provided in order to keep the motor trucks in shape. Particularly is this true with the Ford trucks, for they travel an average of 96 miles per day. The average travel of the 5 ton trucks is 56 miles. No garage men are provided for the combined light rail- way and motor truck plant, inasmuch as the motor trucks are generally rented and the owner provides for their repair in his rental charge. A blacksmith and a helper are generally necessary on a job of this size. Each contractor has his own arrangement for paying his men, but all of them generally have a certain number " straight-time” men. These men are paid the regular wage on rainy days as well as working days. Most contractors carry a few men thruout the year as a nucleous for their organization, generally the foremen and sub-foremen, the mechanics, the crane operator, and the mixer operator. The foremen and the superintendent are paid either by the month or by the year, while the rest of the personnel, except the ”strai git -time” men, are paid only for the actual time they work. Frequently the office force, or at least a part of it, are carried thruout the year. Most progressive contractors employ an engineer for the purpose of checking the quantities shorn on the plans, and for doing such other engineering work as is necessary. . - 98 CHAPTER XII. COST OF OPERATION. One of the most common mistakes in highway construction, in judging the merits of a plan of operation, is to give undue consideration to the cost of hauling, regardless of the fact that hauling is hut one of a number of coordinated functions which must he performed, though it is no doubt one of the most important. If hauling were the only operation to be performed in road building, then the cost per ton mile would be the proper criterion upon ■which to base judgment. In order to correctly judge of the merits of any system of road building, all of the oper- ations involved must be considered as a whole. It is manifestly false economy to adopt a plan of operation because the cost of hauling is lower than by some other plan, but where the losses due to extra labor involved in charging the mixer and trimming the subgrade, loss of material due to dumping on the subgrade, loss due to extra concrete because of inaccurate subgrade, etc. will more than absorb any saving in the cost of hauling. The actual cost of hauling per ton mile by the combined light railway and motor truck system on a small job, 3 or 4 miles long, is frequently greater than it would be if teams or trucks were hired by the day. The economy effected in charging the mixer, trimming the subgrade, reduction of delay due to wet weather, etc., by the comb ined light railway and motor truck system, however, will more than compensate for the increased cost of hauling. In spite of all this, however, undue emphasis is frequently placed on tie cost of hauling per ton mile. Another common and costly mistake frequently made, is to assume a uniforn cost per ton mile for hauling regardless of the length of haul. The cost of haul- ing per ton mile varies inversely with the length of haul. When a comparatively expensive plant, such aslight railway or motor truck, is used on a short haul, the actual cost of hauling per ton mile is frequently greater than by team. As the haul increases, however, the railway and truck cost finally becomes less than that by team. A cost per ton mile for hauling is absolutely no good, unless the length of haul and percentage of waiting time involved is also given. The cost of hauling, like any other cost, varies with local conditions, with the length of working season and weather conditions, and with the managing ability of the contractor. It is obvious that the unit cost of hauling in hilly country or on roads of a certain character, will differ considerably from the cost in level country or on roads of another character. In a part of the country where the working season is longer than it is in another part, the unit cost of hauling will be less. Plant and overhead charges must be provided for during the working season, no matter how short it may be. A greater amount of work can be performed in a long season than in a short one, and in a long season fixed charges can be spread over greater mileage than in a short season. The unit cost of hauling in a wet climate, is generally greater than in a dry climate. On certain jobs it might be necessary, for business reasons, to charge off a greater percentage for depreciation than on other jobs, and in such a case the unit cost of hauling will be increased. Equipment purchased during a period of unusually high prices, should be charged off at a greater rate than equipment purchased during a normal or a rising market. All of these factors influence unit costs very materially, and on this account a contractor should use great caution with figures from some other job or part of the country where conditions are not fully known to him. Data issued by manufacturers of equipment frequently oraitSy, many vital factors which go to make up a cost, and this data should be used by contractors only after 99, careful scrutiny. In the final analysis cost is merely a relative term, and is not by any means absolute or fixed. The cost to one man of performing a certain work, might be entirely different from the cost to some one else, on account of certain peculiarities of temperament or conditions. It is again desired to emphasize, therefore, that any cost obtained under conditions not absolutely known, should be used only as a guide and with caution. The term cost is a composite one, including a large number of elements. All too frequently the inexperienced man fails to place proper emphasis on some of the more or less intangible elements, because his vision is obscured by the con- crete elements of labor and materials. While it is true that the cost of labor and materials generally forms the greater part of the final cost, it is equally true that failure properly to consider other elements will result in a loss even though the cost of labor and material has been properly estimated. Or if the other elements which make up a cost in addition to labor and material have been kept in mind, the mistake is frequently made of providing for them insufficiently. Perhaps the element of plant charges is more frequently under-estimated than any of the other so-called intangible elements. The danger of this practice is due to the fact that it is generally not discovered for a number of years, vi th the result that the apparent profit earned during the previous years is very con- siderably reduced or is really not a profit at all. Failure properly to estimate other elements of a cost generally becomes apparent at least by the completion of the job, but failure to make proper plant charges is not apparent at once and is, therefore, much more dangerous. Plant charges consist of depreciation on the equipment, interest on the investment, field repairs, shop repairs, storage charges, insurance, and obsoles- cence. These charges are generally expressed in terms of a percentage of the initial cost of the equipment. The proper percentage to be charged depends upon the type of equipment and whether it is special or standard, upon the job and the conditions under which it is employed, and upon its second hand value and scrap value. A piece of special equipment purchased for a particular job, which will probably be of but little further use, should obviously be charged entirely to this one job. The type of equipment will affect the plant charge very materially, for it is apparent that a steam shovel or a heavy earth moving car will last longer than a concrete mixer or a finishing machine. If equipment is operated on a double shift, the rate of depreciation and the amount of repairs will naturally be greater than if it is operated on a single shift. A steam shovel or cars working in rock, will naturally wear out faster than if working in earth. Some equipment will have a considerable scrap value, while other equipment will have practically none. Some equipment will have a higher second hand value and a broader second hand market, than other equipment. Some equipment might have been purchased during a period of high prices, while other equipment might have been purchased during a period of normal or low prices. All of these factors must be considered and proper weight given to them, in deciding upon plant charges. The estimated rate of depreciation is not always based upon the probable life of the equipment, but frequently upon the time in which the business judgment of the contractor indicates that he must recover his investment. For instance. most concrete mixers will last for 6 or 7 years, but it is common practice to base the rate of depreciation in computing plant charges upon a life of 4 years. « ' ♦ 100 . More mistakes are made in estimating plant charges than in any other element of cost, and a considerable amount of experience is required for an intelli gent estimate. A copy of a "Guide for Estimating Construction Plant Charges" re- cently issued by the Associated General Contractors of America, will be found in the appendix. This Guide represents the consensus of opinion of a considerable number of contractors as to what proper plant charges should be. One thing which must always be kept in mind, is that plant charges must be earned during the construction season^no matter how short it may be. For instance, a contractor migdit purchase motor trucks to be used in road building during, say, 6 months of the year. He might charge only half of the yearly plant charges to the road work, assuming that the other half will be earned during the winter time in performing other work such as hauling coal. Unless he has absolute assurance that he will be able to obtain work for his trucks outside of his road work, such a procedure is very risky. Even though he has proper assurance that he can haul coal during the winter time, it is not good business for him to depend upon an auxiliary operation to carry part of the plant charges on equipment pur- chased primarily for road work. If equipment is purchased primarily for accom- plishing some purpose, all of the plant charges should be charged to it. If this can not be done without making the cost excessive, then obviously the equipment is not the proper kind for the purpose in mind. A contractor is frequently confronted with the problem of deciding just what proportion of the yearly plant charges is to be assigned to some one job. This job might be secured early in the yaar, and might not be of quite sufficient size to keep him busy during the entire season. He must then decide whether to assign all the plant charges for the year to this one job, or whether to assign only a portion in the expectation of securing another contract which will absorb the remainder. The decision in this matter must be based upon local conditions, and upon the experience and judgment of the individual. If all the yearly plant charges are assigned to the first job, the cost might be so high as to preclude securing the contract, while if only a part is charged to the first job, the risk is incurred of not securing another job to carry the remainder. In addition to the plant charges, there are a number of other important charges ■which go to make up a cost. Some of these charges are directly applicable to each job, while others are general charges which must be pro-rated among the various jobs. The cost of erecting bins and tunnels and dismantling them, loading and unloading equipment, freight on equipment to and from the job, the cost of erecting and operating the field office, certain traveling expenses, etc., are generally directly chargeable to each job. If bins and tunnels are so constructed that they can be dismantled and moved from one job to another, it would be proper to assign a certain proportion for depreciation, etc., to each job. When equipment is shipped to a job, it is seldom known -whether it will be re shipped from that job to another one or back to the contractor's yard. It is generally wise, therefore, to charge freight both ways from the contractor’s yard to the job. When a camp is operated b^ the contract system, the cost to the con- tractor is generally fixed. A well operated, sanitary camp, is the best precau- tion a contractor can take to insure an adequate supply of efficient and contented labor. Rather than run the risk of a poor camp by contracting for its operation, it is generally better for a contractor to operate the canp himself. Even though a sufficient charge cannot be made for board and room to make the camp self-sus- taining, it is always a good investment to maintain a good camp and charge the loss to "overhead". 