II Iff ■H ■:"■ '- : ■■■'■■ : - '. HHP * H ■■>.. ■ " THE NGHOUS IB ■■:/.v lift struction Rook Class T rL4i2v5 Book.___J/i5j j dm Copyright^ . COPYRIGHT DEPOSIT. • • • 5 N\is THE LIBRARY OF CONGRESS, One Copy Received JAN, 8 1902 Copyright entry ICLASS d XXc No. ** ■) is- COPY B. Copyright, 1901, by The Westinghouse Air Brake Company Pittsburg, Pa. • • •. • • • • • •• ••• •• AIR BRAKE INSTRUCTION BOOK OF THE WESTINGHOUSE AIR BRAKE COMPANY OFFICERS George Westinghouse, - President H. H. Westinghouse, - - - Vice-President E. M. Herr, ----- General Manager W. W. Card, - - Secretary John Caldwell, ----- Treasurer John F. Miller, - - - Assistant Secretary Pittsburg, Pa., 1901 INDEX. Page. Preface, . . . . . .3 Westinghouse Quick - Action Automatic Brake — General Description, ... 5 Nine and One-half-inch Air Pump, . . .11 Eight-inch Air Pump, . . . . 15 Air- Pump Governor, . . . . 19 Main Reservoir, . . . . .22 " G-6 " Engineer's Brake Valve, . . .24 Slide-Valve Feed Valve, .... 32 Old-Style Feed Valve, . . . -37 " D-8 " Engineer's Brake Valve, . . 39 Quick-Action Triple Valve, . . . -47 Plain Triple Valve, . . . . 52 Combined Freight-Car Cylinder, Reservoir and Triple Valve, 55 Pressure- Retaining Valve, ... . 58 Piston Travel, . . . . .61 Automatic Slack Adjuster, . . .64 Train Air-Signal System, . . . 71 High-Speed Brake, .... 76 Automatic Reducing Valve, . . . 78 High-Pressure Control, or Schedule U, . 84 Handling Brakes in Train Service, . . 87 Piping, ...... 93 Lubricants, . . . . . -93 Brake Inspection and Maintenance, . . 94 Foundation Brake Gear, . . . .98 Leverage, . . . . .101 American Driver Brake, . . . .114 Cam Driver Brake, . . . . 117 Locomotive-Truck Brake, . . . .118 PREFACE. The present edition of our Instruction Book is in the nature of a revision of our previous publications. It has been our aim to condense and simplify the descriptive matter as much as possible, and at the same time to present a complete description of the parts and their operation in the air-brake and air-signal equipment. In it will be found illustrations and explanations of the new devices, as well as of any modifications of older appliances which have been made with the idea of furnishing the best possible air- brake and air-signal equipment. We have distributed many thousand copies of previous editions of our Instruction Book among railway officers and employees in this and other countries, the net result of which has been the education of railroad men in the subject of air brakes, to such an extent that we are led to believe that much of the matter heretofore published can be consistently omitted, especially as there are now many other publications which deal with brake subjects at greater length and provide a source of information in de- tail, which may be referred to, if desired. For this reason, the present edition of our Instruction Book has been some- what abridged and presents a terse description of the func- tions and methods of operation of the devices supplied by this company for the equipment of railroads with its air- brake and air-signal apparatus. We shall, in the future, as in the past, be pleased to furnish these books gratuitously, upon request of heads of departments. The Westinghouse Air Brake Co, November, 1901. The American Machinist Press NY. The Westinghouse Quick-Action Automatic Brake* General Description. The Westinghouse Quick-Action Automatic Brake consists of the following essential parts : First — The Steam-Driven Air Pump, which supplies the compressed air. Second — The Main Reservoir, in which the com- pressed air is stored. Third — The Engineer's Brake Valve, which regulates the flow of air from the main reservoir into the trainpipe for charging and releasing the brakes, and from the trainpipe into the atmosphere for applying the brakes. Fourth — The Air Gauge, which, being of the duplex pattern, shows simultaneously the pressures in the main reservoir and in the trainpipe. Fifth — The Pump Governor, which regulates the sup- ply of steam to the pump, stopping it when the maximum air pressure desired has been accumulated in the air-brake apparatus. Sixth — The Trainpipe, which connects the engineer's brake valve with the main-reservoir and with each triple valve in the train, and includes flexible hose and couplings between cars. Seventh — Th* Auxiliary Reservoir, which is supplied with air from the main reservoir, through the trainpipe and triple valve, and stores it for use upon its own vehicle. Eighth — The Brake Cylinder, the piston rod of which is connected to the brake levers in such a manner that, when the piston is forced outward by air pressure, the brakes are applied. Ninth — The Quick-Action Triple Valve, which is (5) 6 WESTINGHOUSE QUICK-ACTION AUTOMATIC BRAKE. suitably connected with the trainpipe, auxiliary reservoir, brake cylinder and pressure-retaining valve, and which operates, by variations of the air pressure in the trainpipe, (i) to admit air from the auxiliary reservoir (and, when required, as will be explained hereafter, from the trainpipe) to the brake cylinder, thereby applying the brakes, and at the same time to cut off communication from the trainpipe to the auxiliary reservoir, and (2) to restore communication between the trainpipe and the auxiliary reservoir, and at the same time to discharge the air from the brake cylinder to the atmosphere, thereby releasing the brakes. Tenth — The Hose Couplings, which are attached to flexible hose and unite the trainpipe of adjoining vehicles. Eleventh — The Pressure- Retaining Valve, which, when used, prevents complete discharge of the air from the brake cylinder, retaining a pressure of fifteen pounds therein when the brakes are released. Twelfth — The Automatic Slack Adjuster, which auto- matically maintains a constant travel of the piston in the brake cylinder, by taking up the slack as the brake shoes wear. Plate 1 shows the usual arrangement of apparatus and piping upon a locomotive and tender, while Plate 2 diagram- matically illustrates, in section, the essential parts of the brake system and their relative location, as usually applied to railroad trains. The operations of the brake are controlled by the triple valve, the primary parts of which are a piston and slide valve. A moderate reduction of air pressure in the train- pipe causes the greater pressure remaining stored in the auxiliary reservoir to force the piston and its slide valve to a position which allows the air in the auxiliary reservoir to pass into the brake cylinder and apply the brake ; a sudden ~-:±.