LIBRARY 
 
 UNIVERSITY OP 
 V CALIFORNIA 
 
THE COMPOUND LOCOMOTIVE 
 
 SUPPLEMENT TO 
 
 THE SCIENCE OF RAILffAIS. 
 
 BY 
 
 MARSHALL M. KIRKMAN. 
 
 THIS SUPPLEMENT IS RESPECTFULLY PRESENTED BY THE WORLD 
 RAILWAY PUBLISHING COMPANY TO SUBSCRIBERS TO 
 THE EIGHTH EDITION OF "THE SCIENCE OF RAIL- 
 WAYS" AND IS DESIGNED TO FORM A PART 
 OF THE "ENGINEERS' AND FIREMEN'S 
 MANUAL," VOLUME XII. 
 
 EIGHTH EDITION. 
 
 NEW YORK AND CHICAGO: 
 
 THE WORLD RAILWAY PUBLISHING COMPANY. 
 1899 
 
LOAN STACK 
 
 COPYRIGHT Br 
 
 THE WORLD RAILWAY PUBLISHING COMPANY, 
 
 The Regan Printing House, Chicago. 
 
CHAPTER T. 
 
 ENGINEERS' AND FIREMEN'S MANUAL, CONTINUED- 
 COMPOUND LOCOMOTIVES INTRODUCTORY. 
 
 NOTE In regard to the merits of the compound cylinder as 
 compared with the single-expansion, I do not desire nor profess 
 to express any opinion. I merely wish to describe the compound 
 cylinder in what follows, and, if in some places preference seems 
 to be expressed, it is the claim of builders and not mine. Those 
 who use locomotives must themselves be the judges of the re- 
 spective merits of single-expansion and compound cylinders and 
 of the particular pattern they want. 
 
 January, 1899. M. M. K. 
 
 In view of the fact that the Compound Loco- 
 motive is of comparatively recent introduction as 
 compared with the single-expansion cylinder, its 
 construction and working are less understood by 
 those connected with the equipment department 
 of railroads. These particulars I have, for that 
 reason, thought it best to embody here in con- 
 nection with the "ENGINEERS' AND FIREMEN'S 
 MANUAL." More and more attention is being 
 given to the expansive use of steam in connection 
 with the locomotive. It is claimed not to be un- 
 reasonable in view of the triple and the quadruple 
 expansion of steam (expansion in three and four 
 cylinders) in the most approved stationary and 
 marine engines that it should be possible to de- 
 vise practical means of obtaining double expan- 
 
 (3) 
 
 865 
 
4 tiNGINEEffl* AND FIREMEN'S MANUAL. 
 
 sion, at least, in a locomotive. Because of the 
 more or less general introduction of compound 
 cylinders, some account of the working of the com- 
 pound locomotive is becoming every day more 
 and more necessary to those connected with the 
 machinery and equipment of railroads. Indeed, 
 practical familiarity with the working of com- 
 pound engines may be said to have become, in a 
 measure, a necessary part of the knowledge of 
 every engineer and fireman, for the reason that 
 their duties may at anytime, through promotion 
 or otherwise, take them to roads where some 
 form of compound locomotive is extensively used. 
 Moreover, it is well that their attention be espe- 
 cially directed to the subject in order that it may 
 have the consideration and scrutiny at their 
 hands which its growing importance justifies and 
 their practical knowledge is likely to render so 
 valuable. 
 
 It is not surprising, inasmuch as the opinions 
 of engineers and firemen respecting the opera- 
 tion of simple engines differ so widely, that there 
 should be much controversy among them in re- 
 gard to the operation of compound locomotives. 
 Experience on the part of those operating the 
 compound locomotive will tend to its better 
 service and consequently greater development. 
 Many prejudices against it are due to lack of ac- 
 quaintance with its operation. This is true of 
 every new thing. Especially is it true in the 
 case of compounds where a railway has few loco- 
 motives of this kind. The feeling is but natural, 
 if we remember, as we should, that in the handling 
 
COMPOUND LOCOMOTIVES. 5 
 
 of their engine the reputation of the engineer 
 and fireman is at stake. The opportunity af- 
 forded them for handling and studying any odd 
 engine, compound or otherwise, is necessarily 
 limited. Moreover, in the operation of such lo- 
 comotive, it is possible they may be impressed 
 with the unhandy, because unusual, cab arrange- 
 ments. Naturally, they are filled with appre- 
 hension, lest some accident might occur and 
 they be found ignorant of what should be done 
 to temporarily repair the engine and bring it in. 
 If a considerable number of the locomotives of a 
 railroad are compounds of similar class, the men 
 handling them become accustomed to their opera- 
 tion and this fear disappears. It is with a view 
 to the practical usefulness these pages may have 
 for engineers, firemen, and others interested in 
 the operation of compounds, that the descrip- 
 tions herein are elaborated to the extent they are. 
 The plan followed with each class of compound 
 locomotives is, first, to give a general description 
 of its operation, succeeded by a detailed descrip- 
 tion of its technical parts. This is done that the 
 reader may, in the first instance, if he desires, 
 learn of the general arrangement of each class 
 without the details, and afterwards, at his leisure, 
 he may apply himself to the particular class or 
 classes that most interest him. Following the 
 description of each class of compounds will be 
 found, in catechetical form, information relating 
 to its operation in case of any ordinary derange- 
 ment of its parts when the methods of procedure 
 will differ from those in case of similar accidents 
 
6 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 to simple locomotives, as outlined in the manual. 
 It is said that reforms must pass through 
 three stages: ridicule, argument, and adoption. 
 The compound has been subjected to the first 
 and second of these epochs, and it may be as- 
 sumed to have reached the last stage mentioned. 
 Like every part of a railroad, it is still in a state of 
 evolution. I know of no preference in regard to 
 compounds that is proper to express here. The 
 order of description has, therefore, no signifi- 
 cance. In the description of the various types I 
 have endeavored to eliminate all matter that 
 does not pertain directly to the practical appli- 
 cation of the principle of compounding, as de- 
 scriptions relating to other parts of the locomo- 
 tive are to be found elsewhere in "THE SCIENCE 
 OF RAILWAYS." In relation to the descriptions 
 of the compound, I wish to say that I am in- 
 debted in a marked manner to Mr. E. W. Pratt, 
 whose familiarity with the construction and 
 working of locomotives and the appliances of the 
 latter makes him an authority of the highest or- 
 der in regard to all such matters. I am in- 
 debted to him in many other ways and it affords 
 me much gratification to be able to acknowledge 
 it thus conspicuously. 
 
CHAPTEE II. 
 ENGINEERS' AND FIREMEN'S MANUAL COMPOUND 
 
 LOCOMOTIVES GENERAL DESCRIPTION COM- 
 PARISON WITH SIMPLE LOCOMOTIVES. 
 
 A compound locomotive is one in which the 
 exhaust from one or more cylinders is passed 
 into one or more other cylinders and made to do 
 more work by further expansion before it is al- 
 lowed to escape to the atmosphere. In stationary 
 and marine service the principle of compounding 
 has long since passed its experimental stage and, 
 following the replacement of the single-expansion 
 engine by the double-expansion type, came the 
 era of high boiler pressures with triple and even 
 quadruple-expansion engines in marine service. 
 It was long thought by many, and is still held 
 by some, that, although compounding of steam 
 in marine and stationary engines was a great 
 economy due to the use of the condenser,* on 
 locomotives where condensers were impractic- 
 able, the compound locomotive would not be able 
 to gain sufficient advantage over the simple 
 engine to warrant their general use. 
 
 Without any attempt to pass judgment upon 
 the relative value of the points put forward for 
 and against compound locomotives, I will out- 
 
 *A condenser is a chamber into which the final exhaust of an 
 engine takes place and in which the steam is cooled and con- 
 densed, either by a jet of water or by contact with sheets or 
 tubes having cold water circulation on their opposite sides. 
 These two forms of condensers are termed "jet condenser" and 
 "surface condenser," respectively. 
 
 (7) 
 
8 EXGIXEERS' AXD FIREMEN'S MANUAL. 
 
 line some of the claims made by their advocates 
 and also some of the practical objections met 
 with in their use, many of which objections 
 have been largely overcome- in the later 
 designs. 
 
 It should be remembered that the locomotive 
 is not a steam engine merely, but consists of a 
 boiler as well, and must also carry water and fuel 
 for its own demands. 
 
 The first advantage of the compound over the 
 simple locomotive comes from its greater economy 
 in fuel, resulting primarily from the saving in 
 steam. There is, however, a secondary saving, pro- 
 duced by the less violent effect of the exhaust upon 
 the fire and also the economical use of high boiler 
 pressures in compound engines. 
 
 Experiments have shown that high boiler pres- 
 sures, say above 180 pounds, which have been 
 found very economical (especially in the space 
 occupied per horse power developed) in station- 
 ary and marine engines, are not a source of econ- 
 omy with the type of single-expansion locomotives 
 in use in this country, due to the extreme ranges 
 of temperature within a single cylinder and the 
 consequent condensation. Also, locomotive cylin- 
 ders and their steam ports are not well protected, 
 and compounding the cylinders renders the varia- 
 tions of temperature in each cylinder less wide, 
 and thus makes practicable the use of higher pres- 
 sure. With the use of steel in place of iron for 
 boiler construction, and also on account of the 
 excellent care and inspection given all locomo- 
 tive boilers, there is no material increase of first 
 
COMPOUND LOCOMOTIVES. 9 
 
 cost or for maintenance of high-pressure boilers. 
 In simple locomotives the exhaust produces 
 such a violent draft upon the fire that great 
 quantities of unconsumed fuel are drawn from 
 the fire-box and thrown from the stack. This is 
 not alone a waste of fuel, but cinders entering 
 the open car windows are a source of great an- 
 noyance to passengers, while, before the use of 
 the compound locomotive in the service of subur- 
 ban railways, the noise of the exhaust had to be 
 overcome by means of mufflers, which became 
 quickly choked up and produced a high back- 
 pressure on the pistons, resulting in the loss of 
 from 15 to 20 per cent, of the power. 
 
 The throwing of sparks from the stack is not 
 only a source of annoyance, but frequently re- 
 sults in heavy losses from damage by fire in tim- 
 ber and agricultural districts, and this is largely, 
 if not entirely, overcome by the compound 
 locomotive. 
 
 The heating surfaces of any given boiler absorb 
 heat from the fire and deliver it to the water at 
 a certain rate. If the rate at which the products 
 of combustion are carried away exceeds this rate 
 of absorption, there will be a continual waste 
 that can only be overcome by reducing the veloc- 
 ity of the products of combustion. In the com- 
 pound locomotive this is effected by the milder 
 exhaust. It has been clearly demonstrated by 
 experiment, that a milder exhaust and conse- 
 quently a slower rate of combustion produces a 
 greater evaporation of water per pound of fuel. 
 
 The milder exhaust is, of course, the result of a 
 
10 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 lower back-pressure and thereby permits a greater 
 effective power on the piston. 
 
 There is also found to be considerable reduction 
 in cylinder condensation, owing to the relatively 
 small variation of temperatures in each cylinder 
 as compared with single-expansion engines. In 
 any engine the walls of the cylinder, one cylinder- 
 head, and one side of the piston are cooled to the 
 temperature of the exhaust steam during each 
 stroke, and the live steam, again entering, must 
 
 Fig. 100. 
 
 4 StroKt .&n>Ke - $StroKe fuUStrakt 
 
 I 
 _;2o 
 
 
 LENGTH or STROKE 
 
 reheat them to its own temperature, thus con- 
 densing and requiring additional steam to flow in 
 and take its place. In the compound this total 
 range of temperature is divided between the high 
 and the low-pressure cylinders, and thus the vari- 
 ation and consequent condensation in each cylin- 
 der is less. 
 
 The saving of steam results in the saving of 
 
COMPOUND LOCOMOTIVE*. 11 
 
 both water and fuel. The economy in fuel can 
 be directly reduced to dollars and cents, while 
 that resulting from the saving of water is more 
 indirect. In bad water districts, the reduction 
 of from 15 to 20 per cent, in the amount of water 
 used, necessitates less frequent washings-out of 
 the boiler and must result in greater life and 
 diminished repairs to boiler and flues. Moreover, 
 as its carrying capacity of water limits the dis- 
 tance that a locomotive can run without stopping 
 (or slowing up, where track-tanks are used), it is 
 evident that the compound locomotive would have 
 an advantage in this respect. Fig. 100, besides 
 showing the most economical point of cut-off for 
 simple and compound engines, as far as the use 
 of water is concerned, clearly shows the relatively 
 smaller amount of water used by the compound 
 per indicated horse power. 
 
 No locomotive can haul more than its adhesion 
 to the rails will permit, and hence the tractive 
 power of an engine is based upon whatever the 
 adhesion to the rails may be. This is determined 
 by practical experiment. With a fairly dry rail, 
 a turning force of more than one-fifth, or 20 per 
 cent., of the weight of the drivers on the rails, 
 will cause the wheels to slip; a perfectly dry rail 
 will permit of a tractive power of about one- 
 fourth, or 25 per cent., of the weight on the 
 drivers; a well sanded dry rail will allow one- 
 third, or 33^ per cent., while a bad frosty rail 
 will permit less than half this last amount. 
 Where all the driving wheels are connected, it 
 matters not, -of course, whether this force is ap- 
 
12 ENGINEERS' AND FIREMEN\* MANUAL. 
 
 plied by one or many cylinders, but, if the power 
 is not uniformly distributed throughout the revo- 
 lution and becomes sufficiently excessive at any 
 one point to cause the wheels to slip, a very 
 much less power will thereafter keep them slip- 
 ping. It is a well known fact that adhesion, and 
 consequently the tractive power of a locomotive, 
 is verv much reduced after the wheels begin to 
 slip.*" 
 
 It is claimed for the compound, that, as the 
 average cut-off is later in both cylinders than for 
 simple engines, the turning power is more uni- 
 form throughout the revolution, and hence heavier 
 trains can be hauled than with the single-expan- 
 sion engine. Then, too, while it would be un- 
 economical at other times to design a simple 
 engine with cylinders sufficiently large to develop 
 so high a tractive power as 33^ per cent, at slow 
 speeds, this can be done with compound loco- 
 motives of the "convertible" type without loss 
 in economy under ordinary speeds of service, 
 when working compound. 
 
 A saving of oil has been one of the minor econ- 
 omies claimed to be incidental to the use of com- 
 pound locomotives. It is generally thought that 
 from six to ten drops of valve oil per minute are 
 required to be supplied with the steam in order 
 to properly lubricate a valve and cylinder. This 
 
 *Every engineer knows this and puts his knowledge into prac- 
 tice when on a very slippery rail by opening the throttle very 
 slightly and leaving the valve in full gear, thus distributing the 
 pressure more uniformly throughout the stroke than would be 
 the case with a shorter cut-off, 
 
COMPOUND LOCOMOTI VES. 1 3 
 
 oil is supplied to the high-pressure cylinder only, 
 and hence, in the two-cylinder class of com- 
 pounds, a saving has been effected in many cases. 
 
 Comparative tests of greater or less duration 
 have been made by various railways, between 
 compound and simple locomotives of otherwise 
 similar construction, and the results obtained by 
 the different experimenters are widely at vari- 
 ance. In general, it may be said that the re- 
 ported saving in fuel with the compound is about 
 ten per cent, in fast passenger and 20 per cent, 
 in heavy freight service, although figures double 
 the latter have frequently been given.* 
 
 Later designs of compound locomotives, arranged 
 to be worked simple at the will of the engineer, will 
 temporarily pull a heavier train than a simple 
 engine of otherwise like design. When it is con- 
 sidered that the ruling grade on a division is the 
 governing factor for the maximum rating of 
 through trains over the whole division, it will be 
 seen that a locomotive capable of enough greater 
 power to haul an additional car or two up that 
 grade, produces more economical service for the 
 whole division. 
 
 Leaky valves and cylinder packing are less 
 wasteful in a compound than in a simple engine. 
 Steam leaking by the valve or packing of the 
 high-pressure cylinder is still worked expansively 
 
 *Fast freight service will more nearly compare with express 
 passenger service and the saving will be less than in heavy slow 
 freight service, on account of the simple engine using steam 
 more expansively in the former service than in the latter. This 
 is more fully brought out elsewhere. 
 
14 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 in the low-pressure cylinder. Then, too, the dif- 
 ference of pressure between the two sides of the 
 valves and pistons is less than for simple engines, 
 and the wear should be consequently less. 
 
 On the other hand many serious practical ob- 
 jections have been raised. The large cylinders 
 greatly increased the weight of the reciprocating 
 parts.* This must be followed by heavier coun- 
 ter-balancef weights and their accompanying 
 evils. % Also larger ports and consequently larger 
 valves must be provided for the large cylinders. 
 Inasmuch as considerable difficulty was formerly 
 experienced in obtaining admission and exhaust 
 ports of sufficient size for the cylinders of 
 large high-speed single-expansion engines, it is 
 not remarkable that there should have been con- 
 siderable trouble experienced from this source in 
 designing ports for the much larger cylinders of 
 the compound locomotive. 
 
 In connection with these last two points, the 
 weight of reciprocating parts and the port re- 
 
 *By the reciprocating parts is meant those parts that have a 
 forward and back (or reciprocating) motion. This includes the 
 pistons and piston-rods, the cross-heads and a certain part of 
 the main rods. 
 
 fThe counter-balance is the balance weight placed in the 
 wheel at a point opposite the crank pin. (See No. 240, Plate I.) 
 
 JThe counter-balance weights act at all points of the revolu- 
 tion, having an outward or centrifugal tendency from the center 
 of the wheel that is great at high speeds, and is only counter- 
 acted when the engine is passing the front and back centers. At 
 other points it produces an upward tendency upon the engine 
 when moving up and a downward blow upon the rails when 
 moving down. 
 
COMPOUND LOCOMOTIVES, 1 5 
 
 quirements, let us see for one moment what the 
 requirements for high speed are. Take an engine 
 with a live foot driving wheel and a twenty-four 
 inch stroke, traveling at the not unusual rate of 
 a mile a minute. This requires 386 revolutions 
 per minute, and means that the piston starts and 
 stops 672 times, and with all its stopping and 
 starting travels 1844 feet per minute. At mid- 
 stroke the piston speed is about 35 feet per second 
 or 24 miles per hour. To the average railway 
 man high speeds are so common that I can think 
 of no better way to show the full meaning of 
 these figures than to compare them with those of 
 a falling body acted upon by gravity. A falling 
 body at the end of the first second is traveling at 
 the rate of 32 feet per second, or about 22 miles 
 per hour, and in gaining this speed the body has 
 fallen some 16 feet, through which distance the 
 continued action of gravity has produced this not 
 inconsiderable acceleration, while in the case of 
 the piston of the locomotive in question, the still 
 greater speed of 24 miles per hour must not only 
 be attained by the time the piston has reached 
 the middle of its stroke, or in one foot, but also 
 it must be exerting great additional propelling 
 power on the crank pins. The steam in front of 
 this rapidly moving piston must be exhausted 
 freely or there would be no effective power to 
 maintain the speed. Where the reciprocating parts 
 weigh nearly a thousand pounds, it will be seen 
 what enormous power is required to stop and 
 start them without jar or shock to the loco- 
 motive, and also the size of ports required to 
 
16 EXGIXEEU*' AX1) FUIEMEX't MAXL'AL. 
 
 freely exhaust the pressure ahead of and freely 
 supply steam behind the very large pistons of 
 compound locomotives. With any of the several 
 types of valve gear used in locomotive practice 
 to-day, it goes without saying that no compound 
 can be relatively so efficient, in comparison with 
 single-expansion engines, in express passenger as 
 in freight service, for the reasons hereinbefore 
 described. When many single-expansion loco- 
 motives with moderately large ports require a ve- 
 locity of steam through their ports of over 1,000 
 feet per second, it can better be imagined than 
 told what the port requirements are for the large 
 low-pressure cylinder on a compound. It is gen- 
 erally considered that for express passenger serv- 
 ice the low-pressure cylinders should not be so 
 large in proportion to the high-pressure cylinders 
 as for freight service. 
 