101 The term "overhead" represents the least tangible of the many elements which comprise a cost* "Overhead" can really he divided into two general classes, namely, "job overhead" and "general overhead"* "Job overhead" includes super- intendents, field office expense, traveling expense, watchmen, timekeepers , cost keeper, clerks, telephones, stationery, lights, and all other costs on a job not directly assignable to some other element. "General Overhead" includes the executive and administrative expenses of operating the general office, cost of securing work, attending conventions, salaries of employees during winter months, feed of stock during winter months, and all the expenses not directly attributable to some particular job. "General overhead" is pro-rated among the various jobs in accordance with the experience and judgment of the contractor, and naturally varies with particular conditions and organization. The larger the organization the larger the "overhead" as this is one of the penalties of size* Each contractor generally has his own cost system, which he considers to be more or less adapted to his own peculiar conditions and problems. This of course is frequently so, and no attempt will be made in this thesis to enter into a detailed discussion of various cost keeping systems. The Wisconsin Highway Department has recently prepared a schedule for highway contractors containing the many elements of cost involved in road building, a copy of which will be found in the appendix. Bulle tin #660, of the United States Department of Agriculture, entitled "Highway Cost Keeping" , treats of cost keeping forms and methods. This bulletin can be secured from the Superintendent of Documents of the Government Printing Office, in Washington, D. C. While it is not desired to enter into a detailed discussion of methods of cost keeping, still it is believed to be desirable to point out some of the essential features which a good system should include. The cost of fuel and oil should be kept separate, as well as the cost of coirmon labor and the cost of skilled labor. The cost of foremanship should be kept separate from the cost of labor, because the proportionate cost due to foremanship varies with each job* The "job overhead" should be kept separate from the "general overhead" and the cost of securing business, such as looking over work, making out bids, advertising, etc* 7 should be kept by itself. The cost of superintendents, time keepers, clerks, watchmen, books and stationery, field office expense, etc* ? should all be kept separate. Above all, full and complete data concerning the conditions surrounding a job should be recorded. Photographs will help materially in bringing to mind conditions years after the work has been completed, and should be liberally used. Cost data is/all too often rendered valueless by failure properly and sufficiently to describe the prevailing conditions when it was obtained, and much of it is not properly subdivided or analyzed so as to permit it to be applied to other work of like or similar character. Too much emphasis cannot be placed upon the absolute necessity of providing full and complete data to accompany information on cost, if this information is to be of much value after the figures are "cold"* A oommon practice in estimating cost is to estimate first the unit cost, and then to obtain the total cost by multiplying the unit cost by the number of units. In certain work, such as earth work, this is the method that must general^ be used, but in hauling, mixing concrete, or unloading material, a better method is to estimate the total cost and then obtain the unit cost from the total if desired. For instance, in estimating the cost of placing concrete, contractors frequently figure the daily cost per square yard* Certain additions must then be made to provide for delays due to rain, loss due to inaccurate subgrade, etc* and inasmuch as the units involved are small, an error of a few cents will represent a considerable percentage of the cost. A better method is to estimate the total time and total cost required to complete the work, making such allowance for delay due 102 1 to wet weather, starting and stopping the job, moving the material yard, lack of material, etc. as experience and judgment dictates. Proper allowance can readily he made for loss of material, straight time men, etc# If the method of estimating hy totals is followed, there is less chance of improperly providing for contin- gencies than in the method of estimating hy units# Sometimes several unloading points are available, and the question arises as to how much of the road lying between two of them is to he constructed with material hauled from each. The problem is further complicated hy the fact that the cost of establishing one material yard is frequently greater than the cost of establishing another, and the cost of material at one point is greater than it is at another. The general rule of dividing the road so as to equalize the maximum haul from each material yard, must, therefore, be changed to dividing the road so that the unit cost of material from either yard at the dividing point is the same. This rule must sometimes be modified considerably in order to adapt the equipment on hand to the job, to eliminate grades opposed to the leaded train, etc. It is generally worth while, however, to determine the points of equal cost on a road and to adhere to them as closely as is practical, for material is fre- quently hauled from one yard when it could be more economically hauled from another The problem of determining the point of equal cost is not involved in that of determining the number of unloading points to use, for a decision in this respect should have already been reached. In determining the point of equal cost, it is obvious that the increased cost of establishing one naterial yard over that of establishing another must be absorbed by the tonnage of material hauled from that yard. In order to illustrate the method of dividing a road when material is hauled from two unloading points, we will consider a road such as that shown in the sketch below. Material was available on railroad sidings at points "A” and "C", and the cost of hauling from either unloading point to the road "BD" was estimated at $0.40 per ton mile. A mixer was started at point "B H and the problem was to determine how much road to build with material hauled from "A” and how much with material hauled from ”C". A siding was already in place at "C”, but an expenditure of $3, 000 was necessary to provide a siding at "A". The combined light railway and motor truck system of haulage was used. The material required was as follows: Cement 3,760 bbls. or 718 tons per mile; 5,026 tons per 7 miles Sand 1,120 cu#yds#or 1,680 tons per mile; 11,760 tons per 7 miles Stone 1,680 cu.yds.or 2,270 tons per mile: 15.890 t ons per 7 miles 4,668 tons 32,676 tons The cost of material wa3 approximately as follows, the cement price per ton being derived from a price of $2#50 per barrel and a weight of 376 pounds. 103. Cement per ton Sand per ton Stone per ton POINT "A" $13.30 0.60 2.00 POINT 11 0" $13.30 1.25 2.00 The proportions of 1-2-3 by volume are equivalent to 1.00-2.36-3.19 by weight, based upon a weight of 276 pounds per barrel of cement, 3,000 pounds per cubic yard of sand, and 2 # 700 pounds per cubic yard of stone. The weighted mean cost of material at each point is, therefore, as follows: POINT "A" $13.30 0.60 2.00 1.00 x 2.36 x S.tl.9 x 6.55 $13.30 1.42 6.38 $21.10 POINT »C» 1.00 x $13.30 2.36 x 1.25 3.19 x 2.00 6.55 = $13.30 = 2.95 = 6.38 $ 42*65 $21.10 I 6.55 $3.22, the weighted mean cost per ton at "A" $22.65 6.55 $3.45, the weighted mean cost per ton at "C" Let X represent the mileage of road to be constructed with material hauled from "A", and Y the mileage to be constructed from "C". The tonnage of material hauled from "A", therefore, equals 4,668 X. The weighted mean cost of material per ton at "A" is $3.22, while the cost at "B M , after hauling 1 mile, is $3.62. The weighted mean cost of material at ”0" is $3.45, while the weighted mean cost at "D”, after hauling 3 miles, is $4.65. The cost of material hauled from "A M at any point along the road distant X from "B" , will be $3.62 plus 4^668°X plus $ 0#4 ° x ec iuals $3.62 plus plus $0.40 X. The cost of material hauled from '’C", at any point Y from "D M , is $4.65 plus $0.40 X. Equating these expressions gives a value of 4.62 miles for X. In other words, under the condi- tions assumed, material hauled 4.62 miles from point "B", is equal in cost to material hauled 2.38 miles from point "D". This, therefore, indicates the mileage of road to be built with material from each unloading point, in the absence of other modifying conditions. If a complete railway system were employed, a division of the road such as that indicated above would involve more equipment than if the maximum haul from each point was equalized. In such a case it rai^it be more economical to divide the road so as to reduce the amount of equipment required, rather than to divide it strictly in accordance with the point of equal cost. The accompanying graph illustrates a graphical method of determining the point of equal cost. The advantage of the graphical method is that it readily in- dicates the extra cost involved, -when material is hauled beyond the point of equal cost. For instance, in the example shown above, suppose that it is desired to determine the increased cost due to building 3^- miles of road from H C” rather than the 2.38 miles indicated by the curve. By continuing the curve representing the cost of mterial hauled from point "O” to the 3-1 Jz mile point, we see that the unit cost would be $6.10 per ton rather than the $5.20 when hauled from ’'A". The area of the triangle shown by the cross-hatching gives the total increase in cost, when the altitude is taken in terms of tons of material. In this particular case the increased cost would be $6.10 minus $5.20 times (4,668 x 1.12) times 1 Jz equals $2,362.00. A study of this character will enable the contractor to as- certain whether the increased cost is justified by the plan he has in mind. I IS8SSBS88S88! 