\ ■";• ~V;,Y^'"—~ A^ ^.wwmwww\w CEO OS pO\DUCT0fl?S VALVE :r':o''"it. ,k ±'* WEST1NGH0USE QUlCK-ACTION AUTOMATIC BRAKE. 7 or violent reduction of the air in the trainpipe produces the same effect, but, in addition (if a quick-action triple valve), it causes supplemental valves to be opened, permitting the air from the trainpipe to also enter the brake cylinder, thereby producing a brake-cylinder pressure about 20 per cent, greater than that derived from the auxiliary reservoir alone and producing a practically instantaneous application of the brakes throughout the train. When the pressure in the trainpipe is subsequently increased above that remain- ing in the auxiliary reservoir, the piston and slide valve are forced in the opposite direction to their normal positions, thereby restoring communication between the trainpipe and the auxiliary reservoir and permitting the air in the brake cylinder to escape to the atmosphere through the triple- valve exhaust port, connecting pipe, and pressure-retaining valve, thus releasing the brakes, and at the same time recharging the auxiliary reservoirs. When the pressure- retaining valve is in operation, it arrests the discharge to the atmosphere when the pressure in the brake cylinder has become reduced to fifteen pounds. When the engineer wishes to apply the brakes, he moves the handle of the engineer's brake valve to the right, which cuts off communication with the main reservoir and permits a portion of the air in the trainpipe to escape; to release the brakes, he moves the handle to the extreme left, which allows air to flow from the main reservoir into the trainpipe, restoring the pressure therein. A device called the Conductor's Valve is placed in each passenger car, to which is attached a cord that runs throughout the length of the car. By pulling this cord, the valve is opened and discharges air from the trainpipe, applying the brakes. When the train has been brought to a full stop in this manner, the valve must be closed. 8 WESTINGHOUSE QUICK-ACTION AUTOMATIC BRAKE. Should a train break in two, the escape of the air in the trainpipe applies the brakes automatically to both sec- tions. The brakes are also automatically applied through the bursting of a hose or pipe. In fact, any material re- duction of pressure in the trainpipe applies the brakes, which is the characteristic feature of the Automatic Brake. An angle cock is placed in the trainpipe at each end of every car, which must be closed before separating the couplings to prevent an application of the brakes. A stop cock is also placed in the cross-over pipe leading from the trainpipe to the quick-action triple valve, and also in the trainpipe near the engineer's brake valve, within convenient reach of the engineer. The former is for the purpose of cutting out, or rendering inoperative, the brake apparatus upon a car, if it should become disabled for any reason, and the latter is for cutting out the engineer's brake valve upon all locomotives except the first, in case two or more are attached to the same train. PLATE 3. 108 vHH i ' '. 75 '^ »»■ ~IDA> ii2 -CD NINE AND ONE-HALF-INCH AIR PUMP. (9) PLATE 4. HMNV.UVE9u.-i~8 NINE AND ONE-HALF-INCH AIR PUMP. (10) The Nine and One-half-inch Air Pump* The Nine and One-half -inch Air Pump is shown on Plates 3 and 4. The following description applies to either the right or left-hand pump, the only difference between the two being in the location of the steam and exhaust connections, for convenience of piping. All parts of the two pumps are interchangeable. As will be seen by examining the Plates, the valve gear of the pump consists of pistons 77 and 79, of un- equal diameter, connected by rod 76, which imparts the movement of the pistons to slide valve 83, and this valve in turn controls the steam supply which operates main steam piston 65. The reversal of the motion of pistons 77 and 79 is controlled by reversing slide valve 72, the duty of which is to admit and discharge steam to and from chamber D, at the right of piston 77. Chambers A and C are always in free communication through port e, e f . The reversing valve is operated by rod 71, to which movement is imparted by reversing plate 69, which engages reversing button k on the downward stroke of the steam piston and shoulder j on the upward stroke. Chamber E always communicates with the exhaust in order that no back pressure may occur when piston 79 is forced to the left, and that a partial vacuum shall not occur when the piston is drawn to the right. This exhaust connection is made by means of port /, shown in the main- valve bushing. This port leads from chamber E directly to main exhaust port d, so that chamber E, at the left of piston 79, is always free from steam pressure. When reversing slide valve 72 is in the position shown, chamber D is connected, through ports h\ h, reversing- valve cavity H, and ports/* and f 1 , with main exhaust passage d, d r , d 2 , and there is no pressure at the right of piston 77. 12 NINE AND ONE-HALF-INCH AIR PUMP. As steam enters the pump at X, it passes through pas- sage a } a 1 , a 2 into chamber A, between pistons 77 and 79. Since the area of piston 77 is greater than that of piston 79, it is forced to the right, drawing with it piston 79 and slide valve 83, to the position shown on Plate 3, thus ad- mitting steam below piston 65, through port b, b\ b 2 . Piston 65 is thereby forced upward, and the steam above piston 65 passes through port c, c 1 , cavity B of slide valve 83, port d, and passage d 1 , d 2 , to connection Y, at which point it leaves the pump and discharges into the atmosphere through the exhaust pipe. When piston 65 reaches the upper end of its stroke, reversing plate 69 strikes shoulder j on rod 71, forcing it and reversing slide valve 72 upward sufficiently to expose port g. Steam from chamber C then enters chamber D through port^ and port g 1 of the bushing (Plate 4). The pressures upon the two faces of piston 79 are thus equal- ized, and the piston is balanced. The pressure in cham- ber A, acting upon small piston 79, therefore forces it to the left, drawing with it piston 77 and slide valve 83. With slide valve 83 in its extreme position at the left, steam from chamber A is