 Many of the earlier compounds in this country 
 suffered in comparative tests with simple engines 
 of otherwise similar design, by having cylinders 
 of too small a size to do the same work as the 
 simple engine. While they did their work with 
 economy, they would not haul the heavy trains 
 of the simple engines, and their supposed capacity 
 had to be reduced, to the annoyance of those en- 
 gaged in the operating of trains. Since then, with 
 the advent of larger cylinders and the "convert- 
 ible" class of compounds, the conditions have 
 become altered. 
 
 With any locomotive, when steam is shut off, 
 as in running down grade, the pistons act as air 
 compressors, causing thumping, rough riding, and 
 
COMPOUND LOCOMOTI VES. 1 7 
 
 cooling of the cylinders, as well as a strong draft 
 in the stack at a time when no steam and little 
 draft are required, and thus produce a waste of 
 fuel. The large low-pressure cylinders of the 
 compound have greatly magnified this evil, and 
 several builders have overcome it by the use of 
 automatic valves on the low-pressure cylinder, by 
 which the two sides of the low-pressure piston are 
 connected whenever the locomotive is drifting. 
 
 After closing the throttle, an engine working- 
 compound will make several strokes before all 
 steam is finally exhausted. This delay in clear- 
 ing the cylinders of steam, placed compound 
 locomotives to considerable disadvantage in 
 switching or like service; also, in such service, 
 accustomed to gauge the speed by the exhaust 
 of the engine, trainmen were often deceived by 
 the less frequent exhaust of the two-cylinder com- 
 pound. The employment of the separate high- 
 pressure exhaust, whereby the engine can be run 
 simple at the will of the engineer, it appears, 
 has overcome these objections from an operating- 
 standpoint. 
 
 Many of the earlier forms of intercepting valves 
 were of the poppet type and hammered badly in 
 opening or closing. It will be noticed that these 
 valves in the later designs are of the piston type 
 and are almost invariably cushioned by dash-pots 
 connected thereto, or some other equally effective 
 means. 
 
 It is also claimed that the breakage and loosen- 
 ing of the large low-pressure cylinders have been 
 considerably done away with by the use of proper 
 
18 ENGINEER^ AXD FIREMEN'S VAXTAL. 
 
 reducing valves and a better attachment of cylin- 
 ders to the frame, the use of double front rails for 
 the latter being particularly noticeable in modern 
 construction of large locomotives. 
 
 Thus it is that improvements in design and con- 
 struction are continually taking place, and the 
 upholders of the great principle of compounding 
 will certainly witness their more extensive adapta- 
 tion to all classes of service. 
 
CHAPTER III. 
 
 ENGINEERS' AND FIREMEN'S MANUAL CLASSES OF 
 COMPOUND LOCOMOTIVES AND THEIR GENERAL 
 
 CONSTRUCTION. 
 
 There are many classes of compound locomo- 
 tives in use. First, the strictly plain compound, 
 where no live steam is admitted to the low-pres- 
 sure cylinder, even in starting. The Webb three- 
 cylinder compounds (with cylinders arranged as 
 outlined in Fig. 106,) which are usually with- 
 out connecting rods the two high-pressure cylin- 
 ders turning the rear pair of driving wheels by 
 
 two outside cranks while 
 the low-pressure cylinder 
 turns the forward drivers 
 by means of an inside 
 crank belong to this 
 class and are used in con- 
 siderable numbers on the 
 London & North-Western 
 of England. They are not 
 powerful in starting, as 
 the driving wheels acted 
 
 upon by the high-pressure cylinders must turn, 
 either by slipping or moving the train, before 
 steam enters the low-pressure cylinder. 
 
 Second, automatic compounds those using live 
 steam in the low-pressure cylinder in starting 
 only, automatically changing to compound with 
 the first stroke, and thereafter cannot be run ex- 
 cept as compounds. 
 
 (19) 
 
20 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 The third class can be run simple or compound 
 at any time at the will of the engineer and will 
 be termed convertible compounds. 
 
 Each of these principal classes may have two, 
 three, or four cylinders. The two-cylinder or "cross- 
 compound" always has an intermediate recepta- 
 cle, called a receiver,* between the high and low- 
 pressure cylinders, while 
 the four - cylinder en- 
 gines may or may not 
 have receivers those 
 with both pistons at- 
 tached to the same 
 crosshead generally 
 have not. The three 
 systems of four-cylinder 
 compounds used in this 
 country are the Baldwin 
 (Vauclain), the Brooks 
 (Player), and the John- 
 stone. Of these, the Brooks has receivers, while 
 the remaining two are of the continuous expan- 
 sionf type and have no receivers. % 
 
 *The receiver is for the purpose of receiving the exhaust from 
 the high-pressure cylinder and holding it until the engine gets 
 to the point in the revolution where it is admitted against the 
 low-pressure piston. Incidentally, the receiver may act as a re- 
 heater, if located in the smoke-box, as is usually the practice. 
 
 fMeaning expansion without any pause or interruption as is 
 the case when a receiver is interposed between the high and the 
 low-pressure cylinders. 
 
 Jin Europe the Hurgarian State Railways employ four-cylin- 
 der tandem compounds with one receiver into which both 
 high-pressure cylinders exhaust and from which both low-pres- 
 sure cylinders receive their supply. 
 
CLASSES OF COMPOUND LOCOMOTIVES. 
 
 21 
 
 JFiq.103. 
 
 The arrangement of cylinders is quite varied, 
 as shown by the several skeleton cuts. There 
 may be two cylinders, one high-pressure and one 
 
 low-pressure, as outlined in 
 Figs. 101, 102 and 103; one 
 high and two low-pressure, 
 as in Figs. 104 and 105; two 
 high-pressure and one low 
 into which they both ex- 
 haust, as in Fig. 106; two 
 high, each exhausting in- 
 dependently into a low- 
 pressure cylinder on the 
 same side of the engine, 
 shown in Figs. 107, 108, 109 
 and 110; or two high ex- 
 hausting into a common receiver from which 
 both low-pressure cylinders draw their supply, as 
 in Figs. Ill and 112. Aside from the varied ar- 
 rangement of cylinders, 
 many of the European 
 designs employ three 
 and four cranks and use 
 no side rods. Some 
 French constructions, 
 retaining the use of side 
 rods, employ for the 
 high-pressure cylinders 
 two inside cranks on 
 one driving axle at an 
 angle with the low- 
 pressure cranks on a 
 second driving axle, the angle between the cranks 
 
22 
 
 ENGINEERS' AXD FIUKMKX'S UAXUAL. 
 
 being such as to give as large a turning power as 
 possible, for all portions of the revolution. 
 
 It is, perhaps, needless to say that the wide 
 variations in the service 
 of American locomotives 
 demand that they have a 
 large starting power at all 
 points of the stroke. To 
 obtain this starting power, 
 all the earlier designs 
 used a device called an in- 
 tercepting valve that, if 
 closed in starting, cut off 
 communication between 
 the receiver and the low- 
 -pressure cylinder and at 
 the same time admitted 
 live steam to the low-pressure side, but after the 
 first exhaust from the 
 high-pressure cylinder to 
 the receiver took place, 
 the pressure in the latter 
 automatically shoved open 
 the intercepting valve and 
 simultaneously shut off 
 the further supply of live 
 steam to the low-pressure 
 cylinder. Hence these en- 
 gines belong to the auto- 
 matic class of compounds. 
 Mr. Anatole Mallet, who 
 was the designer of the *"&' ' 
 
 first practical compound locomotives in Europe 
 
GLASSES OF COMPOUND LOCOMOTl \ 'EX. 
 
 in 1876, was also the first to devise a means by 
 which a compound could be worked as a simple 
 locomotive for any desired period at the will of 
 the engineer. This was accomplished by adding 
 a separate exhaust valve through which the ex- 
 haust from the high-pressure cylinder could escape 
 to the atmosphere without accumulating in the 
 receiver. This relieved all back pressure on the 
 high-pressure piston and admitted of greater power 
 at slow speed than was otherwise obtained.* 
 Many objections were raised to placing the 
 
 operation of the engine 
 either as a simple or as a 
 compound in the hands 
 of the engineer, and the 
 fear was freely expressed 
 that the average engineer 
 would run the locomotive 
 to its disadvantage in 
 simple position more than 
 enough to offset the sav- 
 ing when operated as a 
 compound. However, one 
 prominent railroad officer, 
 in placing the operation of the valves at the will 
 of the engineer, seemed to express the now settled 
 conviction of all, when he said: "To argue that an 
 
 *It should also be stated that not only were the automatic 
 compounds less powerful, at slow speeds after starting, than 
 simple engines, but, except in the case of four-cylinder engines 
 having one high and one low-pressure cylinder on the same side 
 they were practically helpless in case of a broken steam chest 
 on either side. The use of the separate exhaust valve has greatly 
 altered the conditions in these cases. 
 
24 EXGTXEEW AXJ) FIREMEX'X MA3TAL. 
 
 engineer is likely to work simple any longer than 
 absolutely necessary, is about the same as saying 
 that an engineer with the ordinary engine cannot 
 be trusted to pull the reverse lever up as soon as 
 possible." 
 
 Later practice interposed, within or near the 
 intercepting valve, a reducing valve, which is 
 used to admit live steam, at a reduced pressure 
 only, into the low-pressure cylinder when starting 
 or when working simple. This reduced the 
 
 abnormal shocks that were 
 produced when starting- 
 large compounds of earlier 
 design. The reducing 
 valve, the intercepting 
 valve, and the separate 
 
 /^ \eihaust valve were so 
 (-^^v) closely combined in many 
 cases and so dependent, 
 one upon the other, in 
 their operation, that it 
 'became the tendency 
 
 -F-ici.lUo. ., , 
 
 T among railway and me- 
 
 chanical men to refer to the w r hole mechanism 
 simply as the "intercepting valve." 
 
 While the limit to the size of the ordinary 
 locomotive may be considered to have been 
 reached when the largest practical boiler that can 
 be placed on a given gauge track has been attained, 
 the limit to the American two-cylinder, or cross- 
 compound, with outside cranks wall be the max- 
 imum width allowable for locomotives. However, 
 again Mr. Mallet, the father of the present era 
 
CLASSES OF COMPOUND LOCOMOTIVES. 
 
 25 
 
 of compound locomotives, has seemingly solved 
 the problem by dividing the low-pressure cylinder 
 into two cylinders, as shown in Fig. 105, of smaller 
 size attached to the same crosshead. With such 
 a construction it would appear that the boiler 
 would still be the limiting feature of the size of 
 the compound as well as the simple locomotive. 
 The proper cylinder ratio of compounds for all 
 varieties of service is still somewhat undeter- 
 mined. By the cylinder ratio is meant the propor- 
 tion between the volumes of the high and the 
 low-pressure cylinders, not including the clearance 
 
 spaces. In American practice where the length 
 of stroke is the same, the cylinder ratio would 
 be as the areas of the two pistons, and it can 
 readily be found by multiplying the diameter of 
 each cylinder by itself and comparing the two 
 products. For instance, to find the cylinder ra- 
 tio of an engine with a 20 inch high and a 30 
 inch low-pressure cylinder, multiply 20x20 equals 
 400; 30x30 equals 900; 400 goes in 900 two and 
 one-fourth times, which is the cylinder ratio. 
 
2G 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 The early practice in this country with two- 
 cylinder compounds gave a ratio of two to one 
 or even less, but extended experiment has dem- 
 
 onstrated that a greater 
 proportion than this is 
 advisable and man y 
 compounds of this class 
 have a low-pressure cyl- 
 inder from two and one- 
 half to two and three- 
 quarters times larger 
 than their high-pressure 
 cylinder. The Baldwin 
 works used a ratio of 3 
 to 1 in their Vauclain 
 
 pounds for both passenger and freight service for 
 
 a number of years and consider the results emi- 
 
 nently satisfactory, while 
 
 the builders of the Brooks 
 
 tandem four-cylinder 
 
 compound advise a ratio 
 
 of between 2.8 and 3 to 1. 
 
 However, the whole prob- 
 
 lem of cylinder ratios for 
 
 compound locomotives is 
 
 based upon the desirabil- 
 
 ity of dividing the work 
 
 as equally as possible be- 
 
 tween the high and the 
 
 low-pressure cylinders, and 
 
 without going into details, it is apparent that no 
 
 given ratio will keep the work equally divided 
 
 00 
 
 
 
CLASSES OF COMPOUND LOCOMOTIVES. 27 
 
 for different service and different points of cut-off, 
 nor should this equal division of power between 
 the cylinders be given anything but secondary 
 consideration in comparison with the total econ- 
 omy of the locomotive. To partially equalize the 
 power of compounds, the amounts of lap and lead 
 are not the same for both cylinders; one builder 
 uses a separate lever in the cab for independ-' 
 ently adjusting the travel of the low-pressure 
 valve, as fully described .elsewhere. 
 
 There seems to be no general rule followed by 
 
 builders in this country 
 as to which cylinder of 
 a two-c y 1 i n d e r com- 
 pound should be placed 
 on the right-hand or 
 engineer's side of the 
 engine. Generally the 
 intercepting valves are 
 located on the engi- 
 neer's side to make their 
 connections as simple as 
 possible, and hence, ac- 
 cording as the design 
 contemplates the plac- 
 ing of this valve adjacent to the high or the low- 
 pressure cylinder, that one is placed on the right- 
 hand side. But even this rule is not without 
 exception.* 
 
 *It, would seem as though the intercepting valve, if placed 
 between the high-pressure cylinder and the receiver, would cause 
 less wire-drawing of steam to the low-pressure cylinder than if 
 located between the latter and the receiver. 
 
28 ENGINEERS' AND FIREMEN'* MANUAL. 
 
 Some compounds have cylinder casings both of 
 the same size, but with the advent of the thirty- 
 four or thirty-five inch low-pressure cylinder it 
 seemed to many advisable to place it on the 
 engineer's side with the thought of its better pro- 
 tection from damage if within his vision, and, fur- 
 thermore, that the high-pressure cylinder casing 
 be made no larger than necessary for reason of 
 its better protection from accident. 
 
 It is becoming the general practice on com- 
 pounds of any size to place combination safety and 
 relief valves on the receiver and the low-pressure 
 chest and cylinder heads to avoid damage in case 
 of broken reducing valve or other accident that 
 might produce unsafe pressure on that side. 
 
CHAPTER IV. 
 
 ENGINEERS' AND FIREMEN'S MANUAL QUESTIONS 
 AND ANSWERS ON THE OPERATION OF COM- 
 POUND LOCOMOTIVES IN GENERAL. 
 
 In what respects should the instructions for 
 firing compound locomotives differ from those for 
 single-expansion engines, as described in the 
 Manual ? On account of the effect of the milder 
 exhaust on the fire, the fireman should carry the 
 fire as light as possible and yet keep a thin layer 
 of coal in a well ignited state over the entire 
 surface of the grates. 
 
 Should the engineer observe any difference 
 between the operation of a compound and a 
 simple locomotive ? Perhaps the most important 
 thing is that the engineer must accustom himself 
 to use the reverse lever for what it is intended, 
 not hesitating to increase the valve travel when- 
 ever necessary, and converting the engine to 
 "simple" only at low speeds and after the maxi- 
 mum power of the engine working compound is 
 found insufficient. There will be no such waste 
 of steam from lack of expansion (see Fig. 100) 
 nor such serious injury to the fire by working the 
 valves full gear as is the result with single-expan- 
 sion engines. Do not expect to find the best run- 
 ning position of the reverse lever as near the cen- 
 ter of the quadrant as with a simple engine. The 
 engine will do better work with the lever nearer 
 
 (29) 
 
30 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 full gear, just how far depending, of course, on 
 the varying conditions of train, grade, and speed; 
 but, in general, do not cut the lever back too far. 
 The engine throttle should usually be run as 
 wide open as possible, but judgment must be 
 used in this respect according to the existing cir- 
 cumstances. An engine designed for heavy 
 freight service may do better under very light 
 work or in passenger service, if throttled. 
 
 In order to move and stop engines quickly 
 when desired, as for engine-house or turn-table 
 work, how is it advisable that compound engines 
 be handled? Their valves should be kept in 
 simple or starting position whenever their con- 
 struction will permit, in order that the engines 
 may be moved with the least necessary opening 
 of the throttle and that, when the throttle is 
 closed, the pressure remaining in the pipes will 
 the sooner escape. 
 
 In starting, why are compounds more likely to 
 slip than other engines? If they are started 
 working simple, their power temporarily is con- 
 siderably greater than that of simple engines of 
 the same weight, hence great care should be 
 exercised by the engineer to avoid slipping; but 
 at any rate the cylinder cocks should be left open 
 as long as there is any liability of water being in 
 the cylinders. 
 
 Why is it, that, under these circumstances, com- 
 pound locomotives frequently slip only a part of 
 a turn instead of spinning around, as many 
 simple engines will do unless steam is immedi- 
 ately shut off? Because, while they are more 
 
OPERATION OF COMPOUND LOCOMOTIVES. 31 
 
 powerful at slow piston speeds, the ports used for 
 starting are generally so small that a rapid 
 movement of the piston will so greatly reduce 
 the effective pressure on the piston as to cause 
 the slipping to cease, many times without closing 
 the throttle. 
 
 What harm results from frequent slipping for 
 only a part of a revolution? This will occur each 
 time at that part of the stroke where the turning 
 power is the greatest and finally wear the tires 
 out of round, so that the wheels will pound badly 
 at high speeds, thus causing damage to the 
 machinery and track besides making the engine 
 ride hard. 
 
 Wherein does the lubrication of their cylinders 
 differ from that of simple engines? Oil need 
 only be supplied to the high-pressure cylinder or 
 cylinders, when the engine is working compound. 
 Hence a four-cylinder compound would be lubri- 
 cated, as usual, OB both sides of the engine, but 
 a two-cylinder, or cross-compound, would require 
 oil only in the one high-pressure cylinder when 
 working in compound position. In this latter 
 class, valve oil should be supplied to the low- 
 pressure cylinder, however, when the engine is 
 starting or running simple, but immediately shut 
 off as soon as the change is made to compound 
 working. 
 
 What are apt to be the injurious consequences 
 of feeding oil to the low-pressure side when the 
 engine is working compound ? There being then 
 no supply of live steam through the reducing and 
 the intercepting valves, the oil would settle there 
 
32 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 and gum these valves so as to cause them to 
 stick and, possibly, become inoperative. 
 
 When is it advisable to work the compound as 
 a simple engine? In starting very heavy trains, 
 and also on heavy grades when it is seen that 
 the power as a compound with the valve in full 
 gear is insufficient. 
 
 When the engine can be run simple for any 
 period at the will of the engineer, above what 
 speed is it impracticable to do so? Above a 
 speed exceeding six or eight miles an hour. 
 
 What is the reason for this? Because, as out- 
 lined elsewhere, the special ports for use when 
 the compound locomotive is working simple are 
 usually purposely designed too small to permit 
 of much speed. 
 
 If special valves for use when the engine is 
 drifting are not provided, what is it advisable to 
 do? Work a little steam all the time in order to 
 keep the large valves and pistons somewhat lub- 
 ricated. 
 