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Place the partition wall to give proper ratio between sand and stone for various mixes. Place 1-inch tie rods in each system ol 6" x 6 " waling pieces 6' 0" apart horizontally. Waling pieces are bolted to 6" x 6 " verti- cals and to each other with six x 13 1 -j" bolts at each joint. Place Lake- wood tunnel traps at proper intervals at bottom. Lise lew nails in the floor- ing. Hold vertical sheeting in place by means of 2" x 4" on inside bolted through to 6" x 6" wales on outside. The Lakewood Engineering Company Cleveland, U. S. A. Bill of Material Description Dimension Req’d. B. F’t Caps and Mudsills 12"xl2"x8'-0" 32 3072 Posts 1 2 " x 1 2"x7'-0" 32 2688 Stringers 2"xl 2"xl4'-0" 40 1 1 20 Side Wales 6"x6"xl4'-0" 30 1 260 End Wales 6"x6"x9'-0" 6 162 Partition Wales 6"x6"x8'-0" 3 72 Flooring 2"xl 2"x8'-0" 60 960 Sheeting 2 "x 1 2 "x 1 2'-0 " 135 3240 Verticals 6"x6"xl3'-2" 12 500 Sheeting Holder 2"x4"xl 1 '-6" 24 192 Brace 2"xl2"x3'-6" 32 224 Bolts 5 8 "- x 13 X" 216 310 lb. Bolts ( For Sheet H.) y 2 "-xioy 2 " 72 Tie Rods 1 "x9'-6" 27 702 lb. Nails 201) 50 lb. Nails 10D 25 lb. ■J 19-1 a ^ is VS * % "J <0 j*- g t 8 | * * vs "1 ♦ "n. M * ■*4. «0 «0 •VK}- «0 1!) Uj * n- Niq *5 asp <*) it > T S) V 't- Si V* > 1 a O' N *> 1 J s * § a <0 THE LHKEWOOD ENGINEERING CIO. CZL. EVEL. RND O. 4- 27 - ZO SUBJECT: D/MCN <5/0 A/ >5 SKETCH SHOW//VG V&RIOUS BRTCHCS ORTFl SHEET No 7 8 t "1 ''‘iT > >1 MM ft) kwQ 3 * OJ ^-x >» S "i M «**}- p> X ") 1 "X • <0 ft 1 >x 1 ft 1 .k 5 3 (T M l 1 ' P) * ; -M- P) irj : M mm J «o ^x ft: M "n M N ">•* «>h{- w S 9T} •0 M M M * * CV) r «M "x •*x <0 *0 ft x ft ft ft 5: ft: ft: ft: ft) so m "i *• ft A*d A. a ft O' N 5 3 M M ft t V -J ~ •ft i 'X • * >5 5 ■0 l MM ft i M i X i ft ft ft) 1 •0 l k ft. jc 3 Vj ft O' m h- ft 5: Mx}. ft •ihj. j ftj N MM IT) <\J 5C > > V ’*'x MM MM s •J M W ft ft ft ft II ft 1 ft ■>x >x l *x X ft) ft) ft) i 55 ft ft ft: ft: ft £ >x u_ i? 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This wedge is heavy enough to allow driving with a sledge hammer. It has a quarter-inch bear- ,ng . ( ; 1 , 1 lhe stak *. and cannot become bent or . rap,rll y w,,ni - T |le se wedges may, however, . e f s,ly re I )Iace( l when worn, They are held ' pockets and cannot become lost on Made extra heavy to stand hard service Reinforces head of rail at joint 6 Lakewood-Hotchkiss Steel Forms for Curbs, Gutters and Sidewalks The Lakewood-Hotch- kiss method combines the use of a better form and a better method, resulting in more nearly perfect con- crete work. The design of the forms is such that the same side rails can be used for curb, gutters, sidewalks, foundations, culverts, etc. Thus, with a compara- tively small investment in Lakewood-Hotchkiss Steel Forms, a contractor can use this equipment for practically any kind of work on which he cares to bid. One of the attractive features of Lakewood- Hotchkiss Steel Forms is the simple locking device which makes the entire form a strong substantial use of bolts, stakes or The same side rails are used for all kinds construction unit without the braces. This is accomplished by locking the division plates to the side rails with a wedge key, as illustrated. That the use of the Lakewood-Hotchkiss sys- tem insures a more nearly perfect concrete and gives an absolutely perfect ex- pansion joint can be readily appreciated from the fol- lowing discussion. In the first place this system allows the removal of the side rails and dividing plates 20 minutes after the concrete has been poured. To employ the Lake- wood-Hotchkiss system successfully a fairly dry mixture must be used. As it has been generally agreed that a dry mix makes stronger con- crete than a wet one, this is an advantage. Using a dry mixture results in a dense concrete of maximum strength. The forms may be removed 20 minutes after pouring 7 A perfect expansion joint is assured when the Lakewood- Hotchkiss method is used. The dividing plates are removed last It is also generally agreed that a good, dry mix, when allow- ed at least 20 minutes to take initial set, is stiff enough to stand without support. If this is true, no harm can result from removing the side forms 20 or 30 min- utes after pouring. Furthermore, as the concrete will stand up when the side rails are removed, it is ab- solutely certain that the concrete surfaces will not come together when the dividing plate is withdrawn. Thus an absolutely perfect ex- pansion joint is bound to result. Templates for Lakewood-Hotchkiss forms can be furnished quickly to meet any specifications for curb, gutter and sidewalk construction Being able to remove the forms quickly, thus getting maximum ser- vice from his equipment, This curb form is typical of Lakewood-Hotchkiss steel forms in that the form is a strong, substantial unit, using no bolts, stakes or braces 8 Lakewood-Hotchkiss sidewalk forms are held rigidly in place by locking the dividing plates into the side rails. Each square is uniform and the alignment perfect a contractor using the Lakewood-Hotchkiss method reduces his investment in forms to the minimum. Another big advantage to the contractor of Lakewood-Hotchkiss Forms is the ability to use the same side rails for various kinds of work. To illustrate, let us suppose that a contractor has a supply of 5-in. side rails, 10 ft. long which he purchased for sidewalk con- struction. After completing the walk he secures a straight curb job, which we will suppose to be 20 in. deep, 8 in. on the base, and 5 in. on top. To complete his outfit, the contractor simply orders a few curb templates to correspond to the cross-section of the curb. The 5-in. side rails are built up 20 in. high and securely locked into a strong substantial form by the Lakewood-Hotchkiss locking system. The next job, we ll say, is a combined curb and gutter, a cross-section of which may call for a template 15 in. on the back of the curb and 10 in. on the face of the gutter. Using the Lakewood-Hotchkiss method, the con- tractor orders a few curb and gutter templates and his outfit is again complete. Three of the 5-in. side rails make up the back of the form and two 5-in. rails give a 10-in. gutter face. (Left) — Lakewood-Hotchkiss forms, using 6-in. radius corners, to make approach from street to residence. (Right)- — Spring steel flexible sections simplify complicated curved work and eliminate tedious sawing and fitting 9 I.akewood-Hotchkiss dividing plates or templates can be furnished quickly to meet any specifications. Several typical ones are illustrated 10 I.akewood-Hotchkiss forms lend themselves to all kinds of curb, gutter and crosswalk construction From this it is readily seen that, being able to use the same side rails for various kinds of work, the contractor using Lakewood-Hotch- kiss system has a minimum amount of money tied up as an investment in forms. In addi- tion, he has the advantage of all the well known economies of using steel forms. Lakewood-Hotchkiss side rails are carried in stock in 4, 5, 6 and 12-in. sizes. Dividing plates to meet any specifications can be shipped by express three days after receipt of order. A special high-carbon blue annealed steel is used in all Lakewood-Hotchkiss forms, giving a lighter form just as strong as a heavier form of softer steel. And because plates for Lakewood-Hotchkiss forms are rolled to exact size, there are no sharp, sheared edges — the forms can be handled without danger of the men cutting their fingers. All side rails are slotted every twelve inches and are fitted with end connections. With this frequent slotting most any condition can be met by inserting dividing plates or stop plates at any desired point. Several typical dividing plates are illus- trated. When ordering dividing plates, or templates, as they are sometimes called, kindly note the illustrations carefully to see that your description is as complete as those shown. Curved walks and intersections easily built the Lakewood-Hotchkiss way 1 1 Lakewood-Hotchkiss Steel Forms for Foundations, Walls and Culverts The Lakewood- Hotchkiss method of wall construction closely lollows the regular method of wooden form con- struction, but elimi- nates all waste of material and labor, the need for upright supports, and fitting and sawing. In wall construc- tion the standard 10- ft. channel sections, 6 or 12 in. wide, are commonly used. Other widths may be used. To hold these side rails accurately to the width of the wall, narrow, locking tie plates are inserted in the vertical slots in the side rails. The flanges of the side rails are punched for inserting the pins where necessary. This, however, is not usually necessary ex- cept when three or four sections are placed one above the other before filling. The sections may be assembled and then lifted to position or may be assembled right in place. The slip tongue and sock- et connections permit removal of any of the rail sections without interference. The locking tie plates are made as nar- row as practical and slightly tapered with shoulders, so that when keyed through the The same Lakewood-Hotchkiss side rails as used for curbs, gutters, or sidewalks are used y] in wall construction A fine job — and all the waste in lumber and labor saved by using Lakewood-Hotchkiss Steel Forms Perfect angles made easily and economically the Lakewood-Hotchkiss way tongues of the tie plates the channels are drawn firmly against the shoulders of the tie plates. Thus the whole form is held securely together and in alignment. The taper allows the tie plate to be easily with- drawn -from the concrete. placed holds the forms in more perfect posi- tion and alignment, without bolting, bracing, or otherwise sustaining them. The corner sections are uniform and are made the same width as the channel rails. These are so constructed that the two ends of Each section of Lakewood-Hotchkiss forms is a unit in itself. The units can be lifted to position or assembled right in place Locking these forms with narrow tie plates and pulling them horizontally through the wall is new and original. It surprises the builder to see how efficient and practical it is. By this principle every shovel full of concrete the angles are brought up square and fit nicely into the intermediate sections. They are held by slip tongue connections, the same as the regular wall