admitted, through port c 1 , c, above piston 65, forcing it down ; at the same time, the steam below the piston is discharged to the atmosphere through port b 2 , b\ b ) chamber B of the slide valve, port d, d\ d 2 , and the exhaust pipe connected at Y. When piston 65 reaches the lower end of its stroke, reversing plate 69 engages reversing button k, drawing it and reversing slide valve 72 down to the positions shown, and one double stroke of the steam end of the pump has been traced. The movement of steam piston 65 is imparted to air piston 66 by means of the piston rod. As piston 66 is NINE AND ONE-HALF-INCH AIR PUMP. 13 raised, the air above it is compressed, and air from the atmosphere is drawn in beneath it ; the reverse is true in the downward stroke. As piston 66 is raised, the air above it is compressed and passes through port r, r 7 , lifts discharge valve 86 from its seat, as soon as the pressure below the valve is greater than the main-reservoir pressure above it, passes down into chamber G, and thence into the main reservoir through the pipe connected at Z. The upward move- ment of the air piston produces a suction which causes lower left-hand receiving valve 86 to lift from its seat, and atmospheric air enters through strainer W, passes to chamber n below the receiving valve, thence past that valve into port o, and into the lower end of the air cylinder through o 1 , filling the cylinder. In the down- ward stroke of the pump, the effect just described is produced upon the opposite corresponding receiving and discharge valves. The receiving and discharge valves of the 9^ -inch pump should each have a lift of 3/32 of an inch. Directions. In starting a pump, always run it slowly until it be- comes warm ; by that time, there will be an air cushion in the air cylinder and the early steam condensation will have escaped through the drain cocks and the exhaust. The lubricator should be in operation as soon as possible after starting. A swab, well oiled, is essential on the piston rod. The amount of oil to be used in the steam cylinder of the pump depends considerably upon the amount of work per- formed : some pumps require more oil than others. Judg- ment should determine the amount, it being remembered 14 NINE AND ONE-HALF-INCH AIR PUMP. that a saving of ten cents' worth of oil may result in a dollar's worth of wear of the pump. Engine oil should never be used in the air cylinder, as it eventually clogs and restricts the air passages, causing the pump to heat and producing bad results in general ; valve oil gives the best performance. The air cylinders of pumps in heavy service should receive a small amount of oil each trip, and continuous or regular oiling will give the best results. It is an aid to good operation to run a hot solution of potash through the air cylinder three or four times a year. This should always be followed by considerable clean, hot water, and the union should be disconnected at the main reservoir to prevent the potash from working back into the brake system, where it would destroy gaskets. The Eight-inch Air Pump. Plate 5 shows the Eight-inch Air Pump in its upward stroke. 10 is the steam piston and rod ; 1 1, the air piston ; and piston valves 7, piston 23, reversing slide valve 16, reversing rod 17 and reversing plate 18 constitute the valve gear of the pump. Valves 30 and 32 are the dis- charge air valves, and 33 and 31 are the receiving air valves. In service, the pump governor is attached at X and has a suitable pipe connection with the steam supply. Steam enters chamber m, and port k> always uniting chambers 7n and ^, conducts steam from the former to the latter, which contains the reversing valve. When reversing slide valve 16 is in the position shown, steam passes from chamber m, through port h, into chamber e, and thence through port a into chamber d above reversing piston 23. The same steam pressure now acts downward upon piston 23 and lower piston valve 7, and upward on upper piston valve 7 ; but, as the combined areas of piston 23 and lower piston valve 7 are greater than that of upper piston valve 7, the steam forces piston 23 and piston valves 7 downward to the position shown. Steam is admitted to the cylinder through the upper ports in bushing 26, raising piston 10, while the steam above piston 10 passes through the upper ports in bushing 25, thence through port/, /, shown by dotted lines, into cham- ber £*, and out at Y, through a suitable pipe, to the smoke arch, where it is discharged to the atmosphere. When piston 10 has nearly completed its upward stroke, reversing plate 18 engages shoulder ?i and raises reversing slide valve 16 to its uppermost posi- tion, in which port a is closed and, as the cavity in the valve connects ports b and c, the steam above piston 23 is (15) PLATE 5. > a« < > w H Q < O > w w w Q l-H u < u I h o w & Q w I— I o u (56) COMBINED FREIGHT-CAR CYLINDER, RESERVOIR AND TRIPLE VALVE. 57 escape through leakage groove a to the atmosphere at the non-pressure end of the cylinder. Valve 17, usually placed above the auxiliary reservoir, is known as the release valve. A rod extends from the arms of this valve to each side of the car, and pulling either rod unseats the valve and dis- charges air from the reservoir for the purpose of releasing the brake. The Pressure-Retaining Valve* The Pressure- Retaining Valve (Plate 20) is used almost exclusively upon freight cars, except in districts where very heavy grades are encountered, where it is also used upon passenger cars. With the Pressure Retaining Valve in operation, a certain portion of the brake-cylinder pressure may be re- tained to retard the acceleration of the train while the engineer is recharging the auxiliary reservoirs. The pressure of the air reserved in the cylinder is determined by weight 4, which, in the standard valve, is capable of retaining a pressure of fifteen pounds per square inch, which has been found by experience to furnish sufficient retarding power to prevent a too rapid acceleration of the train speed, and to thus provide sufficient time to enable the engineer to recharge the train upon heavy grades. When handle 5 points downward, the valve is inoper- ative for retaining pressure. If the engineer release the brakes when the retaining-valve handle is turned down, the air from the brake cylinder discharges through the triple valve into the retaining-valve