 Why is it more difficult to detect leaky valves 
 and cylinder packing in compound than in simple 
 engines? In the first place it does not so 
 seriously affect the good working of the engine, 
 and, in the second place, because the high-pressure 
 cylinder does not exhaust to the atmosphere 
 where a blow could be heard, and also the 
 pressure behind the low-pressure piston is very 
 much lower than with a simple engine and, con- 
 sequently, a blow does not sound as loud. 
 
 What general rule will apply to compound as 
 well as simple locomotives where one side has to 
 
OPERATION 'OF COMPOUND LOCOMOTI VES. 33 
 
 be disconnected in cases of accident? On the 
 disabled side, always block securely at both ends 
 of the crosshead and firmly secure the valve, under 
 all ordinary circumstances, in the center of its 
 seat? 
 
 What is usually the cut-off in the high-pres- 
 sure cylinder with the reverse lever hooked up? 
 Some builders cut no notches higher up in the 
 quadrant than would give a cut-off at one-half 
 stroke, w r hile others notch the quadrant all the 
 way up to the center. 
 
 Why is it not necessary to have notches in the 
 quadrant for shorter cut-off than one-half? A 
 shorter cut-off than one-half for a compound loco- 
 motive is generally inadvisable for reasons anal- 
 agous to those hereinbefore urged against a shorter 
 cut-off than one-fourth for a simple locomotive; 
 also it prevents damage that might ensue from 
 excessive compression. With a ratio of 2 to 1 be- 
 tween the sizes of the low and the high-pressure cyl- 
 inders, one-half cut-off gives practically four ex- 
 pansions, a three-fourths cut-off gives two and two- 
 thirds expansions; with a cylinder ratio of 3 to 
 1, one-half cut-off gives about six, and three- 
 fourths cut-off about four expansions. Fig. 100 
 clearly shows, that, while the most economical 
 cut-off (as far as the amount of steam used is 
 concerned) is about one-quarter of the stroke for 
 single-expansion engines, it is about one-half 
 stroke for compounds. Lighter work than is 
 produced by full throttle and one-half cut-off in 
 the high-pressure cylinder can best be obtained 
 by throttling the engine. 
 
34 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 In what way does the use of a separate exhaust 
 valve give greater power to the two-cylinder com- 
 pound at slow speeds? Assuming 200 pounds 
 boiler pressure and a cylinder ratio of 2i to 
 1, the high-pressure exhaust reaches about 57 
 pounds when the engine is working compound. 
 This pressure is the receiver pressure and becomes 
 the initial pressure (at slow speeds) in the low- 
 pressure cylinder. When working simple, the 
 reducing valve permits about 80 pounds of live 
 steam to pass into the low-pressure cylinder, thus 
 considerably increasing the power in that cylin- 
 der. The high-pressure piston also exerts an 
 equally increased power when working simple, 
 as the back pressure of 57 pounds is removed by 
 the separate exhaust valve. 
 
 THE BALDWIN FOUR-CYLINDER COMPOUND. 
 
 The builders of the "Vauclain" four-cylinder 
 compound locomotives claim a design productive 
 of the greatest efficiency with the utmost sim- 
 plicity of parts and the least possible deviation 
 from existing practice; that they also develop 
 equal power on each side of the locomotive, 
 thereby preventing the racking of the machinery 
 resulting from an unequal distribution of power; 
 and that, in their method of handling by the 
 engineer, there is but slight departure from that 
 of single-expansion or non-compound locomo- 
 tives. They may be started, and run for any de- 
 sired length of time, either simple or compound, 
 at the will of the engineer, and can be changed 
 from the one to the other at his discretion by the 
 
OP EH AT ION OF COMPOUND LOCOMOTIVES. 
 
 35 
 
 movement of a small lever in the cab which also 
 operates the cylinder cocks. 
 
 The principal features of construction are as 
 follows: 
 
 The cylinders consist of one high-pressure and 
 one low-pressure cylinder for each side, the ratio 
 of their volumes being as nearly 3 to 1 as the 
 employment of convenient measurements will 
 allow. They are cast in one piece with the cylin- 
 drical valve chamber and the saddle, the cylin- 
 
 fig. 
 
 ders being placed one directly above the other 
 and as close together as they can be with ade- 
 quate walls between them. Figs. 113 and 114 
 show the proximity of the two cylinders, while 
 in Fig. 115, which shows the arrangement of the 
 cylinders in relation to the valve, the actual con- 
 struction is distorted for illustrative purposes. 
 
 The valve used to distribute the steam to the 
 cylinders is of the piston type, working in a cyl- 
 indrical steam chest located in the saddle of 
 
36 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 the cylinder casting as close to the cylinders as 
 possible and between them and the smoke-box, 
 as shown in the figures. This chest, having 
 steam passages cast larger than required, is 
 bored out enough larger than the diameter of 
 the piston valve to permit the use of a hard cast 
 iron bushing. Fig. 122 shows this bushing and 
 one method of forcing it into place so that steam 
 tight joints will be had between all ports; it 
 
 also shows the narrow bridges across the steam 
 ports which prevent the eight packing rings of 
 the valve (shown in Fig. 116) from entering the 
 ports. These cast iron packing rings form the 
 edges of the valve. 
 
 The valve is of the piston type double, and 
 hollow between the two inside pistons but hav- 
 ing two solid ends, as shown by Fig. 116, and 
 controls the admission and exhaust of both cylin- 
 ders. The exhaust steam from the high-pressure 
 
OPERATION OF COMPOUND LOCOMOTIVES, 37 
 
 cylinder becomes the supply steam for the low- 
 pressure cylinder and is transmitted from one 
 side of the high-pressure cylinder to the opposite 
 
 Tiff. 
 
 side of the low-pressure cylinder through the hol- 
 low portion of the valve, as indicated by arrows, 
 Fig. 115. The supply steam for the high-pressure 
 
38 
 
 ENGINEERS' AND FIREMEN'S MANUAL, 
 
 cylinder enters the steam chest at both ends, 
 thus balancing the valve with the exception of 
 the area of the valve-stem at the back end. 
 
 The more common slide valve action being so 
 much better understood by the average railroad 
 man than the piston valve, I will liken this four- 
 piston valve to one slide valve within another 
 having external admission and internal exhaust in 
 both cases. Thus it will be seen that the outside 
 
 'a. 116. 
 
 edges of the two outer pistons govern admission 
 and their inside edges the exhaust of high-pres- 
 sure cylinder, while the two inner pistons simi- 
 larly regulate the flow of steam to and from the 
 low-pressure cylinder, all of which will be evident 
 by a reference to the arrows in Fig. 115. 
 
 Where the front rails of the frame are single 
 bars, the high-pressure cylinder is usually put on 
 top, as shown in Fig. 113, and in that event, with 
 
OPERATION OF COMPOUND LOCOMOTl } 'EH. 39 
 
 the usual rocker-arm, indirect valve motion is 
 used.* When the low-pressure cylinder is put 
 above (Fig. 114) on account of the double front 
 rails of the frame, they also prevent the use of 
 the rocker-shaft and box and the valve motion is 
 then termed direct-acting, which necessitates a 
 different location of the eccentrics on the axle.'* 
 
 Engineers and those employed in shops and 
 round-houses for setting valves and eccentrics 
 should thoroughly understand the difference be- 
 tween the position of the eccentrics with relation 
 
 
 
 to the crank-pins for direct and indirect valve 
 motion, as given fully elsewhere in the Manual, 
 and further brought out in the Catechism on 
 Accidents to Baldwin Four-Cylinder Compounds 
 hereinafter contained. 
 
 The style of crosshead is shown in Fig. 117. 
 It is made of cast steel, to insure the greatest 
 strength with a minimum weight, the wearing 
 surface being lined with tin. The piston, shown 
 
 *Direct and indirect valve motion will be found fully illus- 
 trated and explained in the earlier chapters of the Manual. 
 
40 
 
 ENGINEERS' AND FIREMEX\* M.INUAL. 
 
 in Fig. 118, is also preferably made with cast 
 steel heads, the object in both cases being to re- 
 duce the weight of the reciprocating parts to a 
 minimum. 
 
 It is obvious, that, in starting these locomotives 
 from a state of rest with heavy trains, it is neces- 
 sary to obtain a greater power than that exerted 
 by the high-pressure piston alone, for there would 
 
 Fig.129 
 
 be no pressure on the low-pressure piston until 
 the high-pressure cylinder had made one exhaust; 
 hence it is necessary to admit steam to the low- 
 pressure as well as the high-pressure cylinders. 
 This is accomplished by the use of the starting 
 
OP EH AT ION OF COMPOUND LOGOMOTI VES. 4 1 
 
 valve (Fig. 119).* This is simply a plug-cock 
 which is opened by the engineer by means of 
 suitable levers from the cab, to admit steam from 
 one end of the high-pressure cylinder to the other, 
 and thence, as if it were the ordinary high-pres- 
 sure exhaust, into the low-pressure cylinder. This 
 same valve acts as a cylinder cock for both ends 
 of the high-pressure cylinder and is operated by 
 the same lever that actuates the ordinary cylin- 
 der cocks, which are in this case on the low-pressure 
 cylinder, thus making, probably, the most simple 
 starting device used on any compound locomotive 
 and one not easily deranged. The operation of 
 the starting valve in conjunction with the cylin- 
 der cocks is clearly shown in Fig. 120. The 
 starting valve should be kept closed (position 'N) 
 as much as possible, as its indiscriminate use 
 reduces the economy and makes the locomotive 
 
 "logy."t 
 
 Air valves, to prevent a vacuum, are placed in 
 the steam passages of the high-pressure cylinder, 
 
 *This is sometimes called the "By-Pass" valve, as it connects 
 the two sides of the high-pressure piston, but for an entirely dif- 
 ferent purpose than that to which the by-pass valves are put in 
 connection with the low-pressure cylinder as described herein- 
 after under the Richmond and the Rogers compound, and for that 
 reason I have not called it a "by-pass" valve. Two earlier 
 forms of starting valves have been used with Vauclain com- 
 pounds, but, inasmuch as they have been superseded by this form 
 of valve, it is not deemed necessary to illustrate and describe 
 them herein. 
 
 fAn engine which should be capable of high speed but is not, 
 and in which the pressures work against themselves in the cyl- 
 inders, is said to be "logy." 
 
42 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 a practice now generally followed on all locomo- 
 tives, either simple or compound. Additional air 
 valves, marked C and 6 T| in Fig. 120, are placed 
 in connection with the ports in the valve cham- 
 ber leading to the low-pressure cylinders. Air 
 valves of somewhat different shape have been 
 described and shown in detail heretofore in the 
 Manual. 
 
 Water relief valves W W, Figs. 120 and 121, 
 which are nothing more nor less than pop valves, 
 are applied to the low-pressure cylinders and at- 
 tached to the front and back cylinder heads to re- 
 lieve excessive pressure of any kind, steam or 
 water. The spring in the water relief valves on 
 these engines is made to carry a pressure enough 
 greater than the boiler pressure to prevent their 
 discharging steam and water ordinarily in start- 
 ing the engine simple. 
 
 In all other respects the locomotive is the same 
 as the ordinary single expansion locomotive. 
 
 Operation of the Baldwin Four-Cylinder Com- 
 pound. When starting the locomotive, the engi- 
 neer should, ordinarily, pull the cylinder cock 
 lever way back and thus open the cylinder cocks 
 in order to relieve the cylinders of condensation, 
 and, as the starting valve is opened by the same 
 movement, steam is thus admitted to the low- 
 pressure cylinder and the locomotive started 
 quickly and freely. 
 
 In case the locomotive is at a platform of a 
 crowded station, or in any other place where it is 
 
OPERATION OF COMPOUND LOCOMOTI VES. 
 
 43 
 
 undesirable to open the cylinder cocks, the en- 
 gineer should move the starting lever in the 
 opposite direction from that usually given it, 
 
 JigJZO. 
 
 placing the starting valve handle in position J, 
 Figs. 119 and 120; that is, heshould pushforward 
 the lever in the cab, thus allowing steam to pass 
 
44 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 through the starting valve without opening either 
 the low-pressure cylinder cocks or the drip C of 
 the starting valves. By further reference to Fig. 
 119, it will be seen how, when the handle is in po- 
 sition K, ports A, B, and drip C are all connected 
 by the ports a, b, and c of the plug; but if the handle 
 is in the opposite position J, ports A and B only 
 are connected, as b is .now at a and c is opposite 
 B', in its central position N (normal position for 
 compound working), it will be seen that all ports 
 are closed as in the figure. 
 
 Tig. J 21. 
 
 rrtn JZur-Cg/exafc 
 
 After a few revolutions have been made and 
 the cylinders are free from water caused by con- 
 densation or priming, the engineer should move 
 the cylinder cock lever into the central position, N, 
 causing the engine to work compound entirely. 
 This should be done before the reverse lever is 
 disturbed from its full gear position. 
 
 Ordinarily, the reverse lever should not be 
 "hooked up," thereby shortening the travel of 
 
OPERATION OF COMPOUND LOCOMOTI VES. 45 
 
 the valve, until after the cylinder cock lever has 
 been placed in its central position, but it is often 
 necessary to open the cylinder cocks when at 
 full speed to allow water caused by priming or 
 foaming to escape from the cylinders, and in such 
 cases no disadvantage is experienced, and the 
 reverse lever need not be disturbed. 
 
 The starting device is simply designed for 
 use in the starting of the train and should not be 
 used at any other time unless there is imminent 
 danger of stalling and the lever has been previ- 
 ously dropped to full gear. In other respects, 
 
 aside from these here noted, the rules governing 
 the operation of compound locomotives in gen- 
 eral should be clearly understood by any engineer 
 who is liable to be called upon to run a compound 
 locomotive of this or other design. 
 
 REPAIRS. 
 
 The builders of the Vauclain four-cylinder 
 compound claim an advantage in it over the 
 
46 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 two-cylinder or " cross-compound " locomotive 
 in simplicity of parts, there being no intercept- 
 ing valve,* and a similarity to all the parts of a 
 single-expansion locomotive. Thus its repairs 
 will be similar to those of simple locomotives. 
 To carry out this simplicity of parts, the piston 
 rods of the high and low-pressure cylinders are 
 of the same diameter and designed strong enough 
 to withstand the severest strains of service. 
 
 The packing rings in the valves are easily 
 replaced and the valve chest bushing can be 
 cheaply and easily renewed. In extracting old 
 bushings it is best to split them between the 
 ports with a narrow chisel. The new bushings 
 can be pressed in by some such handy device as 
 that shown in Fig. 122. 
 
 Accidents to Ba Idwin Four- Cylinder ( " Vauclain" ) 
 Compounds. For all ordinary accidents, such as 
 broken main rod or pin, or a broken valve stem, 
 what should be done? The same as for non- 
 compound or simple locomotives, as described 
 fully in the earlier chapters of the Manual. 
 
 With a low-pressure cylinder head knocked 
 out, would it be necessary to disconnect that 
 side ? Not for a short distance. 
 
 In that event, how many exhausts would there 
 be during one revolution ? There would be three 
 
 *The intercepting valve is the valve which prevents the live 
 steam which is admitted from the boiler to the low-pressure cyl- 
 inder at certain times, from passing through the receiver to the 
 high-pressure cylinder where it would produce back pressure on 
 the piston. 
 
OPERATION OF COMPOUND LOCOMOTI VEti. 47 
 
 in the stack and one through the open cylinder 
 head and the latter exhaust might obstruct the 
 engineer's view, if on his side, and render the 
 procedure inadvisable. 
 
 With the Vauclain Compound, at what posi- 
 tion of the reverse lever is work of the two 
 cylinders most nearly equalized ? At a cut-off 
 of about one-half the stroke in the high-pressure 
 cylinder. 
 
 When is the work most unequal and the 
 strains on the crosshead consequently the great- 
 est ? In starting with the engine working sim- 
 ple, as then the high-pressure piston is nearly 
 balanced by live steam on both sides and the 
 low-pressure cylinder obtains approximately boiler 
 pressure. 
 
 What results would be likely should the rig- 
 ging of the cylinder cocks and starting valve 
 become bent or disconnected ? Should one start- 
 ing valve fail to properly close, the exhausts 
 would be of unequal intensity. If one of them 
 failed to open when required in starting, the 
 engine would be weak on that side as it would 
 have to start compound, that is with steam for the 
 first stroke in the small high-pressure cylinder 
 only. 
 
 In this latter event, when would the first 
 exhaust from that side take place ? Not until 
 the completion of the return stroke. 
 
 If the cylinder cocks open and close with the 
 same rigging as the by-pass valve, why would not 
 the engineer know thereby that the by-pass valve 
 was in position desired ? From the previous 
 
48 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 description of this rigging, shown in Figs. 119 
 and 120, it should be remembered that the cab 
 lever pushed clear ahead opens the by-pass valve, 
 but not its drip nor the cylinder cocks. 
 
 Before altering the valve motion, what else 
 should be examined if the exhausts were of un- 
 equal intensity ? Examine for broken packing 
 rings in the piston valve or the low-pressure 
 cylinder.* 
 
 Jn case a valve-stem broke off inside the chest 
 or the valve itself broke, would it be certain of 
 discovery at once, as with an ordinary slide valve ? 
 Possibly it would not. Instances have been cited 
 where compound locomotives of this system have 
 hauled passenger trains long distances with bro- 
 ken valve-stems and broken valves. The two 
 ends of the valve being unbalanced by the area 
 of the valve-stem (see Figs. 115 and 116) accounts 
 for the first possibility, while live steam from the 
 induction ports acting on ea,ch end of the valve 
 would explain the case of an undetected broken 
 valve. 
 
 How can it be found if the cylinder packing 
 in the high-pressure cylinder is blowing? Put 
 the engine on the quarter, block the wheels, and 
 test as usual for leaky slide valve; then, with the 
 starting valve closed (in compound position) and 
 the low-pressure cylinder cocks blocked open, 
 
 *A case is cited by the builders where an engineer ran his 
 locomotive two days without any piston head at all in one of the 
 high-pressure cylinders," and even then could not tell what was 
 the matter except that the intensity of the exhausts were unequal 
 and the engine did not make good time. Machinists put to work 
 to locate the trouble, found it to the great surprise of the engineer. 
 
OPERATION OF COMPOUND LOCOMOTIVES. 
 
 49 
 
 drop the reverse lever into full gear. Steam 
 passing the high-pressure piston will appear at 
 the open cylinder cock of the low-pressure cyl- 
 inder, but at the opposite end that would be 
 expected with a simple engine. 
 
 How can it be found if the packing in the low- 
 pressure cylinder is blowing ? Put the engine 
 on the quarter and open the starting valve and 
 cylinder cocks and look for any escape of steam 
 from the low-pressure cylinder cock on the end 
 that should be in exhaust, as with a simple engine. 
 
 . /23. 
 
 With the four-cylinder type, where the large 
 low-pressure cylinder is placed on top, as in Fig. 
 114, and direct valve motion is employed, how 
 should the eccentric rods on one side stand with 
 the same side of the engine on the forward cen- 
 ter ? They should be crossed, as shown in skel- 
 eton Fig. 123. A slipped eccentric should be 
 set the same as for similar valve motion on a 
 simple engine, as fully described heretofore in the 
 Manual under "Third Examination of Firemen." 
 
50 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 THE BALDWIN TWO-CYLINDER COMPOUND. 
 
 The original Baldwin two-cylinder compound, 
 built in the year 1892, was of the cross-compound 
 receiver type and, after the first stroke or tw r o, 
 
 or as soon as the receiver had attained a pressure 
 of 100 Ibs., the engine automatically changed to 
 compound and could not be operated otherwise. 
 It belonged, therefore, to the automatic class of 
 compounds. The reducing and the starting valve 
 
OPERATION OF COMP OUND L OC OMOTI VES. 5 1 
 
 then employed were changed materially in the 
 later design of the two-cylinder compound here- 
 with illustrated and described. 
 