channel rails. These cor- ner sections are also locked with the same The Lakewood-Hotchkiss principle is the same for wall construction as for curb and gutter work. The same side rails and method of locking are used throughout 13 narrow locking tie plates and can also be assembled and then raised in position on the wall. To more minutely describe the corner sec- tions, the outside channel rails are intended to take up 3 ft. of space on the building line, and the inside channels 2 ft. on the inside line, on a wall 1 ft. wide. One of the outside rails is 3 ft. 6 in. long; the other outside rail 3 ft. 0 in. long. The 3 -ft. rail has tongues on one end w'hich connect in the vertical slots of the other outside rail at the 3-ft. point. This makes a perfect right angle. These rails are so slotted, however, as to easily provide for an adjustment in the width of the wall when desired, without changing the entire corner section. To more fully describe the working opera- tion of these wall forms, and to show the prac- tical efficiency in actual use, suppose the first section is set in place. It can be either 6 in. or 12 in. in depth. As fast as the form is filled the next section is raised in position, resting on the flanges of the section just filled. It is the same Lakewood-Hotchkiss prin- ciple of placing, filling, removing and replac- ing — a rapid, continuous operation, making steel forms in every construction an eco- nomical proposition. To work to best advantage for rapid con- struction you should have intermediate sec- tions of different lengths, so that the forms may be erected around the entire building, unless the building is larger than your equip- and remove the lower channels, at thesame time pulling the narrow locking plates through the wall. The channel sections thus removed are ready for replacement on top of the last section filled. This process is continued until the desired height is reached. ment would care for. In this case the erection may be carried to any point in the building line and a stop-plate locked in the form. To illustrate, if the building is 36 ft. x 26 ft. no intermediate short sections would be needed as the corner sections would take up 6 ft. of 14 the building line. Hence you would require three regular 10-ft. sections on each side and two regular sections on each end. If the building is 42 ft. on one side you would need three regular sections and one 6-ft. section to fill out this space on accurate measurements. The space may be varied also by slipping in flat plates where the building line makes a difference in inches. A little careful study in this connection will show how nicely this method can be worked out. These wall forms can be used to good ad- vantage where the work will permit of con- veying the concrete by means of chutes, or when portable scaffolding arrangements are u sed . For culvert construction the same side rails are used as in curb, gutter, sidewalk and wall work, in connection with the Lakewood- Hotchkiss collapsible support. The same Lakewood-Hotchkiss method of locking the forms is also employed, the narrow locking tie plates being pulled horizontally through the wall instead of vertically so that concrete of any consistency may be used. Header wall connections are so constructed that they will connect perfectly with the throat walls and, at the same time, give header walls and parapets parallel to the street. The collapsi- ble support, and other details, are shown in the line drawings. Post forms, also, are included in the Lake- wood-Hotchkiss line of steel forms. These post forms are adjustable in lengths. Forms are removed without disturbing the posts until the concrete has set. Made in batteries so that 5 or 10 posts can be poured at one time. The same form is used to make plain or ornamental posts. The posts can also be cored in the forming to permit bolting on of steel or wooden pieces such as guard rails etc. The division plates are held securely in place by connecting with the end plates. The whole form is rigidly locked by wedge-shaped steel keys. I'he Lakewood Engineering Company, Cleveland, U. S. A. Branch Offices Atlanta 90]/i N. Forsyth St Baltimore American Bldg Buffalo 256 Main St Chicago Lumber Exchange Bldg Cleveland Racine Bldg Dallas Sumpter Bldg Des Moines Hubbell Bldg Detroit David Whitney Bldg Kansas City Ry. Exchange Bldg Memphis Central Bank Bldg. Milwaukee Milwaukee Athletic Club Bldg. Minneapolis 529 Second Ave. South New York 141 Centre St. Philadelphia Widencr Bldg. Pittsburgh Union Arcade Richmond Times Dispatch Bldg. San Francisco Rialto Bldg. Smith Booth Usher Co. .. Smith-Booth Lusher C’o. . Clyde Equipment Co. .... Clyde Equipment Co R. B. Everett & Co Waldo Bros. & Bond Co. Representati ues 50 Fremont St., San Francisco 228 Central Ave., Los Angeles 16th and Lpshire Ave., Portland 542 First Ave. South, Seattle 3118 Harrisburg Blvd., Houston, Tex. 181 Congress St., Boston, Mass. Patent Notice The devices described in this publication are protected by patents and patent applications pending. 77788-5M-2-21 1 5 Bulletin No. 29-D Page 2 Lakewood Service to Road Contractors Because no two road construction jobs are exactly alike, it is not possible to say what the size or cost will be of the paving plant needed for the work without a thorough study of the conditions to be met. Lakewood engineers, specialists in paving plant layout and operation, are at the service of the contractor who contemplates undertak- ing a large job. Upon request they will gladly assist and advise with him in planning his work and, after a personal investigation, will make an estimate as to the equipment needed, and what the approximate cost of the work will be if handled by the Lakewood method. This service is given without charge and involves no obligation on the part of the con- tractor. /'he Lakewood Engineering Co. Index to Bulletin No.29-D Lakewood Service to Road Contractors. . 2 About the Lakewood Engineering Co. . . 4 How Lakewood Applies Modern Manu- facturing Methods to Road Construc- tion 5, 6 Unloading Plant 7, 8, 10 and 1 1 Hauling to Mixer 8, 9 and 12 Plant Layouts 10 and 1 1 Operations at Mixer 12, 13 and 16 Tamping and Finishing Concrete, 16, 17 and 1 8 Mixing at Central Plant 18 Road Car 20 Batch Box Cars and Batch Boxes 21 Finishing Machine 22 Track and Joint Tie 23 Road Track Details 24 Paving Mixer 25, 26, 27, 28, 29 and 30 Pump Plant 30 Batch Transfer 31 Subgrading Machine 32 Platform Car 33 Concrete Mixers for Culverts 33 Clam Shell Buckets 34 Bulk Cement 35 Tunnel Storage 35 Tunnel Traps 35 Grout Mixer 36 Tables 37 Lakewood Industrial Haulage 38 Lakewood Construction Plant 39 Installation of Lakewood Road Plant. . . 40 Bulletin No. 2Q-D Page 3 r Phe Lakewood Engineering Co. Bulletin No. 29-D Page 4 About the Lakewood Engineering Company The Lakewood Engineering Company was organized in 1896. The business showed a normal growth until late in 1914. Since then the expansion ot the company in the development or absorption ol other companies has been rapid. The Duplex Manufacturing and Foundry Company, of Elyria, Ohio, was purchased to give the Lakewood Company its own source of castings. The Milwaukee Concrete Mixer Company became associated with Lakewood in the early part of 1917, fur- nishing, through its plant, additional facilities for the manufacture of mixers. The Marsh-Capron Manufacturing Company, of Chicago Heights, manufacturers of mixers, entered into a similar arrangement in 1918. The Gabon Dynamic Motor Truck Company, of Gabon, Ohio, was purchased outright in the fall of 1917. The rapid development from a comparatively small business in 1914 to millions in 1919 has had as its most interesting and outstanding fact the remarkable ability of the personnel of the organization to grow as fast as the business. Coupled with this rapid growth and unusual ability is a reputation for loyalty and whole heartedness in the Lakewood organization which is commented on by all visitors. This spirit, we believe, encourages more satis- factory business relations, real co-operation and service. The Lakewood Engineering Co. Bulletin No. 2q-D Page 5 Foreword T HE present demand for hard surface roads is out of all pro- portion to our ability to satisfy it. Engineers who must build new roads, and at the same time maintain the old ones, are confronted by the question of how to get the roads built rather than by the problem of raising money. It is estimated that it would require 166 2 ^ years to improve all the present mileage at the 1909-1915 rate and 33 years to improve the necessary minimum of at least 20 per cent. Very evidently the business of constructing roads must be put on the same quantity production, uniform quality, cost-reducing basis as our other manufacturing industries. Quantity and quality production is possible in our manufac- turing plants because the work is systematized. Machines have been substituted for manpower; each worker is given definite tasks to do — day after day — and, by repeating these tasks, becomes highly efficient. Every effort is made to produce a large quantity of uniformly good quality at the lowest possible cost. In the manufacturing plant raw material is received and stored in a warehouse. This supply of raw material may be great enough to keep the plant running for a month or more independent of railroad deliveries. From the warehouse the raw material is moved to the producing machines, goes through the manufacturing processes until, finally, the finished product is ready for the user. So, manufacturing processes can really be divided into four operations: 1. Receiving and storing raw material. 2. Transporting raw material to manufacturing machines. 3. M anufacturing. 