pipe (which is screwed into the triple-valve exhaust port), through the pipe to the retaining valve, which it enters at X, and through ports b, a and c to the atmosphere. If handle 5 be turned horizon- tally, as shown on Plate 20, the air is discharged from the brake cylinder through the triple valve, retaining-valve pipe, and ports b, a and b, as before ; but now, port c being closed, it must lift weighted valve 4 and pass to the atmos- phere through the restricted port d. When the brake- cylinder pressure has become reduced to fifteen pounds, the weighted valve becomes seated, and the remaining fifteen pounds is retained in the brake cylinder until handle 5 is turned down. (58) PLATE 20. PRESSURE-RETAINING VALVE. (59) 60 PRESSURE-RETAINING VALVE. The Pressure- Retaining Valve has nothing whatever to do with applying the brake or admitting air into the cylin- der ; it simply locks in the brake cylinder fifteen pounds of the air pressure that has been supplied through the triple valve, and then only if handle 5 has been placed in the horizontal position, shown on Plate 20, before the engineer increases trainpipe pressure to release the brakes. The Improved Pressure- Retaining Valve (Plate 20) has a peripheral cavity extending half way round the key, through which the air has to pass to reach the weighted valve, when the device is in operation. This modification is designed to prevent obstruction of the ports, which sometimes occurred with the old form of construction, in which the cavity was replaced by a slot extending through the key. Failure of the Pressure- Retaining Valve to hold air in the brake cylinder is generally due to a leak in the connect- ing pipe, a frequent seat of trouble being at the union : it may also be due to a leak in the brake cylinder or in the Retaining Valve, but seldom in the latter. The structure should stand vertically ; there should be no obstruction to the removal of the cap ; it should be so located as to be free of access when the train is in motion ; it should be cleaned, but not oiled, every time the remainder of the air-brake equipment receives that attention ; both it and the connecting pipe should be well secured ; a good rubber gasket should be used in the union, and a little flexibility should be provided in the pipe leading to it from the triple valve. Piston Travel. The following are commonly used terms and their definitions. Standing Travel — The distance the piston is forced outward in applying the brake upon a car when not in motion. Running Travel — The distance the piston is forced out in applying the brake upon a car when in motion. The running travel is always greater than the standing travel, the increase being due to slack in loose-fitting brasses, to the shoes pulling down upon the wheels, to play between boxes and pedestals, and to everything of a similar nature that increases lost motion in the brake rigging un- der the influence of the motion of the car. False Travel — An excessive travel momentarily occurring while a car is in motion ; it is due to uneven- ness of the track, or to some unusual temporary strain. The brake- cylinder pressure resulting from a given trainpipe reduction is greater with a short than with a long piston travel. A piston travel of 8 inches results in a brake-cylinder pressure of about 50 pounds, in a full service application of the brake. Inasmuch as running travel is generally about one and one-half inches greater than standing travel, the standing travel should be 6^ inches to secure this result while running. An automatic slack adjuster is the only means of adjusting piston travel so closely ; but, where one is not employed, good practice customarily requires that the standing piston travel on cars should be kept as close as possible to 6 inches. A 10-pound reduction of trainpipe pressure results in a brake-cylinder pressure more than 50 per cent, greater with a 4-inch than with an 8-inch piston travel, ( 61 ) 62 PISTON TRAVEL. Where the piston travel varies throughout a train, a sufficient trainpipe reduction must be made to fully apply the brakes having the longest piston travel ; in releasing, the increasing trainpipe pressure will force the triple- valve piston on the car with an n-inch piston travel to release position first, the one on the car with a io-inch travel next, and so on down, those with the shortest travel being applied with the greatest force and releasing last. It will be clear, therefore, that satisfactory operation can only be secured by uniformity of piston travel upon all cars in a train. If the piston travel be unnecessarily long, the brake-cylinder pressure is thereby reduced and the efficiency of the brakes correspondingly impaired ; in addition, a greater quantity of compressed air is consumed in brake applications than would otherwise be necessary, thereby entailing greater demands upon the air pump, with correspondingly increased wear and tear. If the piston travel be too short, it is apt to be accompanied by dragging of the brake shoes upon the wheels while the brakes are released, and by too high a brake-cylinder pressure, with an accompanying liability of sliding wheels, when the brakes are applied. The proper piston travel is generally that with which there is just sufficient brake-shoe clearance when the brakes are released. As already stated, a standing piston travel of about six inches has been found to customarily meet this requirement. Special conditions undoubtedly oc- cur in certain cases under which a uniformly shorter piston travel may be very advantageously employed ; in such cases, a modification of the brake leverage may perhaps also be desirable, on account of the high cylinder pressures so resulting. In adjusting piston travel, it should be carefully noted whether the brake beams are so hung as to be at the same PISTON TRAVEL. 