 Their later two-cylinder compound locomo- 
 tives belong to the class of convertible com- 
 pounds, as they can be operated either simple or 
 compound for any length of time by the move- 
 ment of a small valve in the cab, as shown by 
 Fig. 128. 
 
 Fig. 124 shows a front view, giving the gen- 
 eral arrangement of cylinders, steam, exhaust and 
 receiver pipes in the front end, and the location 
 of the intercepting and reducing valve in the 
 saddle of the high-pressure cylinder. The low- 
 pressure cylinder derives all its pressure from the 
 receiver when running compound, as is usual in 
 two-cylinder compounds. 
 
 The office of the intercepting valve is two-fold. 
 It acts as an intercepting valve by opening and 
 closing communication between the two cylin- 
 ders, and also as a separate exhaust valve, by con- 
 necting the low-pressure cylinder with the exhaust 
 to the stack. This it does by diverting the ex- 
 haust from the high-pressure cylinder either into 
 the atmosphere, when working single-expansion, 
 or into the receiver, when working compound, 
 and is operated at the will of the engineer. 
 
 The office of the reducing valve is to admit 
 live steam at a reduced pressure into the receiver 
 and thence to the low-pressure cylinder, when 
 the engine is working single-expansion, and also 
 to close simultaneously with the changing of the 
 intercepting valve to the position which causes 
 
52 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 the engine to work compound, so that the receiver 
 will obtain no live steam from boiler when taking 
 the exhaust from high-pressure cylinder. The 
 performance of the first above-mentioned func- 
 tion that of reducing the pressure of live steam 
 delivered to the receiver is necessary in order 
 
 that the total pressure on the large low-pressure 
 piston shall not be greater than that on the high- 
 pressure piston, and thus the low-pressure side 
 kept from jerking the train and producing unequal 
 strains on the two sides of the locomotive when 
 working as a simple engine. 
 
OPERATION OF COMPOUND LOCOMOTI VEX. 53 
 
 Operation of the intercepting and reduction 
 valves. In Figs. 125 and 126 the intercepting 
 valve is marked A and the reducing valve C. 
 It will be seen that they are both cylindrical in 
 
 ~Pipelo Operattnlj 
 ledve in Cab 
 
 form, are placed in bushings having suitable ports, 
 and that coil springs hold them in their normal 
 positions when no pressure is acting against them 
 to overcome these springs. 
 
54 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 In the cab of the locomotive is placed an oper- 
 ating valve, shown in Figs. 127 and 128, having 
 two positions, marked "SIMPLE" and "COMPOUND." 
 Through this operating valve a pressure of air or 
 live steam is admitted to one side of the reducing 
 and the intercepting valves through two pipes 
 marked DD, and, acting against the right end of 
 valve A and against the left end of valve C, moves 
 both from their normal positions shown in Fig. 
 125 to those of Fig 126. 
 
 The reducing valve C, when it is not closed 
 permanently by live steam from the operating 
 pipe D, is automatically closed when the pressure 
 in the receiver R is great enough to produce as 
 much power in the large low-pressure cylinder as 
 is obtained in the smaller high-pressure cylinder. 
 For this purpose steam from the receiver E can 
 pass through a port E, raising the poppet valve F 
 (which remains open as long as the engine is not 
 working compound) and bears upon the larger 
 end of the reducing valve C, causing it to move to 
 the right and close the live steam passage H 
 (shown in Fig. 125) leading to the receiver E, 
 whenever the receiver pressure becomes excessive. 
 Thus it will be seen that when the engine is work- 
 ing simple there must be a close balance between 
 the left-hand larger end of the reducing valve, 
 being acted upon by receiver pressure, and the 
 right-hand smaller end of the reducing valve, 
 being acted upon by live steam from the main 
 steam pipe S. In this way is the receiver pressure 
 kept as much lower than the boiler pressure as 
 the large end of the reducing valve is greater than 
 
OPERATION OF COMPOUND LOCOMOTIVES, 
 
 55 
 
 the small end. This proportion is relative to the 
 respective sizes of the high and the low-pressure 
 cylinders and hence equal cylinder power will be 
 given both sides of the engine in working simple. 
 When the engine is standing, the lever of the 
 small operating valve, Figs. 127 and 128, in the 
 cab should be placed at position marked "SIMPLE," 
 and the valves are then in position for the engine 
 to work as a single-expansion locomotive, as the 
 
 steam pressure is relieved 
 through this cab valve from 
 the large end of the reducing 
 valve and the right-hand end 
 of the intercepting valve, al- 
 lowing these valves to as- 
 sume (by the action of their 
 springs) their respective posi- 
 itions shown in Fig. 125. The 
 arrows in this figure illus- 
 trate clearly how the steam 
 can pass from the high-pres- 
 sure exhaust through the 
 intercepting valve A to the 
 independent exhaust B lead- 
 ing to the stack (see dotted lines and arrows). At 
 the same time the passage of live steam to the re- 
 ceiver from which the low-pressure cylinder 
 receives its supply takes place through ports H, 
 as shown by other arrows. The receiver pressure 
 is governed by the automatic action of the reduc- 
 ing valve, as previously explained. 
 
 Thus the engine can be used as a single-expan- 
 sion locomotive in making up and starting trains, 
 
Ob ENGINEERS' AND FIREMEN'S MANTTAL. 
 
 and then, at the will of the engineer, the operat- 
 ing valve, Figs. 127 and 128, in the cab can be 
 moved to the position marked "COMPOUND." This 
 will admit live steam through the two supply 
 pipes D, thence to the cylinders marked Wand 
 C 1 , Fig. 126, changing the intercepting and the 
 reducing valves quickly, and, as the ports are 
 small, noiselessly, to the position shown in the 
 latter figure. With the intercepting valve in this 
 position it will be seen that the independent ex- 
 haust B is closed and steam from the high-pressure 
 exhaust must follow the course of the arrows to 
 the receiver, passing around the small reduc- 
 ing valve bushing and its valve C which is kept 
 closed by the live steam from pipe D. 
 
 At any time the engineer may desire to in- 
 crease the power of the engine as, for instance, 
 when in danger of stalling, by moving the lever 
 of the operating valve in the cab to position 
 marked "SIMPLE "the engine is again changed 
 at once to a single-expansion locomotive. 
 
 Accidents to Baldwin Two-Cylinder Compounds. 
 With one side disabled, what should be done in 
 order to safely run the engine in ? Disconnect 
 the disabled side, as advised for simple engines, 
 place the intercepting valve in position for work- 
 ing simple so as to open the separate exhaust 
 port, and run in with one side. 
 
 Should the small pipes DD leading to the reduc- 
 ing valve C and the intercepting valve piston be 
 broken off, how could the engine be worked ? 
 With single-expansion only, unless the back head 
 of the separate exhaust chamber TFwere removed 
 
OPERATION OF COMPOUND LOCOMOTI VES. 57 
 
 and the piston blocked in the position shown in 
 Fig. 126; then the engine would become an auto- 
 matic compound, that is, would start simple but 
 automatically go to compound after a revolution 
 or so. 
 
 What would it be advisable to do in case of a 
 broken reducing valve ? Use very light throttle at 
 slow speeds, or run with a reduced boiler pressure. 
 
 Should the small valves F and G be frequently 
 inspected and cleaned? Yes. These valves and the 
 reducing and the intercepting calves become 
 gummed by the injudicious use of cylinder oil on 
 the low-pressure side. 
 
 THE SCHENECTADY COMPOUND. 
 
 Locomotives built by the Schenectady Loco- 
 motive Works are oftentimes styled by the older 
 railway men as " McQueen" engines, although 
 the name of the builders has been as at present 
 for many years. 
 
 These builders have constructed many com- 
 pound locomotives, and, including the original 
 valve design, have employed three styles of com- 
 pound mechanisms, but all engines built have 
 been of the two-cylinder variety of compounds. 
 
 Original Schenectady Type. The original design 
 by their then superintendent, Mr. A. J. Pitkin, 
 consisted of an intercepting valve and a reducing 
 valve. The stem of the intercepting valve was 
 connected by levers to an index in the cab, which 
 showed its position to the engineer. These engines 
 belonged to the class of automatic compounds. 
 
58 ENGINEERS' ANU FIREMEN'S MANUAL. 
 
 In starting the engine, a small pipe from the 
 boiler through a reducing valve supplied steam 
 to the low-pressure cylinder at a reduced pressure. 
 When the receiver had accumulated sufficient 
 pressure by the exhaust into it from the high- 
 pressure cylinder, the intercepting valve would 
 automatically be thrown to its normal position 
 for working compound; then the supply of live 
 steam to the low-pressure cylinder was cut off 
 and the receiver pressure admitted, and thus the 
 engine worked compound. 
 
 The following modification of this valve ar- 
 rangement was afterwards made by Mr. Pitkin 
 and applied to many locomotives by the Schenec- 
 tady Locomotive Works. 
 
 Design of 1892. With this construction of 
 1892, the opening of the throttle admits live 
 steam at the same time to both the high and 
 the low-pressure cylinders, closes the intercepting 
 valve and allows the engine to start with its 
 full power as a simple engine. After a few 
 strokes the receiver pressure automatically opens 
 the intercepting valve and cuts off the passage 
 of live steam to the low-pressure cylinder and 
 the engine works compound. The special valves 
 are located in and behind the saddle on the low- 
 pressure side and are operated automatically and 
 beyond the will of the engineer. Fig. 129 shows 
 the general appearance of that portion of the 
 intercepting valve projecting back of the saddle; 
 Figs. 130 and 131 show the valves and pistons 
 removed from their encasing chambers. Upon 
 opening the throttle, a small connection from the 
 
OPERATION OF COMPOUND LOCOMOTIVES. 
 
 59 
 
 steam pipe admits live steam through suitable 
 valves to an actuating piston, the movement of 
 which opens a poppet valve, supplying live 
 steam to the low-pressure cylinder, and also places 
 the intercepting valve so as to close connection 
 between the receiver and the low-pressure steam 
 
 THE INTERCEPTING VALVE. 
 
 1892 
 
 chest. Thus the low-pressure cylinder exhausts 
 to the atmosphere and the high-pressure cylinder 
 into a closed receiver. Sufficient pressure will 
 accumulate in the receiver after a few strokes to 
 move the small valves, thereby moving the actua- 
 ting piston and with it the intercepting valve, to 
 
60 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 such position as will close off live steam to the 
 low-pressure cylinder, and instead admit the 
 receiver pressure, thus working the engine com- 
 pound. 
 
 For the benefit of those interested in the de- 
 tails of this device, a more thorough description 
 of the accompanying figures follows: 
 
 The front view, Fig. 132, shows the general 
 arrangement of cylinders, steam passages, and 
 the intercepting valve. Figs. 133 and 134 both 
 
OPERATION OF COMPOUND LOCOMOTI VES. 6 1 
 
 show the same horizontal section through the 
 saddles and show the intercepting valve and the 
 actuating valves, Fig. 133 showing them in posi- 
 tion for working compound, and Fig. 134 for 
 starting. Fig. 135 gives a vertical section, better 
 showing the passages between the receiver and 
 the low-pressure steam chest, which passages are 
 opened and closed by the double pistons GG 
 which form the intercepting valve. Of the remain- 
 ing figures, 136 and 137 show details of the regu- 
 lating valve, and Fig. 138 an end view of the 
 intercepting pistons GG. The arrows in Figs. 
 133 and 134 indicate the direction of the steam 
 in passing through the apparatus. 
 
 Fig. 132 shows a smoke-box mounted on sad- 
 dles connected with the high and low-pressure 
 cylinders located on opposite sides of the engine 
 and having the necessary admission and exhaust 
 ports. The exhaust port of the high-pressure 
 cylinder is connected by a passage E (see dotted 
 lines in Fig. 132 and full section of port in Figs. 
 133 and 134) with the receiver at R, Fig. 132. 
 The other end of the receiver connects with the 
 inlet passage R 1 (shown also in Fig. 135) leading 
 to the low T -pressure steam chest, and in this 
 passage the intercepting valve GG is located and 
 travels across it to open or close this passage. 
 
 The intercepting valve and the mechanism for 
 operating it are mounted on the saddle of low- 
 pressure cylinder, as before stated, while the live 
 steam pipe S and the high-pressure exhaust pas- 
 sage E are situated in the high-pressure saddle. 
 The low-pressure exhaust passage E 1 is formed 
 
62 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 by the two saddles being bolted together, see 
 Figs. 133 and 134. 
 
 The intercepting valve consists of two pistons 
 GG (having several small holes y through them 
 in order to balance them, see Figs. 135 and 138) 
 mounted at one end of a long piston rod, which 
 
 moves to and fro in a cylinder having four open- 
 ings. The two large openings shown lead from 
 the receiver to the low-pressure steam chest (see 
 Fig. 135) and are closed by the two intercepting 
 pistons GG when the engine is to be started, so 
 that live steam mav be admitted to the low- 
 
OPERATION OF COMPOUND LOCOMOTIVES, 
 
 63 
 
 pressure cylinder without producing a back 
 pressure in the high-pressure cylinder through 
 the receiver. Of the two remaining openings in 
 the valve cylinder, port D leads to the low-pressure 
 steam chest and port F admits steam from the 
 boiler when the apparatus stands in position as 
 shown in Fig. 134. 
 
 The back end of the intercepting piston-rod 
 passes through suitable stuffing boxes to a small 
 cylinder provided with a piston H, which actuates 
 the intercepting valve. This cylinder has a small 
 steam chest, slide valve and admission and exhaust 
 
64 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 ports so similar to those of an ordinary locomo- 
 tive cylinder, that its operation will be made plain 
 by referring to the Figs. 133 and 134, if the move- 
 ments of its slide valve are explained. This 
 
 LJ-T 
 
 small slide valve, Fig. 131, is moved by a stem 
 connecting two pistons, K and K l , of unequal 
 diameter in order to insure their movement in 
 the proper direction at the proper time. The 
 actuation of these pistons, and with them the slide 
 
OPERATION OF COMPOUND LOCOMOTIVES. 
 
 65 
 
 valve, will be made clear by the figures. From 
 Fig. 135 it will be seen that a small pipe R~ leads 
 from the receiver connection R l to this valve 
 mechanism, and from Figs. 133 and 134, that a 
 pipe S l comes from the live steam passage in the 
 saddle and has a small port leading to the actu- 
 ating valves as well as to the poppet valve N. 
 These live steam and receiver connections come 
 to opposite sides of a small piston valve M (Fig. 
 137), which is called the "regulating valve" and 
 travels across two ports leading to the slide valve 
 beneath it, as shown. 
 
 The remainder of this mechanism consists of a 
 balanced poppet valve N, which, when open, ad- 
 mits live steam from pipe $ l through the inter- 
 cepting valve to the low-pressure cylinder in 
 starting. This poppet valve^has a projecting 
 stem on the lower side and is opened and allowed 
 to close by a rocker-arm or bell-crank L, its 
 two positions being shown in Figs. 133 and 134, 
 respectively. 
 
 The operation of the apparatus is as follows: 
 The normal position of the parts when the en- 
 gine is working compound is shown in Fig. 133, 
 in which position steam for the low-pressure 
 
66 WKGlNEE'lt8\ ANT) FTREMEX'x M. \XUAL. 
 
 cylinder comes entirely from the high-pressure 
 exhaust through the receiver. To start the train, 
 the engine throttle is opened as usual. This per- 
 mits steam to pass to the high-pressure side and 
 also through the pipe $ l (Figs. 133 and 136) to 
 the left side of piston valve M (Fig. 137) and 
 down through the adjacent port (as indicated 
 by arrows) to the slide valve chamber, there act- 
 ing between the two pistons K and K l (Figs. 
 131, 133 and 137). The right-hand piston, being 
 the larger, causes a movement of the slide valve 
 from its position shown in Fig. 133 to that shown 
 in Fig. 134, thereby uncovering the steam port 
 to the left of piston H, which it forces with the in- 
 tercepting valve GGto the right. In this position, 
 as shown in Fig. 134, the receiver 
 openings are closed by the pistons 
 GO and the poppet valve N has 
 been opened by the bell-crank L, 
 'thus admitting live steam through 
 the intercepting valve cylinder and 
 port D to the low-pressure steam 
 chest, as indicated by the arrows. Hence it is 
 possible to obtain the full pressure of live steam 
 in the low-pressure cylinder in starting. 
 
 After one or two revolutions the pressure in the 
 receiver, passing down through the small connect- 
 ing port to the right of the larger piston K 1 (Fig. 
 137) overbalances the pressures between the pis- 
 tons, thus moving the slide valve to the left, the 
 position shown in Figs. 133 and 137. According to 
 the ordinary action of a slide valve this reverses 
 the pressures on the actuating piston 77, forcing it 
 
OPERATION OF COMPOUND LOCOMOTT YES. 67 
 
 to the left and opening the intercepting valve. 
 This return movement of the actuating piston H 
 detaches the bell-crank L from the poppet valve 
 N and allows the latter to close before the inter- 
 cepting valve opens. After this the locomotive 
 works compound, the passage of steam being 
 through the high-pressure cylinder to the receiver 
 and thence through the intercepting valve and 
 low-pressure cylinder to the atmosphere, as pre- 
 viously described. 
 
 A difficulty met with in many of the earlier 
 forms of compound mechanism, and to which the 
 reader's attention was called at the beginning of 
 this chapter, namely, the accumulation of dan- 
 gerously high pressure in the receiver when run- 
 ning with the throttle closed, was overcome in 
 this device by an automatic action of the piston 
 valve M and the differential pistons K and K l 
 (Fig. 137), as follows: When the engine is using 
 steam the regulating valve M is always against 
 the right-hand seat, as shown, and this valve only 
 comes into use when running without working 
 steam, as down a long grade. In this case, if the 
 intercepting valve happened to be closed, the 
 action of the engine would cause air-pressure to 
 accumulate in a closed receiver as there would 
 then be no live steam available to cause the 
 actuating device to open the intercepting valve. 
 Hence it is arranged so that air-pressure in the 
 receiver will force the valve M to the left and 
 itself take the place of live steam by passing to 
 the slide valve chamber and down to the right 
 side of the actuating piston H, moving it to the 
 
68 ENGINEERS' AND FIREMEN'S MANUAL. 
 
OPERATION OF COMPOrXD LOCOMOTIVES. 69 
 
 left and opening the intercepting valve, as shown 
 in Fig. 133. Thus the small valve M acts as a 
 safety valve, insuring the opening of the inter- 
 cepting valve when live steam is not being used, 
 and preventing the danger of excessive receiver 
 pressure or the lifting of the high-pressure slide 
 valve off its seat when the engine is running with 
 steam shut off. 
 
 SCHENECTADY 1892 DESIGN, WITH SOUTHERN PACIFIC 
 MODIFICATION. 
 
 To render it possible to run the engine "simple" 
 for any desired period in starting, or to obtain 
 a maximum power in case a train were stall- 
 ing on a heavy grade, the Southern Pacific Co. 
 in 1893 added to many of their Schenectady com- 
 pounds of the 1892 design, a separate exhaust 
 valve located in the smoke-box, as shown in Figs. 
 139 and 140. The reverse lever in the cab, when 
 placed in either of its extreme positions, caused 
 this valve to open and thereby connect the re- 
 ceiver directly with the main exhaust pipe, thus 
 permitting the high-pressure cylinder to exhaust 
 through the receiver directly to the atmosphere, 
 as indicated by arrows in Fig. 139. As the re- 
 ceiver pressure was thus kept down it will be 
 readily understood from the preceding description 
 of the intercepting valve that the latter will 
 remain in starting position as in Fig. 134, and 
 hence the locomotive will work as a simple engine 
 until such time as the engineer pulls the reverse 
 lever higher up on the quadrant and thereby 
 closes the separate exhaust valve. Then the 
 
70 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 intercepting valve automatically assumes the 
 compound position, as in Fig. 133, for reasons 
 hereinbefore explained. 
 