4. Delivery of the finished product. The principles on which the operation of the concrete road plant developed by The Lakewood Engineering Company are based are very similar to those which the successful manufacturer follows. Instead of pig iron and coke, the concrete road manufacturer has, as his raw materials, sand, stone and cement. These he must unload and store, providing large enough storage space to make his road factory independent of irregular deliveries of raw material. The Lakewood Engineering Co. Bulletin No. 29-D Page 6 Instead of hauling pig iron and coke to the cupola, the manufac- turer of roads hauls sand, stone and cement and pumps water to his manufacturing machine — the concrete mixer. And as the steel manufacturer melts the iron and perfects his finished product, so the manufacturer of roads puts sand, stone, cement and water into the concrete mixer and produces his finished product — concrete road. The fourth step- delivery to destination — is, for the road manu- facturer, a simple matter, as the distance his product must travel, is, at most, the length of the boom on the paving mixer. The Lakewood road manufacturing plant involves the use of machines instead of manpower. Quantity manufacturing of roads is made possible. Cost of handling and rehandling raw materials is cut to the bone. Waste of materials during the manufacturing process is eliminated. Labor is made more efficient and labor turnover reduced. Uniformity of product is assured at no extra cost. And a better product results- -a denser , smoother , longer-service concrete road. Details of operation and description of the equipment used in manufacturing roads by means of the Lakewood system are given in the following pages. It is hoped that this foreword will help to emphasize the simi- larity of road manufacturing to the manufacture of any other com- modity, and will help the reader to visualize the application of modern industrial efficiency to the road manufacturing industry— an industry in which quantity production and uniform quality have never before been achieved. And because the use of Lakewood plant makes possible the production of good concrete roads in large quantity, in much the same way as our modern industrial plants operate, we say that with Lakewood plant the contractor matiufactures concrete roads. The system is easily applied to laying concrete bases for brick or asphalt roads. The Lakewood Engineering Co. Manufacturing Concrete Roads With Lakewood Plant (A Description of the Method Employed) Bulletin No. 29-D Page 7 The manufacture of concrete roads with Lakewood plant may he divided into four operations: 1 — unloading the raw material (sand, stone and cement); 2 — hauling this material to the mixer; 3 — mixing the con- crete, and 4 — finishing the road surface. Applying the principles of good factory management, the unloading plant must be able to unload quickly to avoid demurrage charges, store enough material to make the operation of the plant independent of railroad delivery, and designed to elimi- nate waste and costly rehandling. Unloading and Storing Raw Material Contrary to the practice of stor- ing material on the grade, the Lakewood method involves the use of a cen- tral unloading and storage plant. Typical layouts that can bevaried to meet different require- ments are shown on pages 10 and 11 . When the layout shown on page 10 is used, gravity storage bins are placed at intervals along the railroad siding with narrow gauge track running under the bins, past the cement shed and thence to the mixer. The material is transferred from cars to bins, or cars to stock piles, by means of a clam shell bucket hung from a locomotive crane. Space for stock piles is provided, as in- dicated, to take care of material in excess of the bin capacity and to allow storage of enough material to make operation in- dependent of railroad delivery. The stock pile capacity does not have to be so large as when hauling is done on the sub-grade as only a few stock piles are required and the same piles are used throughout the job. When bag cement is used the bags are transferred from the railroad cars to the cement platform or shed by hand. If bulk cement is used, the cement platform is unnecessary. The bulk cement is received in gondola cars, properly protected by a tarpaulin or tar paper housing. By replac- ing the cement shed with gravity bins and fitting the bins with removable water-tight cov- ers to permitthe entrance of the clam shell, the cement can be unloaded by the bucket. At this central loading plant sand and stone are poured from the gravity bins into road cars or batch boxes having separate and properly pro po r t i on ed compartments for sand and stone and a water-tight box for cement. After a train is loaded with sand and stone it is moved past the cement shed, where the cement boxes are filled. Whether bulk or bag cement is used, the cement boxes are filled at the central loading plant, covered with a water-tight lid, and the correctly proportioned batches are ready to be hauled to the mixer. As no cement leaves the storage shed, ex- cept in the water-proof box in the road car, no sacks are taken out on the grade, saving the cost of taking care of the sacks. As the locomotive crane is the first The Lakewood Engineering Co. Bullet hi No. 29- D Page S Clam shell bucket hung from crane transfers materials to bins ami Storage piles. Costly rehandling is avoided. equipment on the job, it can be used to unload other machinery. The material plant can be made ready and operations begun while grading is being done. And as soon as a part ol the grade is finished, con- crete placing can be started. Having a flexible, large-capacity plant, capable ot utilizing the entire length of the railroad siding, the work is made practically independent of irregular mate- rial deliveries. And with this type of plant practically no hand labor is required and rehandling of material is reduced to a minimum. barge storage piles permit quick unload- ing, and it is, therefore, possible to re- lease sand and stone cars immediately, th us avoiding demurrage charges. The unloading can be done regardlessof weath- er conditions, which is a decided advan- tage over the practice followed in the past. )nce the materials are unloaded the cost of lading them into road cars is practically nothing and the loading is independent of the crane. Furthermore, no money is spent for hauling until the materials are actually needed at the mixer. And as practically all of the sand and stone can be used (due to having only a few big stock piles) waste of material is avoided and aggregates are kept clean. The unloading plant shown in the lay- out on page 10 is for use where bins are used. The tunnel arrangement shown on page 1 1 is a variation to meet the con- tractor’s requirements. Hauling Batches to the Mixer No construction work is stopped so completely by wet weather as con- crete road work, when materials are hauled on the sub-grade in wagons or trucks. Hence, the method ad- vocated by The Lakewood Engi- neering Company eliminates haul- ing in wagons or trucks and in- volves the use of specially designed road cars and narrow gauge track, as indicated by the layouts on pages 10 and 1 1 . Contractors usually endeavor to overcome the disadvantages of Work was stopped on this road because the grade was too wet to permit hauling. Cars and track prevent such delays. The Lakewood Engineering Co. Bulletin No. 29-D Page 9 Track can be laid on shoulder or sub-yrade, thus giving flexible operation to meet every condition. The center picture shows a train operating in wet weather when hauling over sub-grade in trucks would be impossible. hauling on the grade in wet weather by stocking sand and gravel on the finished sub- grade as far ahead of the mixer as possible. But in doing this the contractor is only partially insuring a supply of the necessary materials. Seldom is cement stored in quantities on the grade. Water is never stored on the grade. Therefore, storing sand and stone, but not storing cement and water, does not, by any means, free the con- tractor from delays caused by lack of material at the mixer. The sub-grade is simply used as a place to stock pile part of the material. No more wasteful place could be chosen for a stock pile. To be able to haul on the grade with wagons or trucks a long stretch is usually graded. Bearing in mind that the hauling will have to stop when rain comes, con- siderable quantities of sand and gravel are stocked on the grade before concrete plac- ing is begun. This results in a loss of one or two months of valuable time out of a season, before the actual laying of con- crete is begun. By using a central loading plant, un- loading of materials and the grading can be started simultaneously . And as soon as (Continued on page 1 2) The Lakewood Engineering Co. Bulletin No. 2Q-D Page io This plant has the following characteristics: Single track siding; traveling crane having full circle swing handling a clam shell bucket; storage bins for sand and stone from which to load narrow gauge cars; house in which to store cement in bags; narrow gauge track with passing siding on sub-grade. Stock piles should be large enough to permit operating the unloading plant for several days before hauling begins. The crane unloads sand and stone direct from railroad cars into the bins. When the bins are full and the narrow gauge rail- way is not operating, the crane immediately un- loads from the railway cars into the stock piles and in this way eliminates demurrage charges. If, on the other hand, the narrow gauge road is operating when no cars have been received from the railroad, the crane rehandles material from the stock piles into the bins. Thus the unloading is independent of the hauling and may proceed regardless of weather conditions or time of day. These features make this type of unloading plant most economical when the yardage to be handled justifies the plant investment. Bags of cement are stored in the cement house or are emptied directly into the road cars. Hop- pers with bin gates and measuring devices may be used economically under certain conditions. A train of cars is pushed under the stone bin and the stone compartment in each car is filled with that aggregate. The train is then moved to the sand bin and the sand compartments are filled. The watertight cement compartments are filled and the train is ready to be hauled to the mixer. The locomotive places the loaded cars on the track as shown. Cars are handled either singly or in pairs over the stub end of the track to the mixer. The batch transfer lifts the car bodies and dumps them into the mixer as described on pages 12 and 13 . The empties are pushed onto the passing siding. Laying the track on the sub-grade is not recom- mended. Where possible it should be laid on the she julder, as shown in Layout M-232. When track is on the subgrade it is necessary to move the switch nearest the mixer two or four times a day. This causes delay. I'he switch of the passing siding farthest from the mixer should be lifted, at the most, once a day or, under certain conditions, every second or third day. Laying the track on the sub-grade is necessary when going over the bridges that have to be paved, through cuts, or in other places where there is not sufficient width of shoulder. With a revolving crane handling a 1 -yd. Lake- wood clam shell bucket for unloading, it is pos- sible to handle about 300 cu. yds. of sand and stone a day. This is sufficient to supply, to max- imum capacity, a No. 14 E paver. The /.akewood Engineering Co. Bulletin No. 29 -D Page 11 The characteristic features of this plant are: A double track siding on which material cars are received which shortens the length of yard; a movable derrick handling a l^-yard clam shell bucket; sand and stone piles of very large size, through which is run a tunnel; and a storage house for bulk cement; and the use of two concreting outfits. The bulk cement is unloaded with a clam shell bucket and lowered through hatches in the roof of the cement storage house. This method of storing materials provides for much larger storage capacity than Layout M-231. Sand and stone piles may be accumulated during the winter, or many months before the work is ready to go ahead. T his feature enables the con- tractor to obtain his materials at a reduced price and eliminates shut down due to irregular deliver- ies. The tunnel is built of