63 height above the rail when the car is light as when loaded, or are so hung that they are lowered when the car springs are compressed through loading the car and are raised when the load is removed. If the brake beams are always at the same height above the rail, it is safe to adjust the piston travel when the car is either light or loaded ; but if the height of the beams varies according to the load in the car, it is best, whenever possible, to adjust the piston travel when the car is light. If the travel be adjusted when the car is loaded, and the brake shoes are consequently in their lowest position, wheels are very likely to be slid after the car is unloaded, as, the shoes being thereby raised, the shoe clearance becomes less and the piston is not required to travel so far to bring the shoes up to the wheel tread. As a consequence, the piston travel may become too short and, the car then being light, flat wheels are likely to result. If the piston travel be adjusted when the car is light, the shoe clearance becomes increased as the load causes the car to settle. This results, of course, in lower brake-cylinder pressures and, consequently, in inferior brake efficiency ; but the danger of injurious wheel sliding is avoided. Piston travel should be adjusted as uniformly as possible throughout a train, in which case each brake will more nearly do its share of work, there will be fewer flat wheels, and smoother braking will result. The Automatic Slack Adjuster* The Automatic Slack Adjuster is a simple mechanism, by means of which a predetermined piston travel is con- stantly maintained, compelling the brakes of each car to do their full quota of work — no more and no less — thus securing from the brakes their highest efficiency, without the flat wheels which are likely to accompany a wide range of piston travel. This device establishes the running piston travel ; that is, the piston travel occurring when the brakes are applied while the car is in motion ; and, since this is the time during which the brakes perform their work, the running travel is the important one. Hand adjustment necessarily relies upon the standing travel, and it is only coarsely graded, at best, by the spacing of the holes in the dead-lever guide. The Automatic Slack Adjuster is illustrated on Plates 21 and 22, and its operation is very simple. The brake- cylinder piston acts as a valve to control the admission and release of brake-cylinder pressure to and from pipe b (Plate 21 ) through port a in the cylinder, this port being so located that the piston uncovers it when the predetermined piston travel is exceeded. Whenever the piston so uncovers port a, brake-cylinder air flows through pipe b into slack-adjuster cylinder 2, where the small piston 19 (Plate 22) is forced outward, compressing spring 21. Attached to piston stem 23 is a paw r l, extending into casing 24, which engages ratchet wheel 27, mounted within casing 24 upon screw 4 (Plate 21). When the brake is released and the brake- cylinder piston returns to its normal position, the air pres- sure in cylinder 2 escapes to the atmosphere through pipe b, port a and the non-pressure head of the brake cylinder, thus permitting spring 2 1 to force the small piston to its (64) w PL, w D < fed U < U I— H < S O (65) (N w < W h CO D Q < < CO u < S o (66) AUTOMATIC SLACK ADJUSTER. 67 normal position. In so doing, the pawl turns the ratchet wheel upon screw 4, and thereby draws lever 5 slightly in the direction of the slack-adjuster cylinder, thus shortening the brake-cylinder piston travel and forcing the brake shoes nearer the wheels. As the pawl is drawn back to its normal position, a lug on the lower side strikes projection a (Plate 22) on the cylinder, thus raising the outer end of the pawl, disengaging it from the ratchet wheel, and permitting the screw to be turned by hand if desired. To apply new shoes, turn casing 1 to the left, thus moving lever 5 toward the position shown on Plate 21, until sufficient slack is introduced in the brake rigging. To bring the shoes closer to the wheels and shorten the piston travel, turn casing 1 to the right. The screw mechanism is so proportioned that the piston travel is reduced only about 1/32 of an inch in each oper- ation, which removes danger of unduly taking up false travel. Port a should be drilled as indicated on Plate 23. To avoid the necessity of a bracket to support the adjuster, a special cylinder head, provided with a suitable lug, has been designed for that purpose, and is now furnished with truck, tender, and car cylinders, unless other styles be specified. After the slack adjuster has been applied and the pipe tested for leaks, sufficient slack should be introduced in the brake gear, by means of the adjuster, and an entire new set of shoes applied. The slack should then be taken up, by turning casing 1 to the right, until the standing piston travel is from six to six and one-half inches, care being exercised to distribute the slack equally on both trucks by giving about the same angle to the dead levers. When the brake gear of a car, having a proper total leverage, is thus 68 AUTOMATIC SLACK ADJUSTER. equalized, the adjuster will maintain a constant piston travel until a full set of shoes has worn out, without any necessity of changing the position of the dead levers. The dead and live levers should each have such an inclination, when new shoes are applied to the wheels, that they shall have corresponding inclinations in the opposite direction when the shoes have become worn out. The proper inclination of the dead lever is established by securing the upper pin at a distance half the wearing thickness of the shoe nearer a vertical plane through the axle than that of the brake-beam clevis pin from the same plane, when new shoes are applied to the wheels. The proper inclination of the live lever is then secured by making the connecting rod or strut between the levers shorter, if outside hung-brakes, or longer, if inside hung-brakes, than the distance between the two brake-beam-clevis pins, by the wearing thickness of a shoe, the distance between the two brake-beam pins being measured when the shoes are all new and applied to the wheels. If the piston travel become too short, it will be found that either some of the slack in the brake rigging has been taken up by the hand brake, where the two work in oppo- sition, or the dead levers have been moved. If the piston travel is found to be too long, when the small pipe leading to the adjuster cylinder is free from ob- struction and the packing leather in the adjuster cylinder is free from leakage, it is more than probable that the slack has been taken up through an application and only partial release of the hand brake, and subsequent full release oc- curred only after the shoes had had time to wear more or less. The best results are obtained by the use of copper pipe from the brake cylinder to the adjuster cylinder, since this AUTOMATIC SLACK ADJUSTER. 