 This modification of the two-cylinder or cross- 
 compound is of especial note inasmuch as it was 
 one of the first in this country which permitted 
 the working of the locomotive as a simple engine 
 for any desired length of time, at the will of the 
 engineer. Its results in practical operation were 
 to greatly reduce the jerking of trains in starting 
 (then a very serious objection to many com- 
 pounds); it gave a greater maximum power at 
 critical periods, and was withal so eminently satis- 
 factory that the reader will notice the majority 
 of the builders of two-cylinder compounds in this 
 country have embodied a separate exhaust valve 
 in their later designs. 
 
 SCHENECTADY COMPOUND DESIGN OF 1896. 
 
 The valve arrangement designed in 1896 by 
 Messrs. A. J. Pitkin, Vice-President and General 
 Manager, and J. E. Sague, Mechanical Engineer of 
 the Schenectady Locomotive Works, and used as 
 their standard construction for two-cylinder com- 
 pound locomotives, will be made clear by what 
 follows. 
 
 In general it may be said that this so-called 
 "intercepting valve' ' consists of four separate 
 parts, namely: (1) An intercepting valve proper, 
 which allows steam to pass to the low-pressure 
 cylinder from either the receiver or the boiler, 
 according to its position. (2) A reducing valve 
 allowing live steam at only a reduced pressure 
 
OPE RATION OF COMPOUND LOCOMOTT VEX. T I 
 
 to enter the low-pressure cylinder when working 
 simple. ( 3 ) An independent or separate exhaust 
 valve which, when open, vents the exhaust from 
 the high-pressure cylinder to the atmosphere 
 through the exhaust pipe and stack. (4 ) A small 
 valve K inside of the separate exhaust valve, by 
 the use of which the latter can be opened more 
 easily and gradually. 
 
 By the arrangement of these valves the engine 
 can be started and run either compound or simple 
 and can be changed from compound to simple, or 
 the reverse, at the will of the engineer, with the 
 throttle and the reverse lever in any position; the 
 engineer has only to move a small three-way cock 
 in the cab and the working of the engine changes 
 very smoothly and without jerking the train. 
 
72 ENGINEERS' AND FIREMEN'S MANUAL. 
 
OPERATION OF COMPOUND LOCOMOTIVES, 73 
 
74 ENGINEERS' ANU Fl'liE MEN'S M^INUAL. 
 
 Figs. 141 and 142 give sections of smoke arch 
 and cylinder saddles and show the steam passages, 
 the receiver and the location of the intercepting 
 valve in the saddle of the low-pressure cylinder on 
 the right-hand side of the engine. 
 
 It will be noticed by the dotted lines behind 
 the receiver pipe that there are two steam pipes as 
 in a simple engine, but the one (#) leading to the 
 intercepting valve on the low-pressure side is much 
 smaller than usual, as it will only be required for 
 use at low speeds. 
 
 Fig. 143 shows a vertical section lengthwise 
 through the low-pressure cylinder saddle and the 
 intercepting valve (as if they were cut through at 
 MN of Fig. 142) and shows the intercepting 
 and the separate exhaust valves in the position 
 taken when the engine is working simple and re- 
 ceiving live steam in both cylinders. Fig. 144 is 
 a section through the dash-pot of Fig. 143. 
 
 Fig. 145 gives the same section as Fig. 143, but 
 shows the intercepting and the separate exhaust 
 valves in the position taken when the engine is 
 working compound. 
 
 Figs. 146 and 147 show two sections crosswise 
 of the intercepting valve at points indicated re- 
 spectively by the lines cd and ab of Fig. 145. Sec- 
 tion cd shows the passages G for admitting live 
 steam into the low-pressure cylinder, and section 
 a b shows the outlet passage U from the sep- 
 arate exhaust valve to the main exhaust pipe. 
 
 The part which each portion of the valve 
 arrangement performs is as follows: The sepa- 
 rate exhaust valve, when open, allows the steam 
 
OPERATION OF COMPOUND LOCOMOTIVES. 75 
 
 to exhaust from the high-pressure cylinder 
 to the atmosphere without going through the 
 low-pressure cylinder, thus working the en- 
 gine simple; when it is closed, the high-press- 
 ure exhaust must pass through the low-press- 
 ure cylinder, thus working the engine com- 
 
 /Section c-d Section a- 
 
 pound. The intercepting valve closes the 
 passage between the two cylinders when the sep- 
 arate exhaust valve is open, so that steam can- 
 not go from the high-pressure cylinder to the 
 low-pressure cylinder; thus doing away with 
 back pressure on the high-pressure piston when 
 the engine is working simple; it also admits 
 liye steam direct from the dry-pipe through 
 the reducing valve to the low-pressure cylinder. 
 When the separate exhaust valve closes, the 
 intercepting valve automatically opens the pas- 
 
76 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 sage between the two cylinders and cuts off the 
 supply of live steam from the dry pipe to the 
 low-pressure cylinder. The reducing valve works 
 only when the engine is working simple and 
 throttles the steam passing through it, so that 
 the pressure of steam going to the low-pressure 
 cylinder is about one-half (or, less, according to 
 the proportionate sizes of the two cylinders) of 
 that admitted from the boiler to the high-press- 
 ure cylinder. 
 
 The reducing valve is quite heavily cross-sec- 
 tioned, while the long, intercepting valve ap- 
 pears next lighter, in order to render their out- 
 lines in Figs. 143 and 145 readily distinguishable. 
 Examining the two ends of the intercepting valve, 
 it will be seen that the left end, exposed to the 
 pressure of the atmosphere through the drip, is 
 only about three-fourths as large as the right 
 end (between the bridges E R, Fig. 143), exposed 
 to the receiver; hence, if the receiver has little 
 or no pressure, the boiler pressure on the 
 shoulder of the intercepting valve automatically 
 carries it to the right, as shown in Fig. 143. The 
 reducing valve is automatically opened because 
 of the difference in area of its two ends also. The 
 movement of each of these valves is cushioned 
 by dash-pots, as shown. The separate exhaust 
 valve is operated by the engineer by means of a 
 three-way cock in the cab. To open the sepa- 
 rate exhaust valve the handle of the three-way 
 cock is thrown so as to admit a pressure of steam 
 or air through the pipe W against the piston J. 
 Pulling the handle back relieves the pressure 
 
OPERATION OF COMPOUND LOCOMOTI VES. 77 
 
 against piston J and the spring shuts the valve, 
 as in Fig. 145. All the engineer has to do in 
 connection with the operation of the valves is to 
 pull the handle of the three-way cock in the cab 
 one way or the other, according as he wishes the 
 engine to run simple or compound. The engi- 
 neer uses the handle under the following condi- 
 tions: 
 
 To Start Simple. Under ordinary conditions 
 this is not necessary, but if the maximum power 
 of the engine is needed to start a heavy train, the 
 engineer pulls the handle of the three-way cock 
 so as to admit pressure from the cab through 
 pipe W against the piston J, Fig. 145. This will 
 force piston J into the position shown in Fig. 143, 
 opening the separate exhaust valve and hold- 
 ing it open. The engine throttle now being 
 opened, live steam at boiler pressure enters the 
 chamber E from the small steam pipe 8 before 
 mentioned and forces the intercepting valve to 
 the right against the seat FF, as shown in Fig. 
 143. The exhaust steam from the high-pressure 
 cylinder now passes through the receiver and is 
 exhausted through the separate exhaust valve to 
 an annular chamber U connected with the main 
 exhaust to the stack, as indicated by the arrow in 
 Fig. 143. (See also Fig. 147.) Steam also enters 
 the low-pressure cylinder from chamber E through 
 the reducing valve and the annular ports G in 
 the intercepting valve (See Figs. 143 and 146), 
 and is exhausted in the usual way. The reducing 
 valve prevents the full boiler pressure from reach- 
 ing the low-pressure cylinder, As will be seen from 
 
78 ESUISEER& ;LXD FIREMEN S MASUAL. 
 
 Figs. 143 and 145, the reducing valve is partly bal- 
 anced by its smaller left end being open to the at- 
 mosphere through a small groove leading to the 
 chamber having an open drip, and thus the boiler 
 pressure acting on the unbalanced area throws the 
 valve open to the right. When the pressure in 
 the intercepting valve cavity on the right of the 
 reducing valve becomes high enough, it will throw 
 the valve to the left, because it acts on the whole 
 area of the valve; the result is that the steam is 
 throttled to the proper pressure desired for the 
 low-pressure cylinder. 
 
 To Work Compound. Having started the train, 
 when the engineer wishes to change the engine 
 from simple working to compound, he pushes the 
 handle of the three-way cock to its first position 
 which, relieving the pressure on piston J through 
 pipe W, allows the spring to act to the right and 
 close the separate exhaust valve, as in Fig. 145. 
 As soon as this valve is closed the pressure in the 
 receiver, having no outlet, rises and presses the 
 intercepting valve to the left against the pressure 
 from chamber E, which acts only, as stated, 
 upon the shoulder of the intercepting valve. The 
 receiver pressure holds the intercepting valve to 
 the left, as shown in Fig. 145, thereby closing the 
 ports 6r and opening a free passage from the 
 receiver to the low-pressure cylinder as indicated 
 by the arrows, and the engine works compound. 
 While working compound, which is the usual way 
 of working the engine, both the reducing and the 
 intercepting valves are held to the left against 
 ground joint seats. This should prevent any 
 
OPERATION OF COMPOUND LOCOMOTI VES. 7 9 
 
 steam which might leak by. the packing rings 
 from constantly escaping at the drip. 
 
 To Change from Compound to Simple. With 
 the engine running compound, if the engineer 
 wishes to change to simple because of a very 
 heavy grade, he has only to pull the three-way 
 cock handle to the same position as for starting 
 simple. Then piston /first opens the small valve 
 K and then the separate exhaust valve.' The 
 small valve ^relieves the pressure more gradually 
 than if the larger valve were opened at once. 
 As soon as the separate exhaust valve is opened 
 the pressure in the receiver escapes through it 
 and becomes so low that the intercepting valve is 
 again forced to the right (as in Fig. 143) against 
 its seat F by the steam pressure from chamber 
 E, and the engine works simple as in starting. 
 
 To Start as an Automatic Compound. If the 
 separate exhaust valve is left closed, as in Fig. 
 145, the engine will start as an automatic com- 
 pound when the throttle is opened, for the 
 pressure from chamber E will force the intercept- 
 ing valve to the right, as in Fig. 143, thus admit- 
 ting live steam through the reducing valve and 
 ports G to the low-pressure cylinder, while at the 
 same time the high-pressure cylinder exhausts 
 into a closed receiver for a few strokes. This 
 pressure, accumulating in the receiver, will then 
 automatically close the ports G by moving the 
 intercepting valve to the left, as in Fig. 145, and 
 the engine thereafter runs compound. 
 
 Accidents to Schenectady Compounds the Auto- 
 matic Compound of 1892. What should be done 
 
80 ENGINEERS' AND FIREMEN' X MANUAL. 
 
 in case of a break-down on the road, necessi- 
 tating the disconnecting of the high-pressure 
 side? If but a short distance to go and a slow 
 speed would suffice, clamp the high-pressure 
 slide valve in center and permit the engine to 
 run by the admission of live steam through 
 the small pipe *S Yl and the poppet valve N to the 
 high-pressure cylinder (Figs. 133 and 134). If 
 the intercepting valve is out of order, block the 
 poppet valve ^\ T open, that is, up. If it were re- 
 quired to run at considerable speed, this small 
 pipe S l would give insufficient supply, in which 
 case the high-pressure slide valve should be 
 blocked clear back (much farther than its ordi- 
 nary travel carries it), so as to uncover the 
 exhaust port, thus admitting live steam direct 
 to the receiver. If the steam chest is large 
 enough to place the high-pressure valve as 
 described, and the intercepting valve is not de- 
 ranged, the engine would run at full speed with 
 the low-pressure side. If out of order, the inter- 
 cepting valve should be held open (in the position 
 as shown in Fig. 133) by clamping the stem be- 
 tween the stuffing boxes. In all cases the throttle 
 should be handled easily to prevent a too rapid 
 flow of boiler pressure to the large low-pressure 
 cylinder and the consequent liability of jerking 
 the train or causing damage to this cylinder. 
 
 What should be done if it becomes necessary 
 to take down the low-pressure side of the engine? 
 The engine could be moved a short distance with 
 the cylinder cocks open or the indicator plugs re- 
 moved on the high-pressure side, but as most en- 
 
OPERATION OF COMPOUND LOCOMOTI VES. 81 
 
 gines of this class have either a large steam chest 
 or an "Allen"* ported slide valve, the valve can 
 be clamped back far enough to uncover the low- 
 pressure exhaust port, and thus run at full speed. 
 If this cannot be done, block both the low-press- 
 ure crosshead and valve clear back and unscrew 
 the relief valves or take off the front cylinder 
 head on that side to make an exhaust opening 
 from the receiver. If the intercepting valve is 
 out of order, it must be securely clamped -open, 
 as in Fig. 133, otherwise the opening between 
 the receiver and the low-pressure steam chest 
 would be closed. 
 
 In this last procedure, with the exhaust other 
 than through the stack, would the engine steam 
 with much of a train? No; but a limited amount 
 of steam could be maintained by the use of the 
 blower for creating draught. 
 
 What would be the effect of the removal of the 
 slide valve on the disabled side? This would 
 give a free port opening under all circumstances, 
 but would generally consume too much time to 
 be practicable. 
 
 What prevents the leakage of live steam into 
 the receiver when the intercepting valve is closed, 
 as in Fig. 134, there being no packing rings in the 
 two pistons 6r6r? The live steam pressure acts 
 from below when starting, so as to hold these 
 pistons tight against ports of the receiver. Fig. 
 135 illustrates this clearly, if the intercepting 
 
 *See illustrations in Part First of the Manual, showing the 
 'Allen" slide valve. 
 
&2 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 valve were there shown closed, as live steam 
 would then be below pistons GG. 
 
 What would be the result if the wiper L would 
 strike the poppet valve N (Figs. 133 and 134) 
 before the intercepting valve pistons GG closed 
 their ports? Live steam would blow through to 
 the receiver and produce a back pressure on the 
 high-pressure side. 
 
 How can this be prevented? Pistons GG have 
 sufficient lap to allow of their closing before the 
 wiper L strikes the poppet valve N, and the 
 adjustable tappet on the intercepting valve stem 
 should be set so as to cause this. If the tappet is 
 set too far back, valve N would not be opened at 
 all and, as a consequence, no live steam would be 
 admitted to the low-pressure cylinder in starting. 
 
 If the operating piston H should break, what 
 position would the intercepting valve probably 
 take ? On account of the unbalanced area of the 
 stem, it would probably move open to the left 
 as for compound working, Fig. 133. 
 
 Accidents to Schenectady design of 1892, with 
 Southern Pacific Modifications. If it became 
 necessary to disconnect the high-pressure side of 
 the engine, what should be done? The same as 
 with the 1892 Schenectady system. 
 
 Would there be any difference in case the low- 
 pressure side broke down? Yes; disconnect the 
 broken side as usual (see instructions for simple 
 engines in Part First of the Manual) and run with 
 reverse lever in full gear, if for a short distance or 
 a low speed only is required. If it is necessary to 
 run for a considerable distance at a good speed, it 
 
OPERATION OF COMPOUND LOCOMOTIVES. 83 
 
 would be advisable to disconnect the separate ex- 
 haust valve levers from their connection to the 
 reach-rod and properly secure them in either ex- 
 treme position, so as to hold the valve open. The 
 engine can then be "hooked-up," that is, the re- 
 verse lever pulled up toward its central position, 
 to correspond to the demands of the service. 
 
 Accidents to Schenectady Compounds design of 
 1896. What should be done in case the high- 
 pressure side had to be disconnected ? Ordinari] y , 
 open the separate exhaust valve * and do nothing- 
 different than with a simple engine; but to obtain 
 greater speed than the supply of live steam to 
 the low-pressure cylinder through its small steam 
 pipe would permit, the high-pressure valve should 
 be secured in such a position, if possible, as will 
 uncover its exhaust port, thereby admitting live 
 steam to the receiver and thence to the low- 
 pressure cylinder. In this case leave the separate 
 exhaust valve closed and handle the throttle 
 easily so as not to cause constant opening of the 
 safety valves on the low-pressure side. 
 
 What is necessary with the low-pressure side 
 disconnected? Open the separate exhaust valve 
 and allow the high-pressure cylinder to exhaust 
 to the stack through its connection. While con- 
 siderable train could thus be handled, it would 
 not be done at anything but a slow speed, unless 
 the low-pressure slide valve were placed so as to 
 
 * While not absolutely necessary to open the separate exhaust 
 valve for this case, it is best to do so that there may be no 
 accumulation of pressure in the receiver should the high-pressure 
 valve leak. 
 
84 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 uncover its exhaust port and the separate ex- 
 haust valve left closed. 
 
 What is done to prevent full boiler pressure 
 from reaching the low-pressure cylinder in case 
 the reducing valve becomes defective or broken? 
 Pop or safety valves are placed on the chest and 
 both heads of the low-pressure cylinder and they 
 are set at about one hundred pounds, the highest 
 pressure deemed advisable in so large a cylinder. 
 
 In case of a broken intercepting valve what 
 precautions should be taken? Run the, engine 
 compound only and do not stop the engine with 
 the low-pressure side on center. 
 
 Why must the oil dash-pot be kept filled with 
 oil? The flow of oil from one side of the dash- 
 pot piston to the other prevents sudden move- 
 ments of and serious jars to the intercepting valve. 
 
 How can the rapidity of this movement be reg- 
 ulated? By a greater or less opening of the valve 
 P, Figs. 143 and 144, as this valve regulates the 
 flow of oil from one side of the dash-pot piston to 
 the other. A slight opening causes a slow move- 
 ment, while a wide opening makes possible a too 
 rapid movement. 
 
 What would be most liable to cause breakage 
 to the intercepting valve ? Allowing the oil dash- 
 pot to become partially or wholly empty. 
 
 What kind of oil should be used in this dash- 
 pot? Only mineral oil, thinner, if anything, than 
 ordinary engine oil. 
 
 What is the purpose of the key shown in the 
 dash-pot (Fig. 144)? To prevent the intercepting 
 valve from turning around. 
 
OPERATION OF COMPOUND LOCOMOTI VES, 85 
 
 With this compound, what pressure from the 
 cab is used to operate the separate exhaust valve ? 
 Either air or steam. 
 
 Why is air pressure generally considered pref- 
 erable? On account of the absence of moisture 
 therein. As the separate exhaust valve piston J 
 and its cylinder (Figs. 143 and 145) project from 
 the front of the cylinder saddle and are exposed to 
 currents of cold air, the use of steam therein and a 
 lack of proper drainage might cause them to freeze 
 in cold weather. 
 
 What objection is there to the use of air? 
 Should the air pump stop or the pressure other- 
 wise become exhausted, as in switching and pick- 
 ing up a large number of air-brake cars, there 
 might be insufficient pressure to hold the valve 
 open against the receiver pressure. 
 
 How is this objection overcome when air is 
 used for this purpose? Besides the air connec- 
 tion to the three-way cock in the cab, there is a 
 steam connection; closing the one and opening 
 the other, quickly furnishes an alternative press- 
 ure for operation. 
 
 What would be the result if both the steam and 
 the air connections were left open ? There would 
 be no effect upon the engine itself, but the steam 
 would fill the whole air-brake system with w T ater 
 and seriously affect the operation of the brakes. 
 
THE PITTSBURG COMPOUND. 
 