timbers. A design will be supplied upon request. The tunnel is pro- vided with bin gates or traps in its roof, so that a large percentage of the stored materials will flow by gravity through the traps. The cement stor- age house has traps in its floor. As the trains of road cars travel through the tunnel they are loaded with sand and stone by tripping the traps in the roof. These traps are spaced uniformly so that each car is served by its own trap, thereby reducing the need for car spotting. This plan shows how two mixers may be used on a typical road job where the unloading plant is located at a point near the center of the road job. One mixer works on a long haul toward the unloading plant, and the other mixer works on a short haul away from the unloading plant. As the haul shortens for the first mixer the track is taken up and relaid ahead of the second mixer. It is possible to use two mixers in this way when the shoulder of the road is wide enough to accom- modate the track. At least 4 ft. of shoulder is necessary. Passing sidings for cars may be laid on the sub- grade, as shown at “A”, or thrown over toward the ditch or into a field as at “B”. The arrange- ment of these passing sidings must in every case be determined by the layout of the road under construction. Passing sidings, as at “C”, must be provided as close to the storage piles as possible. Others should be laid along the main road so that out- going loaded trains may pass incoming empty trains. This type of plant can be designed for larger capacities than are possible with Layout M-231, and an unloading plant big enough to take care of two mixers can be made a comparatively simple proposition. The characteristics of Layouts M-231 and M-232 are interchangeable. The best arrange- ment of plant for any job cannot be definitely stated but should be carefully determined before equipment is purchased. Lakewood Engineers are always at the customer’s service to assist in studying conditions and designing suitable plant layouts. The Lakewood Engineering Co. Bulletin \No. 2Q-P Page 12 FIG. 1— Bail Attached to Car Bodv a short part of the road is graded con- creting can he started. This lengthens the working season considerably — usually one or two months. By starting the grading and concrete placing at the point nearest to the unloading station, work is begun with the dif- ferent parts of the job close together and under the supervision of one man. The mixer can start operating as soon as a part of the grade is fin- ished. I he hauling will not interfere with the grading, nor with the method employed in grading. In this way the job is begun with the shortest haul and the easiest working con- When the long haul is finally reached, the track has been thoroughly imbedded and is better able to stand the long haul than newly laid track. In this way the grading can be completed immediately in front of the mixer and the grading and placing of concrete can be done simultaneously, throughout the entire season. This natur- ally lengthens the working season by be- ginning concrete work a month or two earlier than usual. Bv not hauling over the grade a truer, more even grade is obtained and no mate- rial is wasted by filling up ruts caused by hauling. The sub-grade, once finished, needs no more attention. The road construction track can be laid on the shoulder of the road wherever the shoul- der is at least 4 ft. wide. This makes itunnecessary to move the track as the mixer moves forward. For the same reason, where there is additional width on the shoulder, it is best to put the passing track outside of the sub-grade. By hauling in cars on track, material can be re- ceived and unloaded the same day the grading begins. Concrete placing can begin as soon as a part of the grade is finished and can follow the grading ditions. Part of the cars and track can be used for grading before they are all needed to haul material. The haul increases as the work progresses, so that the contrac- tor can estimate, in advance, how much equipment and locomotive power he is going to need when he gets the maximum haul. And as concrete is laid during the first month of operation, the contractor is entitled to a bigger monthly estimate, thus simplifying the financing of the job. There is no necessity for laying a con- siderable length of track at one time. 7 he I.akewood Engineering Co. FIG. 3 — Batch Swung Over Skip Bulletin No. 29-D Page 13 closely. Wet weather does not interfere with hauling or placing concrete, unless it is raining so hard as to damage the surface of the finished concrete. This regularity of consuming material reduces rehandling of material to a mini- mum. Many a job is shut down because of the grade becoming wet and the con- tractor not caring to take the chance of ordering the rest of his material when not sure that he would be able to haul it. Where hauling is done on the grade with wagon or with motor trucks, it is always uncertain whether the unpaved earth will stand up under the travel. Often clay will make part of the haul difficult in wet weather and sand will make other parts difficult in dry weather. Hauling on road track is an absolute certainty and it makes no difference whether the track is rest- ing on sand or mud. By using this method a con- tractor should actually be able to lay concrete twice asmanydaysin theseason as he would by other methods. Mixing the Concrete The operations involved in handling the complete batches as they arrive at FIG. 6 — Skip Raised, Car lowered Onto Running Gear the mixer in road cars are simplified by the use of the Lakewood batch transfer. This is a derrick arrangement attached to either side of the mixer, which lifts and dumps complete batches directly into the charging skip. Theoperations are: 1. Cement cover re- moved. Two men attach Lakewood bail to car body. 2. Mixer operator owers skip. FIG. 5 — Car Body Swung Back Over Running Gear Weight of skip raises car from run ning gear. 3. Derrick is swung around until batch is over charging skip ready to be dumped. 4. Aggregates are dumped into charg- ing skip. 5. Empty car body is swung back over running gear. 6. Operator raises skip to discharge batch into mixer. As skip rises car body is lowered onto running gear. Bail is detached. Cycle of oper- ation is repeated. By using this method complete and cor- rectly proportioned batches are dumped FIG. 4 — Complete Batch Dumped into Skip (Continued on page 16) The Lakewood Engineering Co. Bulletin No. 2Q-D Page 14 The OLD Way Compare These Big wheelbarrow and shovel crews. Sand and stone piled on grade. Aggregates become mixed with dirt ot sub-grade. 5 to 10 per cent, loss of material. Concrete work delayed until great quantity of material can be stocked on sub-grade. Working season shortened. Sand and stone hauled over finished sub-grade in trucks or wagons. Certain amount of refinishing necessary. Cement sacks must be cared for, increasing the contractor’s cost. Cannot operate in wet weather. Operation difficult on narrow roads and only a small amount ot road can be finished in a season. Which Method (i The Lakewood Engitieering Co. Bulletin No. 2 i£ -■ , .1 . - -s • V N . -y . Concrete of this consistency would be difficult to work by hand but the ma- chine handles it easily, as shown below. directly into the charging skip, shovel and wheelbarrow gangs are eliminated, and no sand, stone or cement is piled on the sub- grade. No time is lost shoveling material piles out of the way or bringing extra piles to the mixer. No material is wasted from misfiguring the amount required and shoveling the excess to one side when the mixer passes. The sand and stone are kept clean — not mixed with the dirt of the sub-grade. As the sand and stone compartments in theroad cars hold just the right amount to make a correctly proportioned batch, a uniform concrete mixture is obtained without the cost and trouble of measur- ing each batch. Another big advantage of this method of charging the mixer is that the work of the men is made easier. There is no wheel- ing of sand and stone — no cement sacks to empty. Also, each man has certain duties which he repeats day after day. He learns to do his particular part of the work better than any other man can do it — and be- comes a highly efficient workman. The fact that the work is easier appeals to the men physically. They are reluctant to leave a compara- tively easy job. The labor turnover is thus reduced and the cost of securing new men is saved. And as the work is systematized so that each man performs just one operation and can rest for a minute or so at regular intervals, the few men required will work with high efficiency throughout the day. Tamping and Finishing the Concrete Surface To overcome the difficulty of finishing concrete by hand and to permit the use of drier, coarser mixtures, a mechanical concrete road tamping - finishing machine has been perfected. This device removes the air and water voids from the concrete and permits us- ing a very stiff, dry mixture. The pro- portion of coarse aggregate may be in- creased considerably when this machine is used. This concrete road finisher has three distinct functions: 1 . To spread the concrete as it comes from the mixer to approximately the desired height and crown. 2. To tamp the concrete, remove the voids, to compact the mixture and work the concrete to the finished height and crown. 3. To float the surface of the concrete with a belt to a smooth surface. It performs this work with a saving of labor and at a faster speed than is possible by hand methods. A — At Vi r 5s? rr¥ b8a#*v!' a at : -- - The Lakewood Engineermg Co. Bulletin No. 29-D Page 17 The machine travels forward and backward under its own power. A member called the strike-off spreads the concrete to approximately the necessary height and crown. The tamper, located just back oi the strike-off', tamps the con- crete, the first time over with a long, hard stroke; the second time with a short, rapid stroke, which may be varied until the concrete is being subjected to continuous agitation as the machine moves back and forth. The stroke of the tamper is regulated by the operator and may be varied for different consistencies of concrete as well as for different stages of progress. The float, located at the rear of the machine, produces a smooth finish by sweeping a belt across the surface at a comparatively slow speed. Some engi- neers prefer to omit the floating and have used the finisher without the belt attach- ment. They claim that the finish made by the rapid strokes of the tamper mem- ber is better than the surface produced by floating. The tamper finish gives a slightly roughened surface and an abso- lutely true crown. By subjecting the mixture to the con- tinuous agitation caused by the tamper the concrete is compacted and the air in it is brought to the surface as shown on page 18. The larger stones and enough mortar to cement them are brought togeth- er. By increasing the amount of coarse aggregate the contraction of the concrete is greatly reduced. The voids are thus eliminated, and a concrete of