6 9 pipe is more flexible and does not corrode. It should always be firmly secured. Every time the brake cylinder is cleaned and oiled, the slack-adjuster cylinder should obviously receive the same attention ; and, after each cleaning and oiling, a test of the brakes should also include one of the adjuster. PLATE 23. PORTJO BE,8f FROM, PRESSURE HEAD. METHOD OF DRILLING BRAKE CYLINDER FOR SLACK- ADJUSTER PIPE CONNECTION. PLATE 24. J3, U AIR-SIGNAL SYSTEM DETAILS. (70) The Train Air-Signal System* Plate 26 shows the general arrangement of the parts of the Train Air-Signal System upon a locomotive, tender and car ; a more detailed description of the arrangement will be unnecessary. This Plate is not intended to show the exact location of the parts, but is a diagrammatic illus- tration of the general arrangement only. Description of Parts. The Improved Reducing Valve. Fig. 4, Plate 24, shows the Improved Reducing Valve. An air pressure of 40 pounds should be carried in the signal system, and it is the function of this valve to reduce the main- reservoir pressure to this standard for use in the signal pipe. 7 and 10 are the reducing-valve piston and stem, which are supported by the tension of spring 13 and lowered by the pressure in chamber C, when sufficient to overcome the tension of the spring ; 4 is the supply valve, which is moved from its seat by the stem of piston 7 and is seated by the tension of spring 6. The tension of spring 13 is so adjusted, by regu- lating nut 14, that an air pressure of 40 pounds in chamber C is required to depress piston 7. When the valve is in the position shown, air from the main reservoir enters through the pipe connected at A, and, as indicated by the arrows, flows through chamber C into the signal pipe con- nected at B. As soon as signal-pipe pressure reaches 40 pounds, the pressure in chamber C forces piston 7 down and allows valve 4 to seat. No more air can then enter the signal pipe until, through leakage or otherwise, the signal-pipe pressure becomes reduced so that spring 13 may raise piston 7 to unseat supply valve 4. (71) 72 TRAIN AIR- SIGNAL SYSTEM. The Old-Style Reducing Valve. In the Old-Style Reducing Valve (Plate 25), the ten- sion of spring 9, between cap 3 and diaphragm 7, forces supply valve 5 from its seat, whenever the air pressure act- ing upon diaphragm 7 is insufficient to compress the spring. The parts being in the positions shown in the cut, air from the main reservoir enters at Z, passes unseated valve 5 into chamber A below diaphragm 7, and discharges into the signal pipe at Y. When the pressure below dia- phragm 7 becomes sufficient to overcome the tension of regulating spring 9, diaphragm 7 is thereby raised, and valve 5 is seated by the tension of spring 10. A subse- quent reduction of signal-pipe pressure permits regulating spring 9 to again force diaphragm 7 down and unseat valve 5. The Signal Valve. In the Signal Valve (Fig. 1, Plate 24), the two com- partments A and B are separated by diaphragm 12, and diaphragm stem 10, secured thereto, extends through bushing 9, its end acting as a valve on seat 7 of cap nut 16, above passage e. Diaphragm stem 10 fits bushing 9 snugly for a short distance below its upper end, to where a per- ipheral groove is cut in the stem, below which it is milled in triangular form. The air enters the signal valve at Y and flows through port d, charging chamber A, and through passage c, passing stem 10, into chamber B. The whole being charged, a sudden reduction of pressure in the signal pipe reduces the pressure in chamber A, above dia- phragm 12, and the unreduced pressure in chamber B, act- ing upon its lower surface, forces diaphragm 12 upward and momentarily permits air to escape from the signal pipe and chamber B to the whistle, through a pipe attached at X. PLATE 25. * re Signal p/pe. TO MAW RESERVOIR. OLD-STYLE REDUCING VALVE. (73) ^4 TRAIN AIR-SIGNAL SYSTEM. The resulting blast of the small signal whistle (Fig. 3), located in the locomotive cab, is a signal to the engineer. The same sudden reduction of pressure also operates upon the reducing valve to cause air from the main reservoir to flow into the signal pipe and restore the pressure. Equilib- rium of pressure quickly occurs in chambers A and B, and the valve at the end of stem 10 returns to its seat. The Car Discharge Valve. The Car Discharge Valve (Fig. 2) is usually located outside of the car, above the door and opposite the opening through which the signal cord passes. A branch pipe extends from the main signal pipe to the Car Discharge Valve, and in this pipe is placed a one-half-inch cock, by means of which the valve on the car may be cut out when desired. Each pull upon the signal cord causes lever 5 to open valve 3, permitting a small quantity of air to escape from the signal pipe, and thereby causes a signal to be trans- mitted to the engineer, through the operation of the Signal Valve and Whistle, as previously described. General. Inasmuch as any discharge of air from the signal pipe causes the air whistle to sound on the locomotive, it is obvious that all air-signal pipes should be perfectly tight, so that signals may not be incorrect and may not occur when not intended. An interval of three seconds, in which to assure re- charging of the signal pipe, should be permitted to elapse between successive discharges of air from the car discharge valve. Upon trains of exceptional length, this time inter- val should be slightly increased. £-« TRAIN AIR-SIGNAL SYSTEM. TRAIN AIR-SIGNAL SYSTEM. 