 The Pittsburg Locomotive Works have been 
 one of the largest builders of two-cylinder or 
 cross-compound locomotives in this country. 
 Their location of the intercepting valve in the 
 saddle of the high-pressure cylinder instead of 
 the low-pressure cylinder is an arrangement 
 which obviates the necessity of a second steam 
 pipe for admitting live steam to the intercepting 
 valve and low-pressure cylinder when it is de- 
 sired to work the engine non-compound. 
 
 With the valve mechanism which will be 
 shown and described in what follows, when the 
 reverse lever is either in full forward or back-up 
 gear and the throttle opened, the engine starts 
 by the admission of live steam into both cylin- 
 ders and with an open exhaust passage from each 
 cylinder to the stack. The live steam admitted 
 to the low-pressure cylinder is sufficiently re- 
 duced in pressure by passing through a reducing 
 valve to cause the engine to have the same power 
 that a simple locomotive would have with two 
 cylinders the size of the high-pressure cylinder. 
 When the reverse lever is " hooked-up," or drawn 
 toward the center, one or more notches, it me- 
 chanically works an operating valve and piston 
 near the cab, which throws the intercepting 
 valve into position for compound working. 
 There is a hand lever in the cab, as shown in 
 Fig. 148, which can be used to move the inter- 
 
 (86) 
 
OPERATION OF COMPOUND LOCOMOTIVES. 87 
 
88 ENGINEERS' ;\ND FIREMEN'S MANUAL. 
 
 cepting valve in case of derangement of the op- 
 erating device, or other necessity. However, 
 the engine will only start simple when the in- 
 tercepting valve is placed in proper position, as 
 this valve does not automatically assume simple 
 position of its own volition. Fig. 148 gives the 
 
 Yi0rz of z/afoes w/Zex 
 
 general arrangement and shows the position of 
 the intercepting and reducing valves in the 
 saddle of the high-pressure cylinder on the right- 
 hand side of the engine, the lever connections be- 
 tween the intercepting valve and the operating 
 cylinder near the cab, and the means of moving 
 
OPERATION OF COMPOUND LOCOMOTIVES. 
 
 89 
 
 the operating valve by its attachment to the 
 reach-rod. The operating piston can be actuated 
 either by air or steam pressure, the former being 
 preferable, especially in cold climates. 
 
 Figs. 149 and 150 show on a larger scale the 
 same section through the valves in the saddle. 
 
 In Fig. 149 the intercepting and the reducing 
 valves are in position for working simple, while 
 in Fig. 150 they are shown in compound position. 
 Port S is the passage from the steam pipe to the 
 high-pressure steam chest, and port E the ex- 
 haust passage from the high-pressure cylinder; 
 port.R is the opening into the receiver; port B 
 leads to the atmosphere through the stack, being 
 
90 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 an independent exhaust for the high-pressure cyl- 
 inder. Port C is a branch from the main steam 
 port S, and carries live steam to the reducing valve 
 & for use in the low-pressure cylinder when 
 needed. 
 
 When the intercepting valve is moved to the 
 left in position for working simple, as shown in 
 Fig. 149, steam from the high-pressure exhaust^ 1 
 passes through the intercepting valve (between 
 its two piston ends) and to the atmosphere 
 through the independent exhaust B. At the same 
 time live steam from C opens the reducing valve 
 6r, as the valve is then unbalanced by its left end 
 being larger than its right, and passes through the 
 intercepting valve chamber D and the receiver E 
 to the low-pressure cylinder. The engine is thus 
 made a simple engine with live steam admission 
 and independent exhausts for each cylinder, as 
 indicated by the arrows in Fig. 149. 
 
 The reducing valve 6r, when in use, only allows 
 a portion of the full pressure to pass into the 
 receiver, for, when the pressure in the intercepting 
 valve chamber D (Fig. 149) becomes equal to 
 about half that of the boiler, it acts against the 
 larger left-hand end of the reducing valve and 
 forces it closed to the right thereby throttling 
 the steam. 
 
 The intercepting valve moved ahead, or in com- > 
 pound position, as in Fig. 150, holds closed the 
 reducing valve G, thus shutting off the live steam 
 supply to the low-pressure cylinder. At the same 
 time it closes the independent exhaust opening B, 
 instead opening the ports to the receiver R and con- 
 
OPERATION OF COMPOUND LOCOMOTI VES. 9 1 
 
 necting the high-pressure exhaust E therewith 
 around the stem of the intercepting valve. As the 
 other end of the receiver leads to the low-pressure 
 steam chest, the high-pressure exhaust thus be- 
 comes the supply steam for the low-pressure cyl- 
 inder and the engine works as a compound, the 
 flow being indicated by the arrows, Fig. 150. 
 
 From the above description it will be observed 
 that the office of the intercepting valve is to convert 
 the locomotive from simple to compound, or the 
 reverse. The duty of the reducing valve is, when 
 the engine is working single-expansion, to reduce 
 the live steam from the boiler to a pressure in- 
 versely proportional to the ratios of the two cyl- 
 inders before delivering it to the receiver and low- 
 pressure cylinder, thus making the crosshead loads 
 equal on each side of the engine. 
 
 Accidents to Pittsburg Compounds. If the engine 
 broke down and it became necessary to disconnect 
 either side, could the engine be run successfully 
 on one side? Yes, it would be more powerful than 
 a simple engine under similar circumstances and 
 could develop good speed, inasmuch as the inde- 
 pendent exhaust ports B (Fig. 149) are of con- 
 siderable size. 
 
 With the high-pressure side disconnected, how 
 should the engine be run? The intercepting 
 valve should be placed in simple position (as in 
 Fig. 149) by leaving the reverse lever in full 
 gear. Live steam would then pass through the 
 reducing valve to the low-pressure cylinder and 
 exhaust in the usual way. The high-pressure 
 valve should, of course, be clamped in the center. 
 
92 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 If the low-pressure side were disconnected, 
 how conld the engine be run? Clamp the low- 
 pressure valve in the center so as to cover all 
 ports and work simple, with engine in full gear. 
 Steam would then be admitted as usual through 
 the steam pipe to the high-pressure cylinder and 
 exhausted through the intercepting valve cavity 
 and the independent exhaust jB, Fig. 149. 
 
 In both of these cases what would be necessary 
 in order to run at considerable speed? To close 
 the small valve which supplies steam to the op- 
 erating device. The hand lever can then be 
 used for operating and thus the reverse lever 
 hooked up to a shorter cut-off. The intercepting 
 valve levers should be securely fastened in 
 simple position. 
 
 With a demolished steam chest on the low- 
 pressure side, could the engine be fixed to run in 
 any way different from such an accident to a 
 simple locomotive? Yes. Proceed the same as 
 before described when the lo\v-pressure side is 
 disconnected, except that the reducing valve must 
 now be held closed. This could be done by tight- 
 ening up the nuts on the outside stem of the 
 reducing valve, or by inserting washers or a block 
 under them. This same procedure could be fol- 
 lowed for broken valve yoke, or valve stem bro- 
 ken off inside of steam chest, under which 
 circumstances it is difficult to cover ports with- 
 out taking up the steam chest cover. 
 
 What should be done if the reducing valve 
 became broken? Endeavor to start compound, 
 that is, with the lever hooked up three or four 
 
OPERATION OF COMPOUND LOCOMOTIVES. 93 
 
 notches, but if necessary to run simple, use very 
 light throttle or reduce the amount of boiler 
 pressure carried. 
 
 If the packing rings in the intercepting valve 
 blew badly, how could it be detected? First see 
 that the slide valves are tight, then shut off the 
 supply of air or steam from the operating cylin- 
 der by closing the small globe valve in the cab, 
 pull the intercepting valve clear back (by means 
 of the hand operating lever) into simple position, 
 as in Fig. 149, and open the throttle, still leaving 
 the valves in the center. The blow would show 
 in the stack. However, it is an easy matter to 
 remove the intercepting valve, by taking off the 
 back cap, and examine the packing rings, and 
 this should be done frequently, that no broken 
 pieces may catch in the ports. 
 
 With this design of compound, is it necessary 
 to caution the engineer against the bad practice 
 of operating the engine in simple position for 
 too great a length of time, or at high speeds ? 
 No; for, if the small valve in the cab which sup- 
 plies pressure to the operating device be open, 
 to run the engine simple, requires that the reverse 
 lever be at full stroke, and no competent man 
 would work the engine thus longer than neces- 
 sary. 
 
 In starting, where should the reverse lever be 
 placed? In full motion to allow the intercepting 
 valve to close and the reducing valve to open 
 and admit live steam to the low-pressure 
 cylinder. 
 
RICHMOND COMPOUND. 
 
 The Richmond compound locomotive (some- 
 times termed the "Mellin" system, as it is built 
 under those patents) is also of the two-cylinder or 
 cross-compound type and belongs to the class of 
 
 convertible compounds. The large low-pressure 
 cylinder is placed on the right-hand side of the 
 engine, and within its saddle, as shown in Fig. 151, 
 is located the special valve mechanism by which 
 
 (94) 
 
OPERATION OF COMPOUND LOCOMOTl YES. 95 
 
 the engine starts with the admission of live steam 
 to both cylinders and thereafter automatically 
 changes to compound, or may be converted back to 
 simple any time at the will of the engineer. With- 
 out any movement of valves by the engineer, the 
 locomotive is an "automatic" compound, that is, 
 changes to working compound after the first stroke 
 or two; but the movement by him of a three-way 
 cock in the cab, causes the opening of a separate 
 exhaust valve (sometimes called the "emergency 
 valve") for the high-pressure cylinder, and thus 
 the engine can be run simple as long as he thinks it 
 advisable, or, if disabled, can be brought in with 
 one side like a single-expansion locomotive. 
 
 The device called the intercepting valve really 
 consists of three separate and distinct valves, as 
 shown in Figs. 152 and 153. 
 
 The intercepting valve proper is marked G and 
 is a double poppet valve with its two seats of un- 
 equal areas, and has a stem extending back and 
 connecting with the piston P of an air dash-pot. 
 The intercepting valve moved, or opened, as in 
 Fig. 153, connects the receiver R with the low- 
 pressure steam-chest port L, while if closed, as in 
 Fig. 152, it cuts off this communication and opens 
 the receiver R to the cavity U. 
 
 The reducing valve is a long annular valve sur- 
 rounding the intercepting valve stem and closes 
 by moving to the left. When open, it admits live 
 steam from chamber S to the low-pressure steam 
 chest cavity L; when closed, it cuts off this com- 
 munication. 
 
 The separate exhaust or "emergency" valve E is 
 
96 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 an ordinary bevel-seated wing-valve with its right- 
 hand end in the forni of a piston. Steam pressure 
 from a three-way cock in the cab, if admitted 
 against this piston, forces the separate exhaust 
 valve open, thereby connecting the cavity U with 
 the main exhaust cavity C; without pressure on 
 this piston, the spring F again seats the valve. 
 
 JStig 
 
 The reducing valve is shown heavily cross-sec- 
 tioned, the intercepting valve is next as dark. 
 
 The operation of the valves is as follows: Sup- 
 pose the engine to be at rest after running com- 
 pound with the valves in position as shown in 
 Fig. 153. Upon opening the engine throttle, steam 
 passes not only to the high-pressure side in the 
 
OPERATION OF COMPOUND LOCOMOTIVES. 
 
 97 
 
 usual manner, but also through a branch steam 
 pipe S (Fig. 151) to the annular cavity S3 (Fig. 
 153), bears against the shoulder e of the reduc- 
 ing valve at the seat B (Figs. 153 and 154) and 
 forces the latter valve to the right, and with it the 
 intercepting valve, to the position in which they 
 are shown in Fig. 152. As soon as the enlarged 
 end of the reducing valve passes the edge h of the 
 
 from 
 
 port L (see also Fig. 154), live steam is admitted 
 to L and thence to the low-pressure cylinder, as in- 
 dicated by the arrows. As we assumed the engi- 
 neer had not opened the separate exhaust valve, it 
 will remain closed instead of open, as Fig. 152 shows 
 it; otherwise that figure would show the valve posi- 
 tions at this stage. Thus, while the receiver R is in 
 
98 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 communication with the cavity f7, there is no 
 outlet from the latter, and one or two exhausts 
 from the high-pressure cylinder into the closed 
 receiver R will produce sufficient pressure to act 
 against the larger left-hand face of the inter- 
 cepting valve G and cause it to move to the left, 
 shoving with it and closing the reducing valve, 
 as shown in Fig. 153. Now the receiver pressure 
 becomes the supply for the low-pressure cylinder 
 as shown by the arrows, and the engine works 
 compound thereafter. The engine will start all 
 ordinary trains in this manner but if the train 
 
 to be started is a very heavy one, or such a train 
 is threatened with stalling while ascending a 
 heavy grade, the handle of the three-way cock 
 in the cab should be turned to open the separate 
 exhaust valve E. This would vent the pressure 
 in chamber U to the main exhaust C, as indicated 
 by the arrows in Fig. 152. If the engine were 
 starting, no pressure could accumulate in the re- 
 ceiver R on account of this vent to the atmosphere, 
 and hence all valves would remain as in Fig. 152 
 and the engine would continue to work simple 
 until such time as the engineer closed the separate 
 
OPERATION OF COMPOrXD LOCOMOTIVES. 
 
 99 
 
 exhaust valve E by means of his cab valve. If, 
 however, the engine were stalling working com- 
 pound (Fig. 153) and the engineer opened the 
 
 . sss. 
 
 separate exhaust valve E, the removal of press- 
 ure from chamber U would cause the intercepting 
 valve to close, assisted by the live steam pressure 
 on the reducing valve shoulder, and thus all valves 
 
 T/te J?icm0Ke? Compound. 
 
 would remain as in Fig. 152 until the engineer 
 desired to work compound again. Then he 
 would simply close the separate exhaust valve E 
 
100 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 and permit the valves to automatically assume 
 compound working by the accumulation of press- 
 ure in the receiver R. 
 
 The annular shaped reducing valve appears so 
 much like an inoperative sleeve around the in- 
 tercepting valve stem that the separate sketch is 
 made on a larger scale in Fig. 154, in order to illus- 
 trate its principle the more clearly. Live steam 
 from S bearing against the shoulder e would force 
 the reducing valve from the position in the cut to 
 the right until shoulder e had passed the edge h 
 of the chamber L and live steam thus be admitted 
 to L and the low-pressure cylinder. As soon as 
 the pressure in L became sufficiently great, say 
 about half that in S, the valve would close 
 partly so that only the desired proportion of the 
 full boiler pressure would be admitted to the 
 low-pressure cylinder. 
 
 The injurious action of large pistons in pump- 
 ing air when the engines are shut off, as previously 
 mentioned under "Classes of Compound Locomo- 
 tives and their General Construction," is prevented 
 in compound engines of the Richmond type by 
 the use of "by-pass" valves located in the casting 
 of low-pressure cylinder, as shown in Fig. 151, 
 and further shown in detail in their two positions 
 by Figs. 155 and 156. They work automatically 
 by the opening and closing of the engine throttle, 
 their construction and operation being as follows: 
 The outer ends of the two piston valves W are 
 connected by the passages AA with the induction 
 ports of the low-pressure cylinder and their inner 
 ends are connected by the passages 00 with the 
 
OPERATION OF COMPOUND LOCOMOTIVES. 101 
 
 steam ports. The pistons PP simply act in the 
 cavities of the valves as dash-pots to prevent slam- 
 ming of the valves. 
 
 Open the engine throttle, and live steam from 
 the induction ports through the passages AA 
 drives the valves W toward each other against 
 their seats and communication between -the 
 two steam ports and is closed, as in Fig. 156. 
 With the throttle closed, the least vacuum in the 
 
 steam chest, acting at A A, is aided by compression 
 in the cylinder through ports 00, and the "by- 
 pass" valves move outward to the position shown 
 in Fig. 155. In this position the two steam ports 
 00 are connected and air passes freely from one 
 side of the piston to the other the purpose for 
 which they are applied. 
 
 The necessity for very large port openings for 
 the large low-pressure cylinders was mentioned 
 under the general discussion of compound loco- 
 
102 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 motives and it was there stated that auxiliary 
 ported valves of the "Allen" type were used to 
 give a double port opening to the cylinders in the 
 early part of the admission period. 
 
 One Richmond design of slide valve employs 
 this auxiliary port not only for double early ad- 
 mission, but also to give a double opening in the 
 early exhaust period. Fig. 157 shows the design 
 and gives the dimensions. It will be noticed that 
 
 the "Allen," or supplementary, port is much wider 
 at the seat than usual.* 
 
 To clearly show the features of novelty in this 
 valve over the ordinary slide valve, Figs. 158 and 
 159 are given. The arrows in Fig. 1 58 indicate the 
 double exhaust from the right-hand end of the 
 cylinder during the early exhaust period. In Fig. 
 159 the arrows indicate similarly the ordinary 
 
 ^Letters patent have been granted for this valve. 
 
OPERATION OF COMPOUND LOCOMOTIVES. 1 03 
 
 action of an "Allen" ported valve in giving double 
 admission to the same end of the cylinder during 
 the early steam period. This style of slide valve 
 has been in use on locomotives and given only a 
 six-inch extreme travel of valve and has proven 
 very successful in keeping down the back press- 
 ure, especially at high speeds. 
 
 Accidents to Richmond Compounds. In case of 
 accident on the road requiring the engine to be 
 run in with one cylinder, what should be done? 
 Ordinarily, open the separate exhaust or "emerg- 
 ency" valve and do nothing otherwise differently 
 than with a simple engine. 
 
 In case the engine was running with the low- 
 pressure side only, why do you instruct to open 
 the separate exhaust valve? So that there shall 
 be no accumulation of pressure in the receiver 
 which might occur in case of a leaky slide valve 
 or balance strips leaking on the high-pressure 
 side. 
 
104 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 As the emergency port openings are small, what 
 could be done in order to obtain considerable 
 speed in case the break-down occurred in passen- 
 ger service? Try to block the slide valve on the 
 disabled side in an extreme position so as to un- 
 cover the exhaust port. 
 
 What should be done in case the reducing 
 valve stuck open or became broken? Care should 
 be used in starting by opening the throttle very 
 
 slightly and the engine should be run as a com- 
 pound only. If it had to be run simple, the 
 boiler pressure should be reduced about one-half. 
 
 What might cause the reducing valve to stick ? 
 Feeding valve oil to the low-pressure side when 
 the engine is working compound and there is 
 consequently no flow of steam through this 
 valve. 
 
 What precaution would it be advisable to ob- 
 serve in case the intercepting valve became 
 broken? The engine should be run compound 
 
OPERATION OF COMPOUND LOCOMOTIVES. 1 05 
 
 only and it would be safer not to stop with the 
 low-pressure side on center. If this latter pre- 
 caution were not observed, the high-pressure 
 piston might have considerable back pressure 
 upon it from the receiver, should the intercepting 
 valve break in such a way as to permit live steam 
 from the reducing valve to enter the receiver in 
 starting. 
 
 What prevents slamming of the intercepting 
 valve? The air dash-pot connected thereto. 
 
 In this class of compounds, why are the cylinder 
 neads sometimes dished, or not flat, as is usually 
 the case? In order to give a maximum strength 
 with a minimum weight of piston, these builders 
 frequently use a piston such as is shown in Fig. 
 160; hence the cylinder heads conform to the 
 shape of the piston. 
 
ROGERS COMPOUND. 
 