mechanically uniform consistency is produced. This treatment, of course, results in a stronger concrete, as has been proved by Prof. Duff A. Abrams in his experiments at Lewis Institute, Chicago. Prof. Abrams has proved that 30 per cent, too much water reduces the strength about one-half and twice the correct amount of water gives a concrete of only one-fifth the strength it would have if just the right amount of water were used. With hand finishing it is necessary to use water in large excess. If this extra amount of water is not used the concrete will be so stiff' as to present difficulties in finishing. The excess water reduces the strength realized from the cement and brings the inferior materials and scum to the top, pro- ducing a poor wearing surface. The Lakewood Concrete Road Finisher permits the use of a drier, coarser mixture than could be worked by hand. So dry a concrete can be worked with this that mix- ing can be done at a central mix- ing plant and the concrete hauled long distances without separation The Lakewood Engineering Co. Bulletin No. 2Q-D Page /S of the aggregates. The agitation caused by the tamper is so violent that it amounts to remixing the concrete and causes more perfect hydrating of cement. Only one man is needed to operate the Lakewood Road Finisher. Because of the arrangement of the controls the machine can be operated from either side of the road. Hence, one man with the Lakewood machine and two helpers with spades can, when working dry concrete, do the work usually done by eight or nine men -atid make a better road. Mixing at Central Plant Conditions on road jobs are sometimes such that savings can be effected by mix- ing the concrete at a central plant and dumping mixed batches from cars onto the sub-grade. This is particularly true when concrete is laid in freezing weather when the materials must be heated. Probably the biggest obstacle to the use of this method has been working a concrete of consistency that would permit hauling any considerable distance without separation of the aggregates. The objection that such concrete can- not be worked properly after a long haul is overcome by the use of the Lakewood Concrete Road Finisher. So violent is the action of the tamping member that the concrete is practically remixed, resulting in more perfect hydrat- ing of the cement and compacting the concrete after the initial shrinkage has taken place, reducing hair checks and other defects due to contraction. So dry a mixture can be used that the sepa- ration of the aggregates is practically impossible. By using such concrete so firm a surface is produced that it can be covered with straw or hay immediately. The Lakewood road car body can be used to haul mixed concrete by removing the cement box. When dumped by a der- rick this car body can be turned squarely upside down. The body being V-shaped, with a round bottom and sloping ends, dumps the concrete cleaner than any other shape of bucket. The plant layouts shown on pages io and 1 i may be easily adapted to central plant mixing. least resistance; air again compressed nearer surface; air bubble breaking through surface; air entirely removed. The Lakewood Engineering Co. Bulletin No. 29-D Page 19 y. • ; d ; T^P/,y |Tj - ■ ! ■' ’ • • kjXfo ^ ^ :• » •< } :‘J ft* * % A : \Ujk >gujv v *i»- - . **• V'P’V; • AbH'b'j A'A Tfr* • *v * > 1 1 r . * ‘ *"• */' ' l { - v*' * -4 '•>>* * ; f ‘-i yhnh'pSfiii ■y-y.y. Equipment Used In Building Roads With Lakewood Plant The following pages give detailed descriptions of the equipment needed for the operation of the Lakewood Concrete Road Plant. The method of using this plant is outlined in the preceding pages. A more comprehensive appreci- ation of the advantages of using the Lakewood plant will be gained if the preceding pages are read carefully. The equipment shown on pages 20 to 35, inclusive, is, we believe, best suited to do the work it is in- tended to do. Each unit has been designed and built to work with the other units, thus giving a com- plete plant that will operate smoothly and earn maximum profit for the user. .*• s » < v > « <■ s . ; v. • iih L_ ww — , — , — m ■ A'VU.Am’ • H m • f? 1$ i ffite ^ . ■ 3 ■■ - , „ . • ■ ; ■ - h • ■ ■ : h ■ ■ ■ Mn - ■ i w< ■ • . . . ■ ; - ; . ; 'S ■ 'y\ ; ■ ' } ':■■■' : ' - ' . , . - . . ■ ■ . ' - ■ * , . . | ' • 1 , ■ v. * • • - -# • * . • . ' ‘ / '• ' k; r ■ *■ 1 1 ’ * /-t * 'i • * ? v t .‘ > • \ * The Lakewood Engineering Co. bulletin No. 2Q-1) Page 20 The Lakewood Road Car This road car is fitted with a watertight cement box which is bolted into place to divide the car into separate compartments for sand and stone. In this car properly proportioned sand, stone and cement are hauled from the central loading plant to the mixer. The watertight cement compartment is bolted into the V-shaped body at a variable distance from either end of the car to give any desired proportions. The cement box is, of course, provided with a removable watertight cover. These road cars are fitted with a trunnion arrangement on the ends of the body so that the car body can be lifted from the running gear by means of the Lakewood Batch Transfer shown on page 21 . By removing the cement box the Lakewood Road Car can be used as a V-Dump car for hauling mixed concrete or dirt. By removing the body the rocker supports are used as bolsters on which to carry forms, pipe, track, etc. Thus the Lakewood Road Car is three cars in one. These cars are equipped with spring drawbars and bumpers to permit easy start- ing and hauling in long trains. They are also fitted with spring pedestals to prevent derailments and reduce the shock to cars and track when hauling heavy loads. Cage roller bearings make possible moving heavy loads with least tractive effort. F.xtra heavy 12-in. wheels give easy riding and hauling in long trains. Twenty-four inch track gauge is standard. The Lakewood Engineering Co. bulletin No. 29-D Page 21 Lakewood Batch Box Cars and Batch Boxes Lakewood batch box cars or running gears are equipped with spring draw bars, spring bumpers, spring pedestals and Hyatt roller bearings. Heat treated steel axles, selected after a thorough investigation of the effects of rapid reversal of stress caused by locomotive haulage, insure long, uninterrupted service. This Lakewood car represents a big advance in industrial car design. Two sizes of batch box cars are available, one for carrying two 25 cubic foot ca- pacity boxes, and one for two 25, 29 or 37 cubic foot capacity boxes. The tip-over batch boxes are made of steel plate and are loaded and handled with the Lakewood batch transfer in the same manner as the road car. A separate container for cement divides the box into compartments of proper size, which when filled with aggregates and cement, give a batch of proper size and pro- portions and prevents the mingling of aggregates and cement. The small cut above shows two 25 cubic foot capacity batch boxes on the light running gear and the larger cut shows batch boxes of 29 or 37 cubic foot capacity on the heavy running gear. The Lakewood Engineering Co. Bulletin No. 29-D Page 22 To 13 The Lakewood Concrete Road Finisher The Lakewood Concrete Road Finisher has three distinct functions: 1. To spread the concrete as it comes from the mixer to approximately the right height and proper crown; 2. To tamp the concrete to eliminate all voids, and compact the stone or gravel aggregate to give a concrete of great density and strength; 3. To finish the surface of the concrete with a belt to a smooth, even-riding surface. It performs this work with a saving of labor, at a fast speed. The resulting concrete is more uniform as to strength and wearing qualities than is possible when hand methods are used. The machine consists, briefly, of a trussed bridge over the road, supporting the 4 h.p. gasoline engine power plant and driving mechanism in a dust proof housing. The bridge is carried on end frames having two wheels each, traveling on the side forms. A strike-off with a metal edge, (adjustable to the crown of the road) and having a reciprocating horizontal movement across the road is dragged by arms pivoted on the axles of the front wheels. Hung behind the strike-off, on laminated springs, is the tamper. This consists of a heavy timber (kiln dried and oil soaked) shod with a steel channel. After many experi- ments this has proved to be the best construction for the purpose. The tamper has a snappy down-and-up movement and hits the concrete for the full width of the road with a blow, the force of which is easily varied to suit the consistency of the concrete and the condition of its surface. The finishing belt is attached to a supporting frame at the rear of the machine, from which it is easily removed for cleaning, reversing or renewing. The frame is shaped to the crown of the road and moves the belt slowly back and forth across the road. The finisher travels forward and backward under its own power, along the side forms. The speed forward is 7 ft. a minute; reverse, 28 ft. a minute. All operations of the machine are controlled from either side of the road by a simple system of levers. The machine can, therefore, be easily operated by one man. Side forms on which the machine travels may be the 2 in. boards often used, or any one of the several types of metal forms now on the market. The only requirements for the machine are that the forms rest solidly on firm ground or be supported by short stakes driven into the ground under them. 'The Lakewood Engineering Co. bulletin No. 29-D Page 23 Lakewood Road Track and Joint Tie Narrow gauge track for road work is ot the most temporary kind and must be laid down and taken up repeatedly. This necessitates a track strong enough to stand this repeated rough han- dling. The track must also have enough bearing surface to support it on natural ground without ballast. Lakewood Road Track meets these require- ments. The rails are supported by a large, pressed steel tie with end flanges, developed for use on the European battlefields where track was laid and successfully used on extremelysoft ground. These ties are riveted to the rails to insure a rigid track section, which cannot shift by one rail taking a lead over the other, or ties slipping out of position. The groove in the old style rolled tie collects rain water and causes puddles under the ends of ties on the low side of the track. This softens the support- ing ground at the most vital spot. This defect has been overcome by the Lakewood pressed steel tie with a flange on the end as well as on the side. The Lakewood tie gives unusually large bearing surface outside of the rail as well as inside, thus eliminating buckling and permitting track to be used on extremely soft ground. Frequent moving of road track makes it prac- tically impossible to keep bolts in good shape and fish plates bolted on tightly. The common cus- tom has been to use a slip sleeve, or simply bolt fish plates to one section. This does not make a reliable splice, nor does it support the track im- mediately at the joint. To overcome these objections Lakewood has developed the joint tie shown for joining road track together. It clamps the rails and supports the j oint. The tie and clamps are riveted to- gether and make one solid piece too big to lose easily and too rugged to be damaged by handling. T his tie takes the place of four fish plates, eight bolts and eight nuts — twenty pieces in all — with no threads to get out of order and no bolts to come loose. Various track and switch sections and spec- ifications are shown in detail on the following page. The Lakewood Engineering Co, The Lakewood Engineering Co LAKEWOOD ROAD TRACK DETAILS Bulletin No. 29-D Page 25 The Lakewood-Milwaukee Paver The Lakewood-Milwaukee Paver has kept pace with the growth in popu- larity of concrete as a material for permanent pavements. It has been im- proved from year to year to make possible placing more concrete of better quality in a given time. The machine is remarkable in its design for such details as: 1. A differential gearing on the rear axle to permit turning in narrow streets or roads, as with an automobile. 