75 Wherever possible, the Reducing Valve and Signal Valve should be so located inside the cab that they will be protected from both cold and excessive heat. The signal-pipe air strainer upon the car should always be located as indicated upon Plate 26. A special form of air-strainer is now provided for use between the main reservoir and the reducing valve upon locomotives. The High-Speed Brake* The High-Speed Brake, illustrated on Plate 27, is a modification of the Quick-Action Air Brake, through the addition of the appliances outlined in red. A further mod- ification is made in the standard equipment, by substituting a quick-action triple valve for the plain triple valve usually employed upon the tender, and also by the use of a special plain triple valve to operate the driver and truck brakes. The names, method of connecting, and the adjustment of the parts are indicated on this Plate, and the construction and operation of the parts, with the exception of the Automatic Reducing Valve, have been explained in other parts of this book. The locomotive equipment of Plate 27 may be changed from the Quick-Action to the High-Speed Brake by simply turning two handles — that of the reversing cock and that of the quarter-inch cut-out cock in the pipe leading to the 90-pound pump governor. When these handles are in the positions shown on Plate 27, the 70-pound feed valve and the 90-pound pump governor are in service, so that the locomotive is ready to operate the ordinary Quick- Action Brake ; 70 pounds pressure is carried in the train- pipe when the brake valve is in running position, and the pump will stop when main-reservoir pressure reaches 90 pounds. If the reversing-cock handle be turned to the opposite position and the handle of the quarter-inch cock in the 90- pound-governor pipe be turned at right angles to its present position, the no-pound feed valve and the high-pressure pump governor will become operative and, in the running position of the brake valve, no pounds trainpipe pressure and a main-reservoir pressure to correspond with the ad- justment of the high-pressure governor will result. (76) £ O CVi/A/flf/? OKI c 7"0 /T < > u Q W y < s o H (81) 82 AUTOMATIC REDUCING VALVE. Cars not equipped with the Automatic Reducing Valve should not be attached to trains employing the High-Speed Brake, unless the brake cylinders are equipped with the safety valve provided for temporary use in such cases. The Safety Valve (illustrated on Plate 31) has been es- pecially designed to prevent a higher than standard pres- sure in the brake cylinders of cars not equipped with the Automatic Reducing Valve ; it may be quickly screwed into the oiling hole of the brake-cylinder head, and re- moved when the cars are again placed in ordinary service. Fig. 3. 5ition of ports. ERGENCY STOP. PLATE 31. a_ 1/- pipe tiT'l tap SAFETY VALVE. High-Pressure Control, or Schedule U* The High-Pressure Control Equipment is illustrated on Plate 32. It consists of simple appliances, by means of which the engineer can change the trainpipe and main- reservoir pressures from one predetermined standard to another, at will. This equipment is particularly adapted for use upon heavy grades, where " empties" are hauled up the grades and " loads " down, a pressure of 70 pounds being carried in the trainpipe when the cars are empty, but increased to 90 pounds when the cars are loaded. If the high pressure were carried with empty cars in the train, flat wheels would be apt to result ; but, when the cars are loaded, the higher braking power is so moderate a proportion of the total weight of the car and its contents that danger of wheel sliding is practically eliminated. The following table illustrates the different relative conditions, the figures being based upon a braking power of 70 percent, of the light weight of an ordinary 60,000-pound freight car, when a 70-pound trainpipe pressure is employed. In an emergency application of the brakes, the brake-cylin- der pressure is, of course, 60 pounds ; while, in a service application, the cylinder pressure is 50 pounds. KIND OF EMPTY OR BRAKING POWER IN PER APPLICATION. LOADED. CENT. OF TOTAL WEIGHT. Emergency Empty 70 a Loaded 22.1 tO 23.8 Service Empty 58.3 n Loaded 18.4 to 20 (84 ) HIGH-PRESSURE CONTROL, OR SCHEDULE U. 85 This table shows that the braking power is so small a proportion of the weight, when a car is loaded to its full capacity, that, even with a trainpipe pressure of 90 pounds, there is ordinarily no danger of sliding wheels. The differences between the Schedule U and High- Speed Brake Equipments are as follows : No additional parts are used on the cars with Schedule U ; Safety Valves take the place of the Automatic Reducing Valves in the locomotive and tender equipment ; Plain Triple Valves are used with both locomotive and tender brakes, and the piping to the Duplex Pump Governor is changed in one particular. The description of the High-Speed Brake Equipment upon the locomotive applies also to that of the locomotive equipment with the High-Pressure Control Apparatus, ex- cept the effect produced by the change in the governor piping, which is as follows : The reversing-cock handle being in the position shown in the diagram, causing the 70- pound feed valve and the 90-pound pump governor to be operative, the entire brake apparatus will operate in the usual manner, except under one condition. Where the pump governor is piped to the brake valve in the usual manner, it cuts off the steam supply to the pump when main-reservoir pressure has attained its ordinary maximum limit ; but when it is piped to the chamber in the feed-valve bracket, as is the case when Schedule U is used, main- reservoir pressure is cut off from action upon the diaphragm of the pump governor when the brake-valve handle is in the Lap, Service Application or Emergency Application Position. It thus occurs that, although the main -reservoir pressure is operative upon the 90-pound pump-governor diaphragm in the Running Position of the brake-valve, it is inoperative when the brakes have been applied and 86 HIGH-PRESSURE CONTROL, OR SCHEDULE tf. the valve handle has been returned to "lap,'* and main- reservoir pressure may then be pumped up to the limit established by the high-pressure governor diaphragm. This high main-reservoir pressure insures a prompt release and quick recharging of the brakes upon a long train, and the pump has to operate against the high pressure only during the time that the brakes are applied. Whenever loaded trains are to descend long, heavy grades, the handle of the reversing cock is turned to its opposite position, thus cutting out the 90-pound governor and the low-pressure feed valve. The trainpipe pressure is then controlled by the high-pressure feed valve. The brakes are then operated in the usual manner ; but, as the trainpipe and auxiliary-reservoir pressures are now 90 pounds, a much more powerful brake application is avail- able if desired. The purpose of the safety valves connected with the driver and tender brake cylinders is to prevent the accu- mulation of a higher cylinder pressure than 50 pounds. Description of the parts of the High-Pressure Control Apparatus, not described under this