 The intercepting valve originally employed by 
 the Rogers Locomotive Works for their system of' 
 two-cylinder compound, was placed in the smoke- 
 box and was controlled automatically and be- 
 yond the will of the engineer. In starting, by 
 placing the reverse lever in either extreme posi- 
 tion, a separate reach-rod with suitable levers 
 was made to open the reducing valve and admit 
 live steam from the boiler to the low-pressure 
 cylinder, and close communication between the 
 latter and the receiver, so that the high-pressure 
 cylinder exhausted into a closed reservoir or re- 
 ceiver. After one or two strokes sufficient pressure 
 accumulated in the receiver to automatically 
 throw the intercepting valve into position for 
 working compound and the hooking up of the 
 reverse lever closed the reducing valve. 
 
 The succeeding arrangement used by these 
 builders is fully described and illustrated in what 
 follows. The device is for a two-cylinder or cross- 
 compound locomotive, and is placed in the high- 
 pressure saddle on the right side and connected 
 to a lever in the cab having three notches, and is 
 operated by the engineer at will. As long as 
 this lever remains in the forward notch the en- 
 gine works as a single expansion locomotive; 
 the back notch places the intercepting valve in 
 compound position, while the middle notch 
 makes an automatic compound, that is, the inter- 
 
 (106) 
 
OPERATION OF COMPOUND LOCOMOTI VES. 107 
 
 cepting valve works the engine simple for a few 
 strokes and then the valves automatically assume 
 the compound position. Thus this engine be- 
 longs to the class of convertible compounds. 
 
 The component parts of the device are: A reg- 
 ulating valve (positively controlled by the cab 
 
 lever above mentioned), an intercepting and a re- 
 ducing valve (controlled either positively by the 
 regulating valve or at times automatically by the 
 pressure in the receiver), and a separate exhaust 
 valve (controlled by the operating valve). The 
 
108 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
OPERATION OF COMPOUND LOCOMOTI VES. 109 
 
1 1 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 intercepting valve has two positions, one for work- 
 ing compound and one for working simple. In 
 the former position, as shown in Fig. 163, the high- 
 pressure cylinder exhaust is connected to the re- 
 ceiver and thence to the low-pressure side, while 
 in the simple position, as shown in Fig. 162, this 
 communication is closed and the high-pressure 
 exhaust directed through the separate exhaust 
 valve to the stack, live steam at the same time 
 being admitted to the low-pressure steam chest 
 through the reducing and the intercepting valves. 
 
 To somewhat reduce the high compression that 
 takes place in the large low-pressure cylinder 
 when running at high speeds without steam as, 
 for instance, down grades a by-pass arrangement 
 similar in some respects to "La Chatalier" brake is 
 employed. This consists of an automatic device 
 for connecting the two sides of the low-pressure 
 piston when steam is shut off, and will be fully 
 described hereafter. 
 
 Fig. 161 is a view from the front, showing the 
 high-pressure cylinder to be on the right-hand 
 side of the engine. In the saddle on that side 
 are shown the positions of the regulating valve 
 and the intercepting and separate exhaust valves. 
 The location of the by-pass valve on the low- 
 pressure cylinder is also shown. 
 
 Figs. 162 and 163 are sectional views of the 
 special valve mechanism. For simplicity in ex- 
 plaining their working, the regulating valve is 
 shown as though it were located directly under- 
 neath the intercepting valve which is not its actual 
 position shown in Fig. 161. The intercepting 
 
OPERATION OF COMPOUND LOCOMOTI VE1S. Ill 
 
 valve is composed of two parts bolted together 
 and is shown cross-sectioned more heavily than 
 its casing while the reducing valve L within it is 
 distinguishable by its still darker appearance. Its 
 principal port openings to the receiver and from 
 the high-pressure cylinder exhaust are lettered 
 and the direction of flow through them is indicated 
 by arrows, that an understanding may be the more 
 easily arrived at. Port G is an annular chamber 
 around the intercepting valve cylinder H and is 
 connected with the high-pressure steam pipe in the 
 saddle and therefore has live steam pressure when 
 the engine throttle is open. Between G and the in- 
 tercepting valve is a series of holes marked J. 
 The intercepting valve is hollow and has two se- 
 ries of holes through its shell at P and Q, the 
 latter being to the right of the reducing valve seat. 
 Fig. 162 shows the intercepting valve closed (to 
 the right) on its seat A, and the reducing valve 
 off its seat (open), as it is when working simple 
 except that the reducing valve L is then brought 
 near enough to its seat to the left, to prevent 
 more than about one-half the boiler pressure from 
 passing through it. As usual, the reducing is 
 accomplished by the two ends of the reducing 
 valve L being of different diameters, the smaller 
 end having its outer left-hand side always con- 
 nected to the atmosphere through small ports 
 marked N and ; while the outside of the larger 
 right-hand end is exposed to the receiver press- 
 ure when in operation, as in Fig. 162. The left- 
 hand smaller end M of the intercepting valve 
 works in a cylinder W, while the right-hand 
 
112 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 larger area of the intercepting valve is exposed 
 either to the receiver or the high-pressure exhaust 
 cavity, according to the position of the valve. 
 The separate exhaust valve is located in a cham- 
 ber U directly connected to the main exhaust 
 pipe Z. (See Figs. 161 and 163.) The right- 
 hand end of the separate exhaust valve is in the 
 form of a piston and works in a cylinder T. The 
 outer ends of these two cylinders, W and T, are 
 connected by small pipes C and D with the regu- 
 lating valve, as shown in Figs. 162 and 163. The 
 stem of the intercepting valve extends over into 
 separate exhaust valve and forms a guide to 
 keep both valves central, and also serves as a 
 dash-pot, but allows each valve to act independ- 
 ently of the other. All pistons are fitted with 
 packing rings, as shown, and the valve seats and 
 ground joints are so indicated. 
 
 The regulating valve receives steam from G 
 through a small port X and therefore has live 
 steam whenever the engine throttle is open. The 
 regulating valve consists of a slide valve of the 
 well-known "D" type and moves on a seat having 
 two steam ports and one exhaust opening, as 
 usual with a slide valve. Steam admitted through 
 the right steam port and pipes DD to chamber T 
 would bear against the separate exhaust valve and 
 close it, as in Fig. 163. Steam through the left 
 port and pipes CC to chamber W would force the 
 intercepting closed, as in Fig. 162. If the engi- 
 neer places the regulating valve lever in the 
 forward notch, as in Fig. 162, live steam entering 
 the regulating valve chamber from ports G and X 
 
OP K 11 AT ION OF COMPOUND LOCOMOTI VEX. 1 13 
 
 finds the left hand port uncovered and passes 
 through the small pipe CC to the cylinder W (as 
 indicated by arrows), moving the intercepting 
 valve to the right against its seat A and thereby 
 closing communication between the high-pressure 
 cylinder exhaust port and the receiver R. In 
 this position live steam pressure from G passes 
 through ports JJ and PP to the interior of the 
 intercepting valve, automatically opening the 
 reducing valve and flowing through ports QQ, 
 enters the receiver jR, the other end of which 
 is connected to the low-pressure steam chest, 
 as shown in Fig. 161. Thus the low-pressure 
 cylinder has received live steam at a reduced 
 pressure and can work independently of the high- 
 pressure cylinder, as its exhaust is as always to 
 the stack. The intercepting valve now being- 
 closed, the exhaust from the high-pressure cyl- 
 inder (its communication to the receiver being 
 thereby shut off) forces the separate exhaust valve 
 off its seat, as in Fig. 162, and escapes to the stack 
 and the engine works simple, or with a live 
 steam admission and an exhaust to the atmos- 
 phere on both sides. The separate exhaust valve 
 remains open, as shown in Fig. 162, because 
 chamber T is connected to the atmosphere 
 through pipe DD, the under side of the regulat- 
 ing slide valve, and pipe E as indicated by ar- 
 rows. 
 
 If the regulating lever in the cab be moved to 
 the back notch, the regulating valve takes the 
 position shown in Fig. 163 and will then admit 
 steam through the right-hand pipe DD, into 
 
1 1 4 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 chamber T, pushing and holding the separate ex- 
 haust valve against its seat B, and at the same 
 time chamber Trwill be in exhaust through pipes 
 CC and E, as indicated by arrows. The separate 
 exhaust valve being now closed, a slight pressure 
 in the cavity marked ' 'high-pressure cylinder 
 exhaust" will open the intercepting valve, that is, 
 move it off its seat A into the position shown in 
 Fig. 163. Then the high-pressure cylinder ex- 
 hausts through the intercepting valve into the 
 receiver and thence to the low-pressure steam 
 
 Compound 
 
 fosifton 
 
 chest, and the engine works compound. No live 
 steam from ports GG can get to the receiver in 
 this position as the ports PP are not in register 
 with those at JJ. 
 
 It will be noticed that there is an extended flange 
 on the face of the intercepting valve, that enters the 
 seat of the latter enough before closing and leaves 
 it sufficiently late in opening, to prevent live 
 steam from flowing through ports PP, QQ, and R 
 to the high-pressure cylinder exhaust port when 
 
OPERATION OF COMPOUND LOCOMOTI YES. 115 
 
 the intercepting valve is opening or closing. If 
 the engine is standing and the regulating valve 
 is moved to its central position, as shown in Fig. 
 164, when the throttle is opened steam will pass 
 through both pipes CC and DD to the outer ends 
 of the intercepting and the separate exhaust valves 
 respectively, and they will both be instantly 
 closed against their respective seats A and B, 
 Figs. 162 and 163. The receiver would then be 
 filled with steam through the hollow intercepting 
 valve and the reducing valve, as indicated by the 
 arrows in Fig. 1 62 ; but as soon as the pressure at the 
 high-pressure exhaust port became about twenty 
 per cent, of the pressure in the dry pipe at the 
 time, the intercepting valve would be opened and 
 thereafter held open by the receiver pressure act- 
 ing toward the left on the large right-hand end 
 of the intercepting valve; thus a slight pressure 
 on the large area of this valve overbalances the 
 higher pressure on the smaller left-hand end M 
 in chamber W, and the engine automatically 
 changes to compound after two or three strokes, 
 the main ports being opened as in Fig. 163. 
 
 If the engine had been working simple, with the 
 valves as in Fig. 162, and the operating valve lever 
 were placed in either the center or back notch, 
 the working would automatically be changed to 
 compound; if in the center notch, it would take a 
 slight accumulation of pressure at the high-press- 
 ure exhaust port, as just explained; if in the back 
 notch the intercepting valve opens with almost no 
 pressure from the high-pressure exhaust port as 
 then chamber IF is in exhaust through pipe CC 
 
116 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 and the regulating valve. Subsequently to work- 
 ing simple, it is best to move the regulating lever 
 to its middle position (Fig. 164) for a few sec- 
 onds without closing the engine throttle; after 
 that it can be moved to its back notch, as in Fig. 
 163, and left there until it is desired to again 
 start simple or go from compound to single-ex- 
 
 . /66. 
 
 r=^. r 
 
 CyZ.JP0rt 
 
 pansion in order to prevent stalling on a heavy 
 grade. 
 
 Figs. 165 and 166 show two views of the by- 
 pass arrangement which is placed on the low-press- 
 ure cylinder in the position shown in Fig. 161. 
 It consists of a valve F which automatically opens 
 
OPERATION OF COMPOUND LOGOMOTI VES. 117 
 
 and closes the port in a hollow casting bolted to 
 the cylinder and connected below the valve seat 
 at K and L with the steam ports of the low-press- 
 ure cylinder, as illustrated in Figs. 165 and 166. 
 The hole through this by-pass casting is two 
 inches in diameter. In Fig. 166 the valve Fis 
 shown dropped down in its chamber, thus leaving 
 a two-inch open communication between the 
 steam ports and hence the two sides of the low- 
 pressure piston. A small pipe from the live steam 
 port in the saddle of the high-pressure cylinder 
 leads through the pipe S to the under side of this 
 cylindrical valve F, as shown, so that when the 
 engine throttle is opened the valve Fraisestothe 
 top of its chamber and shuts off all communica- 
 tion between the ports K and L, remaining there 
 as long as the high-pressure cylinder is receiving 
 steam; but when the throttle is closed, it falls 
 again by gravity and is thus an automatic valve. 
 
 Accidents to Rogers 7 Compounds. In case of 
 break-down on one side of this engine, can 
 it be run in with the other side? Yes. The 
 reducing valve would furnish a live steam 
 supply for the low-pressure cylinder, or the sep- 
 arate exhaust valve would give an exhaust open- 
 ing for the use of the high-pressure cylinder, 
 according to which side was to be used; hence, in 
 either case, general instructions would be to place 
 the regulating valve in its extreme forward posi- 
 tion, as for working simple, Fig. 162. 
 
 Under such circumstances would the engine 
 be as powerful as a simple engine on one side? 
 Yes, considerably more so at low speed, but the 
 
1 1 8 ENGINEERS' AND 'FIREMEN'S MANUAL. 
 
 smaller port openings than usual would not per- 
 mit of as great speed. 
 
 As there are three notches in the cab for the 
 regulating valve lever, how should this be handled 
 when it is desired to change from simple to com- 
 pound, or the reverse? It is not advisable to 
 throw it from forward to back notch, or the oppo- 
 site, without pausing a second or two in the mid- 
 dle notch and thereby producing a more gradual 
 movement and causing a cushioning of the in- 
 tercepting and separate exhaust valves. 
 
 Under ordinary circumstances, in what posi- 
 tion is it best to keep the regulating valve? In 
 the back notch, or compound position. 
 
 How should a light train be started? With 
 the regulating valve lever in the center notch. 
 The engine starts thus as an automatic com- 
 pound. 
 
 If the engine actually works compound in the 
 center position, why is that not advisable? Be- 
 cause in that position the opening and closing of 
 the throttle while running and the wide varia- 
 tions of pressure in the steam pipe and receiver 
 when running, would cause more or less unneces- 
 sary movements of the intercepting valve. 
 
 When running the engine with one side, in 
 what position will the "by-pass" valves (Figs. 
 165 and 166) be found? No matter which side 
 is in use, live steam from the high-pressure 
 steam pipe acts to keep them closed. 
 
 What kind of oil should be used in the oil 
 cups shown in Fig. 162? Nothing but valve oil 
 and that regularly but not too often, as it has a 
 
OPERATION OF COMPOUND LOCOMOTI VES. 1 1 9 
 
 tendency to gum the valves where there is not a 
 constant flow of steam. 
 
 If the high-pressure side were on the center, 
 why would not the engine move with the operat- 
 ing lever in compound position (back notch)? 
 Because then the valves would be as in Fig. 163 
 and no live steam could be admitted to the low- 
 
 pressure cylinder. This would not be the case in 
 starting with the regulating lever in either of 
 the other two notches. 
 
 BROOKS TWO-CYLINDER COMPOUND. 
 
 This design is of the two-cylinder or cross-com- 
 pound type, built under the Player patents, having 
 
120 ENGINEERS' AND FIREMEN'* MANUAL. 
 
 the high-pressure cylinder on the left side and a 
 receiver in the smoke-box between the two cylin- 
 ders, as shown in Fig. 167. 
 
 There is a combined admission, pressure-regu- 
 lating and intercepting valve located either on 
 the receiver in the smoke-box as shown, or in the 
 cylinder saddle, which valve upon opening the 
 engine throttle admits live steam at a reduced 
 pressure to the low-pressure cylinder; at the same 
 time the intercepting valve automatically closes, 
 preventing the live-steam pressure from working 
 against the high-pressure piston. The reducing 
 valve remains open until the pressure in the re- 
 ceiver, accumulating from the high-pressure ex- 
 haust, becomes equal to or slightly greater than 
 that on the low-pressure side, when the valve 
 automatically closes, thereby shutting off the ad- 
 mission of live steam, and the intercepting valve 
 simultaneously opens the receiver to the low- 
 pressure steam chest, and the engine works com- 
 pound thereafter as long as the throttle remains 
 open. 
 
 In order to give the engineer control of the 
 locomotive at all times, controlling valves are 
 provided on the low pressure side. In the illus- 
 tration (Fig. 168) these valves, A and B, are shown 
 located in the bottom of the receiver and are con- 
 nected to the cab by suitable levers C and D. 
 They are sometimes made larger, connected 
 higher up with the exhaust pipe, and arranged 
 as to work automatically in combination with the 
 intercepting valve, so that the engine can be run 
 simple as long as desired and the exhaust take 
 
OPERATION OF COMPOUND LOCOMOTI VES. 121 
 
 TWQ-CYLJNDER COMPOUND, 
 
122 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 place through the stack; however, its builders 
 have claimed the design here shown to be "all that 
 is necessary to give the engine its maximum 
 power." 
 
 The operation of the locomotive is as follows: 
 When the engine throttle is opened, live steam is 
 
 admitted to the high-pressure steam chest through 
 the steam pipe 8 (Figs. 167 and 168) and op- 
 erates upon the high-pressure piston in the usual 
 manner. At the same time, through the small 
 steam pipe L, steam acts against the seat E of 
 the reducing valve, then closed as in Fig. 170, 
 
OPERATION OF COMPOUND LOCOMOTI VEti. 123 
 
 causing this valve to open, passing through the 
 hollow portion of the valve, automatically clos- 
 ing the intercepting valve against its seat F on 
 the receiver, as in Fig. 169. Steam then flows 
 through the passages in the intercepting valve 
 and down to the low-pressure steam chest, as in- 
 
 C&sed, 
 
 dicated by the arrows. To render them readily 
 distinguishable, the reducing or regulating valve 
 is cross-sectioned very heavily, while the inter- 
 cepting valve is less dark in appearance. 
 
 From Figs. 169 and 170, it will be seen that 
 the right-hand end of the reducing valve is of 
 larger area than that acted upon by live steam at 
 
1 24 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 its seat on the left-hand end E. It is this dif- 
 ference that causes the partial closing of the 
 valve, thereby throttling the steam passing 
 through it to a reduced pressure. These areas 
 being about two to one, the reducing valve, in 
 order to equalize the work of the two cylinders 
 in starting, prevents more than about one-half 
 the pressure in the dry pipe from passing to the 
 low-pressure cylinder. 
 
 As soon as the high -pressure cylinder has ex- 
 hausted sufficient steam into the receiver to 
 overbalance the reduced live steam pressure 
 holding the intercepting valve closed, this valve 
 opens automatically, at the same time locking the 
 regulating valve against its seat as shown in Fig. 
 1 70. Exhaust steam from the high-pressure cyl- 
 inder then flows through the receiver to the low- 
 pressure steam chest, as indicated by the arrows 
 and the engine works compound. The receiver 
 pressure can become considerably reduced and 
 still, through the action of the combined valves, 
 keep the pressure regulating valve closed. 
 
 Accidents to Brooks Two-Cylinder Compounds. 
 What should be done in case of an accident 
 necessitating the removal of the main rod on the 
 low-pressure side? Disconnect that side, block 
 the crosshead and clamp the valve in center, as 
 with a simple engine. Open wide the control- 
 ling valves underneath the saddle and run in with 
 one side. The exhaust will take place through 
 these valves. To obtain a larger exhaust opening 
 than the controlling valves furnish and thus per- 
 mit of more speed and better steaming qualities, 
 
OPERATION OF COMPOUND LOCOMOTIVES. ' 125 
 
 attempt should be made to place the slide valve 
 on the disabled side so as to uncover the exhaust 
 port and thus give an exhaust through the stack. 
 
 What should be done for a similar accident 
 to the high-pressure side? Just the same as for 
 a simple engine. There being then no exhaust 
 into the receiver, the intercepting and reducing 
 valve would admit live steam to the low-press- 
 ure cylinder upon opening the engine throttle. 
 
 What mode of procedure should be followed in 
 case of a broken valve stem or rocker arm? Pro- 
 ceed as above, according to which side was broken. 
 