2. A power steering device that permits the operator to guide the machine with much less effort and much more truly than with the old-fashioned hand wheel. 3. A highly developed steam engine to drive the machine, which has many unusual features, as described on page 30 . 4. An unusually convenient arrangement of all levers, so the engineer can control every operation of the machine without moving around the platform. 5. Extra wide (14 in.) wheels to give large bearing surface. Lakewood-Milwaukee Pavers are driven by either steam or gasoline power and are equipped with distributing boom and bucket or with gravity chute. The length of the boom is 16 ft. and the bucket holds a complete batch of 14 cu. ft. of mixed concrete. The distributing bucket bottom doors are operated by a tripping and closing device developed especially for these mixers. It is not dependent on the tension of the cables, which may be comparatively slack. Any stretch in the cables is automatically taken up on the winding drums. The bucket may be run out to any point on the boom and stopped without danger of opening the bucket sooner than desired. The mechanism does not open the doors until the bucket starts on its trip back to the mixer. The doors then stay open until just before the mixer is reached, giving plenty of time for the batch to flow completely out of the bucket. There is, therefore, little danger of jamming the doors with stones. Doors are heavily braced to withstand hard service, and hinges are arranged so concrete does not overflow them. Gravity chutes are sometimes preferred on narrow street or road work. The gates are easily operated and if concrete is mixed with the proper amount of water it will easily flow down these chutes. The mixer end of chutes is widened to prevent splashing of concrete as it flows off the mixer discharge spout. Size No. 14, with boom and bucket, is recommended for use with the Lakewood Road Plant. This has a capacity of 14 cu. ft. of mixed concrete per batch. This is the most popular size with city paving contractors put- ting in concrete base for various pavements. On this work the machine generally mixes a 2-bag batch of 1-3-5 or of 1-3-6 concrete. The Lakewood Engineering Co. Bulletin No. 2 Channels — Length, 93" — Width through engine and boiler platform, 106". Engine Platform — 54 ” Steel Plate. All-Steel Truck — 3-point suspension. Wheel Base, 85"- — Tread, 70". Front Axle, 2-6" 13 lb Channels, with b lilt-in high carbon steel axles, 2f|" diameter. Rear Axle Shaft — High carbon steel, 3}f " diameter Front Wheels— 28" x 14" tread. Drum Countershaft — Cold rolled 2 i 7 s " diameter. Engine Countershaft— Cold rolled 2 is" diameter. steel, steel. CLOSED WATER TANK Capacity, 30 gallons. Length, 28" — Diameter, 18". Intake, 154"— Outlet, 254". ELECTRIC MOTOR Any standard make — 15 H. P. — 900 R. P. M. preferred. Cut steel reduction gears. BOOM AND BUCKET 18 ft. Boom — 14 cu. ft. Bucket. 20 ft. Boom— 10 cu. ft. Bucket. Diameter, 16". Face, 354”. Length of Bearing, 12". Tracker Shafts — Cold rolled steel, 2, diameter. Rear Wheels— 34" x 14" tread. Driving Sprockets bolted to rear wheels. Cleats on wheel treads. CLUTCHES AND COUNTER- SHAFTS Milwaukee Internal Expanding Toggle Clutch. Lined with non-burning automobile brake lining. STEAM ENGINE (.See pare 10 ) Rated Horse Power, 12 — Bore, 8 — Stroke, 8" — Speed, 175 R. P. M ;> Steam Opening, 1}4" — Exhaust, 2 . Flywheel, 30" diameter x 4" face. Crank Pin, 2 54" diameter. STEAM BOILER Diameter, 36"— Height over all, 84". Rated Horse Power, 14. Shell, A" fire box steel; head, 3/s . Tubes— 63, 2" lap welded, 56" long. Heating Surface— 140 square feet. Furnace, 27" high— 3154" diameter. Grate Area — 5.1 square feet. Traction Gearing Travel forward or backward is controlled by only two levers at the operator’s platform. One lever is for the gear shift governing the direction of travel and the other lever controls the friction clutch. There is a chain and sprocket drive to each rear wheel. Power is trans- mitted to these chain drives through a set of differential gears in a cast steel, oil-tight, dust- proof housing. The differential permits turning the machine on very narrow roads without any slipping of the wheels, thus avoiding strains on the rear axle and driving mechanism. The Lakewood Engineering Co Bulletin No. 29-D Page jo * *1.1 ak i\ ^ Lakewood-Milwaukee Steam Engines Lakewood-Milwaukee Steam Engines used in the Pavers are of the vertical slide valve type. The crosshead guides, center crank and connecting rod end, as well as the piston rod and stuffing box, are protected from cement and dirt by two side plates, held to a tight fit to the engine frame by hand latches. The life of the engines is accordingly greatly increased and repair bills are reduced to a minimum. All lubricating points are easily accessible. The flywheel is of the solid disc type instead of being built as a wheel with spokes. This is a good “Safety First” feature. The flywheel is, moreover, counterweighted to balance the weight of the crank piston, connecting rod, etc., so the engine runs smoothly and without vibration. Lakewood Road Pumping Plant To meet the needs of the paving contractor, the Lakewood Engineering Company has developed a pumping outfit which will insure a full supply of water with the chances of a shut-down of the plant reduced to a minimum. This plant consists of two separate pumping units mounted on one truck. Each unit consists of an outside packed plunger pump driven by a Novo engine and is capable of delivering 1800 gallons per hour with a pressure of 225 pounds per square inch at the pump. The pumps may be connected so that the supply is 80 gallons per minute at a pressure of 225 pounds per square inch. The advantages of a double pumping plant are manifest. A constant supply of water is insured, for even if one unit should break down, the other pump and engines would supply water to keep the job running. Failure of water supply has caused many paving jobs to be shut down tem- porarily with a resulting loss to the contractor. The Lakewood pumping plant is good insurance that the job on which it is working will not have to be closed for lack of water. The Lakewood Engineering Co. Bulletin No. 29-D Page 31 The Lakewood Batch Transfer The Weight of the Skip is the Lifting f orce By means of the Batch Transfer on Lakewood Paving Mixers, com- plete batches are dumped directly into the charging skip as discussed on pages 12 and 13. The device permits the use of a standard front-charge Lakewood paver without incapacitating it for wheelbarrow or other methods of charging. No extra power is required to raise and lower the road car bodies. The lifting is done by the weight of the descending skip. Power is thus used that would otherwise be wasted. There is no hoist to operate. Operations are timed properly and it is impossible to drop the load or raise it at the wrong time. The derrick is carried on two wheels, as shown, thus relieving the mixer frame of any undue strains. This independent support feature permits attaching the derrick to either side of mixer in a few minutes. Any stress set up by the derrick and its load is carried by a heavy channel directly to the rear axle. By means of a tilting adjustment, the derrick is kept in working position on varying grades, inclined so that the load will swing over the charging skip by gravity. The Lakewood Engineering Co. Bulletin No. 29-D Page 32 The Lakewood Subgrader The Lakewood Subgrader was developed to provide contractors with a means of cutting an absolutely accurate subgrade at a minimum of expense. A series of V-shaped knives 6 inches wide and varying from 2 to 4 feet in length, are mounted beneath a wooden framework. This frame is supported by rollers run- ning on side-forms. The operation of a hand lever raises the machine on a pivot until free of the forms. It is then easily reversed or swung so that the roller may pass. The earth shaved off by the subgrader ispiled in windrows convenient for handling The subgrader is raised and swung on a pivot to pro- vide parsing room for the roller The same crew sets the forms and operates the subgrader. The old subgrading crew is almost entirely eliminated. There is a reduction of 50 per cent in the labor and cost of subgrading. I'he machine is pulled by a road roller, which is a necessary part of the sub- grade outfit. While pulling the subgrader, the roller packs the loose material spread by the shovelers to fill inequalities. 1 he finished subgrade is true to within Ms-inch of the engineer’s profile. 1 here are good money-saving reasons for using a subgrader. If the subgrade is 1 2 -inch low there is a waste of 146 cubic yards of concrete in a mile of 18~foot road. At $12 a cubic yard this means a loss or saving to the contractor of $1752 a mile. The Lakewood Engineering Co. Lakewood Concrete Mixers for Bridges and Culverts Bulletin No. 2g-D Page 33 LAKEWOOD-MILWAUKEE LOW CHARGE MIXER LAKEWOOD UNIVERSAL MIXER For culverts, bridges, footings and other jobs that are usually included in highway contracts Lakewood Low Charge or Lake- wood Universal Mixers are well fitted. Lakewood-Milwaukee Low Charge Mix- ers have a capacity of 7 cu. ft. (mixed batch rating). Easily moved from job to job. Fast and thorough mixing combined with easy charging make these machines popular for this class of work. Lakewood Universal Mixers are made in only one size to hold 7 cu. ft. of mixed concrete. Machine is gear driven. Gear made of four interchangeable segments. Bulletin 21 gives complete information and specifications. Lakewood Platform Car for General Utility Work Platform cars of the type shown are frequently used for hauling the lighter equipment, moving switches, turnouts, etc., and for transporting brick or bags of cement for culvert work. Every list of equipment should include a few of these general utility cars. Platform 16 / x3 / 4 /r . Capacity 5 tons. Weight 2,000 pounds. Equipped with spring drawbars, bump- ers and pedestals. 3-£ - ‘/If'&rL 3-7 24 r ^- -J rar* TY/=>£