caption, will be found in other parts of this book. When carrying a trainpipe pressure of 90 pounds upon freight trains, a trainpipe reduction of about 25 pounds will be necessary to equalize auxiliary-reservoir and brake- cylinder pressures, with the customary average piston travel. T/?VCA- G/?AX£ ttS£KVO/K VALVC SI.ACK s40*jvs-r£*9 £T/V r W where a is the known distance. It is to be understood, of course, that if a force is operative at any one of the three pins, forces must also be operative at both of the other two pins ; but the force acting at the fulcrum pin does not require consideration in (101) I02 LEVERAGE. determining the relation between the forces acting at the other two pins. The force at any one of the three pins may, in such calculations, be regarded as the applied force, and that at either of the other two may be treated as the delivered force, the remaining pin becoming the fulcrum in that case. There thus appear to be three different sets of condi- tions, depending upon the relative position of the fulcrum pin ; but the same rules and formulae apply to each. The three cases are illustrated, as applied to the truck brake lever, on Plate 34. In each of the three cases, the formulae for determining the applied and delivered forces and their distances from the fulcrum pin are given, and it will be observed that the formulae are precisely the same in all three cases, except as affected by the following considerations. It sometimes occurs that, when the middle pin is the fulcrum pin, the applied and delivered forces at the end pins are given, but the only distance known is that between the end pins. In that case, neither distance a nor b y but only their sum, is known. In such a case, it is neces- sary to proceed as follows : Let the length of the lever — or the distance between the end pins — be represented by /. Then, since the middle pin is the fulcrum, /=#+ b, so that a = l — b and b = l — a. Substituting these values of - ■ . - . IVX b A . FXa a and b in the equations a = — ^ — and b= — uz~* re ~ .1 • • , j, WX I Jz FX / spectively, it is found that a = ^ , TT _ and = = , Tr . . F+W F+W The values of a and b having been obtained by these formulae, the correctness of the computations may always be checked, since the sum of the computed values of a and b must equal /. PLATE 34. or a =H— *J_ F+W or h= F * l W F+W FULCRUM BETWEEN APPLIED AND DELIVERED FORCES. W Fxa a g-ELfe or g = W*d F W-F b = Z*JL or b= Fxd W W-F DELIVERED FORCE BETWEEN FULCRUM AND APPLIED FORCE. Vff =. Fxg b F a~ F*d h -^ or &- APPLIED FORCE BETWEEN FULCRUM AND DELIVERED FORCE* (103) 104 LEVERAGE. It sometimes also may occur that both the applied force /^at one pin and the force IV that must be delivered at another pin are known, but the only additional informa- tion is the difference between the distances a and 6, the fulcrum being an end pin. Let d represent the difference between the distances a and b. Two cases arise. In one case, a is greater than b by d inches. Then a = b + d and b = a — d. Substituting these values of a and b in the IV X b , , F*a equations a = — ^ — and o = , respectively, it will W* d Fx d ^ 1 t be found that a = ~ttj ^ and b = — . I he check IV— F IV — F is that the calculated value of a must be equal to the sum of d and the calculated value of b. In the other case, a is less than b by d inches. Then a = b — d and b = a -f d; and, in a similar manner, it is WX d Jz F X d _ . - . , iound that a = — Ttt and <7 = -= — ==; 1 he check is that F— IV r — W the calculated value of a must be equal to the calculated value of b less d inches. The force acting at the middle pin of a straight lever is always equal to the sum of the forces acting at the other two pins, and this fact furnishes the means of checking the correctness of calculated forces. It is of the utmost importance that the same units of force and distance be preserved throughout calculations, all forces being preferably expressed in pounds and all distances in inches. It is equally important to remember that each reference to the distance between pins invariably means the distance from center to center of pins or of pin holes. The following practical example will illustrate the method of employing the formulae above given. It is re- LEVERAGE. I05 quired to apply the air brake to a freight car weighing 34,286 pounds. The general construction of the brake gear is to be as shown on Plate 35. The live truck lever is 30 inches long, is secured to the brake beam at the lower end and inclines at such an angle (40 degrees from the vertical) that the upper end is 19 inches from the center line of the car. The middle hole in the lever, for securing the strut connection to the dead lever, is 6 inches from the lower hole, and is consequently 24 inches from the upper hole. As the car weighs 34,286 pounds and the proper emergency braking power is 70 per cent, of the light weight, the pressure from the four brake beams upon the wheels must be 24,000 pounds, or 6,000 pounds per beam. The delivered force ( TV) at the lower end of the live lever must therefore be 6,000 pounds ; the middle pin is the fulcrum ; the distance (£) from the fulcrum to the delivered force is 6 inches, and the distance (a) from the fulcrum to the applied force (F) at the upper pin is 24 inches. Sub- stituting these values of W y a and b in the formula WX b F = , the force that must be applied at the upper • U +U A ' 77 6 >°°° X 6 pin by the upper rod is r r= = 1,500 pounds. To find the force delivered by the live lever, through the strut connection, to the dead lever, the lower pin be- comes the fulcrum, 1,500 pounds is the applied force (F) at the upper pin, 30 inches (a) from the fulcrum, and the delivered force ( IV) is 6 inches (b) from the fulcrum. TU , TJ/ FX a 1,500x3° 1 ^, I herefore, W = — = = 7 , 500 pounds. The correctness of this result is checked by adding the forces (1,500 pounds and 6,000 pounds) acting at the upper and lower pins, respectively, which must equal the force at the middle pin. CO T3 CI 03 03 . en 03 4-> c O g o '-3 u G u CJ CD Oh "a a, v s t^ < -5 .2 u cd *-m O K-* (J C/5 a CD ^ T5 G a; ^§: G O s w H< Oh 8 .S fr .s 03 G «£ cn u & cn CD •£ e u in o M— 1 J5 W 10 £ £ O CO o cn W Ch o3 n 8 H bJO G .H < • — '-3 .2 £ H-3 Ph cd Ih plicat 11 Se: • •» ^ Cu r ^ en T3 a, vO 00 v & -51 Ifru CN in — • — T? H 3 en CO a fr. CD H_l (J oJ o u < .5 o «-f-i u en cd