 What should be done if the intercepting 
 valve became broken so as to leave an open- 
 ing between both ends of the receiver? The 
 proper method would be to disconnect the small 
 steam pipe L (Figs. 167 and 168) and insert a 
 blind gasket. The engine could then be started 
 and worked only as a "strictly plain" compound 
 and should not be stopped with the high-pressure 
 side on center, as no live steam could be given 
 the low-pressure cylinder for starting. Without 
 disconnecting the steam pipe the engine could be 
 run in with part of a train by reducing the boiler 
 pressure or by using a slightly open throttle, in 
 which case live steam from the reducing valve 
 would pass through the receiver and work against 
 the high-pressure piston in starting, and hence 
 the engine should not then be stopped with the 
 low-pressure side on center. 
 
 What should be done for a broken reducing 
 yalve? The same as for a broken intercepting 
 valve, 
 
126 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 Should the controlling valves fail to open, 
 where would you look for the cause of the trouble ? 
 They operate very similarly to cylinder cocks and 
 their levers becoming disconnected or bent may 
 cause them to either fail to open, or remain con- 
 tinually open, as the case may be. The remedy 
 is obvious. 
 
 BROOKS FOUR-CYLINDER TANDEM COMPOUND. 
 
 The Brooks (Player System) of four-cylinder 
 compound is of the tandem type, that is, two 
 cylinders on each side, one ahead of the other, as 
 shown in Fig. 109. With this system the two 
 low-pressure cylinders and their saddles are placed 
 similarly to ordinary single-expansion cylinders, 
 with which they can always be made inter- 
 changeable. They are of course larger, have a 
 different style of steam chest and, bolted prefer- 
 ably to their forward ends, as shown in Figs. 109 
 and 171, are the two high-pressure cylinders 
 which have steam chests communicating with 
 the steam chests of the low-pressure cylinders 
 with an enlargement between, all together form- 
 ing a receiver. There are no devices in the 
 smoke-box except those usual to single-expan- 
 sion locomotives. 
 
 The steam is supplied to the high-pressure 
 valve chest through suitable pipes connecting 
 with the usual steam pipes in the smoke-box, and 
 the exhaust from the low-pressure cylinder is 
 through the usual cavity in the saddle. 
 
 As shown in Fig. 171, the low-pressure cylin- 
 ders are fitted with the usual balanced slide 
 
OPERATION OF COMPOUND LOCOMOTIVES 127 
 
 valves, while the valves for the high-pressure cyl- 
 inders are of the piston type and hollow, having 
 internal admission and external exhaust edges. 
 The low-pressure valve is controlled by the usual 
 eccentric and rocker arms, as ordinary with simple 
 engines'. It is rendered advisable to have an in- 
 ternal admission with the high-pressure valve in 
 order to lessen the cooling of the steam from the 
 boiler as well as for constructive reasons. 
 
 On account of the high-pressure valve having 
 internal admission and the low-pressure valve 
 having external admission (the latter being 
 usual with ordinary slide valves) it is necessary 
 that these valves should travel in opposite direc- 
 tions. This is accomplished by placing in the 
 receiver (as shown in Fig. 171) an intermediate 
 rocker arm A which is connected by rods to both 
 valves and has arms of the desired ratio to give 
 a relatively less travel to the high than to the 
 low-pressure valve. These valves are so propor- 
 tioned that when running in nearly full gear, the 
 high-pressure cut-off takes place later in the 
 stroke than the low-pressure cut-off, but when the 
 engine is hooked up the relative time of cut-offs 
 changes. 
 
 The pistons of both the high and the low- 
 pressure cylinder are fitted upon the same piston 
 rod, the intermediate head between the two 
 cylinders having suitable metallic packing, as 
 shown in the illustration. 
 
 On the low-pressure steam chest is fitted a re- 
 ducing and starting valve which is connected with 
 the high-pressure steam pipe, as shown with the 
 
128 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 <3 
 
 I 
 
 S 
 
OPERATION OF COMPOUND LOCOMOTIVES. 129 
 
 reducing valve in closed position by Fig. 172. 
 By the connection of a rod with the arm of the 
 lift shaft, this reducing valve is automatically 
 opened whenever the reverse lever is placed 
 either in full forward or full back gear. In the 
 intermediate positions of the reverse lever, this 
 reducing valve is locked to its seat by a suitable 
 spring, so that it is rendered inoperative and the 
 engine must necessarily work compound at all 
 
 &* /72 
 
 times and under all conditions of steam pressure 
 when the reverse lever is in any other position 
 than full gear. Fig. 172 shows the range of the 
 lift shaft arm for the starting valve to be either 
 open or closed. This combined starting and re- 
 ducing valve, when open, permits live steam to 
 enter the low-pressure cylinder at a pressure 
 equivalent to the maximum pressure obtained in 
 
130 ENGINEERS' AND FIREMEN'S MANUA L. 
 
 this cylinder when the engine is working com- 
 pound. As soon as the engine has made one 
 complete revolution, the receiver becomes charged 
 sufficiently by the exhaust from the high-pressure 
 cylinder to close the reducing valve against its 
 spring, thus automatically rendering the starting 
 
 valve inoperative and thereby necessitates the 
 compound working of the engine. The reducing 
 valve on a larger scale is shown in open or start- 
 ing position by Fig. 173. 
 
 The engine operates in the following manner: 
 Steam is admitted to the high-pressure steam 
 
OPERATION OF COMPOUND LOCOMOTIVES. 131 
 
 chest through suitable pipes, into the annular 
 steam admission cavity surrounding the high- 
 pressure piston valve, thence to the high-pressure 
 cylinder, and exhausts into the receiver the ex- 
 haust from the forward end of the cylinder pass- 
 ing through the inside of the hollow piston valve. 
 The low-pressure steam chest, being also of large 
 size, somewhat increases the receiver capacity, so 
 that practically uniform pressure is maintained 
 therein, steam from the receiver being admitted 
 to and exhausted from the low-pressure cylinder 
 by an ordinary slide valve which gives a dis- 
 tribution in that cylinder in the same manner as 
 for simple engines. 
 
 This style of compound has been in operation 
 for several years and, the builders state, shows an 
 excellent economy in fuel, water, and repairs. 
 
 Accidents to Brooks Four-Cylinder Tandem Com- 
 pound. What would you do if it became neces- 
 sary to disconnect one side of the engine? The 
 same as with a simple engine of similar design- 
 in other respects. 
 
 In case the front head of the high-pressure 
 cylinder became broken, how would you proceed 
 in order to run the engine in with a full train? 
 Remove the front steam chest head, place the 
 reverse lever so as to throw the high-pressure 
 valve clear ahead, disconnect the high-pressure 
 valve and its intermediate rocker-arm rod (Fig. 
 171) and block this valve securely in the center 
 so as to cover all ports; then block the starting 
 valve open on that side, thereby allowing live 
 steam at a reduced pressure to enter the low- 
 
132 ENGINEERS' AND FIREMEN'* MANUAL. 
 
 pressure cylinder. This will enable the engineer 
 to slowly handle a full train, but should not be 
 so run for any distance or the high-pressure cyl- 
 inder will be badly cut. In the lighter service of 
 passenger trains, the engine would be capable of 
 greater speed by disconnecting the broken side, 
 blocking the valves in the center of their seats, 
 and running with one side, as would be done with 
 a simple engine. 
 
 If the intermediate rocker arm or the valve rod 
 should break what should be done? Broken at 
 some certain points, the engine might be treated 
 as for broken high-pressure cylinder head; but 
 the preferable procedure, all things considered, 
 would be to disconnect on that side and be sure 
 to block both valves over ports, to do which it 
 may be necessary to remove front steam chest 
 head and block the high-pressure valve inside. 
 
 In disconnecting one side of these engines, 
 should it be imperative to securely block the 
 crosshead? It should, because of the difficulty 
 of securely holding the high-pressure valve in its 
 central position. 
 
 How could it be determined if the metallic 
 piston-rod packing between the two cylinders 
 were blowing badly? Place the engine with one 
 side on the upper quarter and the reverse lever 
 in the center, block open the starting valves, and 
 open the cylinder cocks and the throttle. If no 
 steam escapes from either the high or low-press- 
 ure cylinder cocks, it has been determined that 
 the valves are not leaking. Now close the 
 throttle and remove blocks from reducing valve, 
 
OPERATION OF COMPOUND LOCOMOTIVES, 1 33 
 
 put the reverse lever in about half forward gear 
 and allow all steam previously admitted to the 
 pipes to escape from the open cylinder cocks. 
 Again open the throttle and, as steam will then 
 be admitted behind the high-pressure piston only, 
 a blow through the forward low-pressure cylinder 
 cock would indicate that this packing was blowing. 
 The same operation should be repeated for test- 
 ing the other side. 
 
 Should the engine fail to develop its proper 
 starting power in full gear, what might be wrong? 
 Open the cylinder cocks, with the throttle open 
 and the engine standing, and if steam at no con- 
 siderable pressure escapes from the low-pressure 
 cylinder, examine the attachments connecting the 
 reverse lever with the starting valves; they oper- 
 ate similarly to the ordinary cylinder cock ar- 
 rangement and may likewise become defective 
 and thus fail to open the reducing valve. 
 
COOKE COMPOUND. 
 
 The compound arrangement for two-cylinder 
 locomotives built by the Cooke Locomotive 
 Works is such that, by means of a small steam 
 
 FIG. 174. COOKE COMPOUND. 
 
 operating valve in the cab, the engine can be 
 run either simple or compound as the engineer 
 may desire, and is, therefore, a convertible com- 
 pound. This operating valve admits steam to 
 suitable pistons which open and close the inter- 
 
 (134) 
 
OPERATION OF COMPOUND LOCOMOTIVE*. 1 35 
 
 cepting valve and operate the reducing valve by 
 a suitable lever connection. The intercepting 
 valve is placed on the right-hand side of the en- 
 gine within the saddle of the low-pressure cyl- 
 inder and in the passages JS1?, leading from the 
 receiver to the low-pressure cylinder, as shown 
 in Fig. 174; it also has two connecting ports AA, 
 leading into the main exhaust to the stack. By 
 the movement of this valve, steam from the high- 
 pressure cylinder, coming through the receiver, 
 can be thrown out to the atmosphere instead 
 of being allowed to pass to the low-pressure cyl- 
 
 Fiy.175. 
 
 inder for compound expansion. This movement 
 makes an independent engine of the high-press- 
 ure side and at the same time opens a reducing 
 valve D, Fig. 174, which supplies, at a reduced 
 pressure, live steam from the boiler to the low- 
 pressure steam chest. The high-pressure cylinder 
 always exhausts into the receiver, and the ex- 
 haust from the low-pressure cylinder is direct to 
 the stack with either simple or compound 
 working. 
 
 The reader will notice a novelty in the shape 
 
136 
 
 ENGINEERS' AND FTREWEN'* MANUAL. 
 
 of an additional low-pressure cut-off lever G, 
 located in the cab, as shown in Fig. 174. This 
 lever is sometimes applied to Cooke engines of 
 this class and is used to increase or decrease the 
 travel of the slide valve on the low-pressure side 
 independently of the valve on the high-pressure 
 side, in order to equalize the power developed on 
 opposite sides of the engine under variable con- 
 ditions of steam pressure and different positions 
 of the reverse lever. 
 
 /77 
 
 The intercepting valve is composed of two 
 pistons in duplicate, as shown in Figs. 174, 177 
 and 178, each part being moved by a piston F in a 
 separate chamber. Figs. 175 and 176 show one- 
 half of the valve removed from its chamber. It 
 will readily be seen from Fig. 174, that live 
 steam from the engineer's valve V in the cab can 
 be supplied through two small pipes S and C to 
 either the outer or the inner sides, respectively, 
 of these two pistons FF. Ports ER are passages 
 
OPERATION OF COMPOUND LOCOMOTIVES. 1 37 
 
 from the receiver and ports EE lead to the low- 
 pressure steam chest. 
 
 To start the engine with single expansion or 
 to run it thus at any time, the engineer pulls the 
 handle of his engineer's valve V in the cab to the 
 back notch. This admits live steam through the 
 small pipe S (Fig. 174) to outside ends of the two 
 pistons FI\ thereby moving them and their at- 
 tached intercepting valve pistons until the two 
 latter come together, the position in which they 
 
 are shown on a larger scale in Fig. 177. In this 
 position the intercepting valve has closed the 
 ports EE to the low-pressure cylinder, and the 
 high-pressure exhaust into the receiver can pass 
 out from ports RR, through the hollow intercept- 
 ing valves and escape to the atmosphere by 
 exhaust ports A A leading to the main exhaust, as 
 indicated by arrows. The extended and slotted stem 
 of the left-hand intercepting valve piston JF( shown 
 in Figs. 174 and 175) in moving to the right has 
 
1 38 ENGINEERS' AND FIREMEN^ MANUAL. 
 
 pulled with it the crank lever J^(Fig. 174) and 
 opened the reducing valve 1) which, by a con- 
 necting pipe tapped into the main steam passage 
 of the high-pressure side, admits live steam to 
 the low-pressure steam chest through pipe J. 
 
 When the engineer desires to work compound, 
 he pushes the handle of the engineer's valve Fin 
 the cab to the forward notch, thereby admitting 
 steam through pipe C (Fig. 174) to the inner 
 sides of the two intercepting valve pistons FF 
 and forcing them and their valves outward, as 
 shown in Fig. 178. In this position the passage 
 is opened from -the receiver through the inter- 
 cepting valve ports EE and EE to the low- 
 pressure steam chest (See Fig. 174). The out- 
 ward movement of the pistons FF has shut off the 
 admission of live steam to the low-pressure cyl- 
 inder by closing the reducing valve D, and the 
 steam must now pass from the high-pressure cylin- 
 der through the receiver and the low-pressure cyl- 
 inder to the exhaust or, in other words, the engine 
 works compound. 
 
 Each stem between the operating pistons FF 
 and the intercepting valve pistons has an enlarge- 
 ment B (Figs. 175, 177 and 178) which fits 
 loosely into a chamber of the intercepting valve 
 bushing and thus forms an air dash-pot, thereby 
 preventing the slamming of the valves when 
 their positions are changed. 
 
 The stem of the piston F which extends back 
 to operate the reducing valve D is slotted out, as 
 shown in Fig. 175, so as not to engage the valve 
 crank K (Fig. 174) until after the intercepting 
 
OPERATION OF COMPOUND LOCOMOTI VE8. 139 
 
 valve has closed the ports EE. Thus the live 
 steam used in the low-pressure cylinder in starting 
 cannot reach the high-pressure side through the 
 receiver and produce a back pressure on the high- 
 pressure piston. 
 
 The builders state that in case of accident to 
 either side of the engine, the opposite side may 
 be run for any length of time as a simple engine 
 by disconnecting and blocking the injured side in 
 the same manner as for single-expansion loco- 
 motives. 
 
DICKSON COMPOUND. 
 
 The Dickson Locomotive Works' compound is 
 built under the Dean patents which cover special 
 valves both for automatic and for convertible 
 compounds, but, inasmuch as the practical infor- 
 mation is based on the mechanism for the former 
 class only, the detailed description will be con- 
 fined to the automatic compound. 
 
 The starting and intercepting valves are placed 
 on top of the high-pressure steam chest on the 
 right side of the engine. Upon opening the throt- 
 tle for starting, live steam is admitted to both 
 cylinders, but, after a stroke or two, the inter- 
 cepting valve automatically opens and the engine 
 works compound thereafter. 
 
 The high-pressure exhaust port Q (Fig. 179) is in 
 the balance shield of a Richardson balanced valve 
 P, having its top removed, and thus the exhaust 
 steam from the high-pressure cylinder passes up 
 through it and the intercepting valve G to the 
 receiver and low-pressure cylinder, when the in- 
 tercepting valve G is open. Beneath the seat R, 
 intercepting valve G, is a port E l leading to the 
 chamber E. 
 
 The receiver, as usual with cross-compounds, is 
 located in the smoke-box, but its shape is out of 
 the ordinary. It is made very large and, between 
 its connections with the high and the low- 
 pressure saddles, branches into two forks, each of 
 which is oval and has metal ribs lengthwise with 
 the pipes, Fig. 180 shows a section through this 
 
 (140) 
 
OPERATION OF COMPOUND LOCOMOTIVE*. 141 
 
 double portion of the receiver. The object of the 
 designer has been to obtain a very large heating 
 surface, so as to re-evaporate some of the water 
 
 C/tesf 
 
 condensed in the high-pressure cylinder as it 
 passes with the exhaust steam through the re- 
 ceiver to the low-pressure side. From the re- 
 
142 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 ported economy of these engines, it would seem 
 that the object has been largely attained. 
 
 Referring to Figs. 179 and 181, it will be seen 
 that the intercepting valve G is fastened to the 
 annular stem H having an enlarged top above 
 the space B which is constantly filled with air 
 pressure or live steam from the pipe C when the 
 engine throttle is open, and hence sleeve H will 
 be found at the top of its travel, as illustrated, 
 after the engine has started. 
 
 The operation is as follows: Open the throttle 
 for starting and live steam enters the high- 
 pressure steam chest from the induction ports 7 
 
 Fig.180. 
 
 (Fig. 179) as usual and besides has a connec- 
 tion to F through the top of the steam chest, as 
 shown. There being no pressure in the receiver 
 (to which chamber E is connected through 
 the open intercepting valve G\ the weight of 
 N will have caused the converting valve L 
 to drop down, and thus the live steam passes 
 through valve L into the tube AJ. Port K ad- 
 mits steam to the enlarged top of the annular 
 stem H, forcing the intercepting valve G down on 
 its seat R and bringing the ports D in the stem H 
 opposite the ports J of the central steam tube A, 
 thus admitting live steam through them to the 
 
OPERATION OF COMPOUND LOGOMOTI VEti. 143 
 
 receiver and low-pressure steam chest. With the 
 intercepting valve G closed (down), the first 
 high-pressure exhaust, acting in chamber E 
 through the port E 1 , causes piston N to lift and 
 close the converting valve L (as shown in Figs. 
 179 and 181), thereby shutting off the supply of 
 steam from F to the central tube AJ. What 
 
 steam remains in this tube escapes through the 
 relief port M and allows the intercepting valve G 
 to move up (open) by live steam pressure from 
 the pipe C acting in the annular cavity B, as 
 hereinbefore described, assisted by the high- 
 pressure exhaust below G. The engine then 
 works compound, as live steam is shut off from 
 
144 ENGINEERS' AXD FIREMEN'S MANUAL. 
 
 the low-pressure cylinder and the exhaust from 
 the high-pressure cylinder takes its place. 
 
 The engine above described is an automatic 
 compound, that is ; starts with live steam in both 
 cylinders but after the first stroke changes auto- 
 matically to compound. 
 
 The inventor of this system, in a design not 
 shown, introduces a reducing valve in the central 
 tube A and adds a separate exhaust valve operated 
 by live steam from a three-way cock in the cab, 
 thus making a compound of the convertible class, 
 but at the same time he does not advise convert- 
 ible construction in compounds. 
 
 Accidents to Dickson Compounds. What should 
 be done in order to run the engine in with the 
 low-pressure side only ? Nothing different from 
 a simple engine, but the boiler pressure carried 
 should be reduced about one-half or else the 
 engine throttle opened very slightly. 
 
 How could the engine run with the high-press- 
 ure side only? There being no means of exhaust 
 except into the receiver, the low-pressure valve 
 would have to be placed so as to uncover the 
 exhaust port or, if that were found to be impos- 
 sible, the valve entirely removed. 
 
RHODE ISLAND COMPOUND. 
 
 The type of compound locomotive built by the 
 Rhode Island Locomotive Works is sometimes 
 known as the "Batchellor" system, that being 
 the name of the inventor of the device. 
 
 In the saddle of the low-pressure cylinder on 
 the left side of the locomotive is located an inter- 
 cepting and a reducing valve and in the smoke- 
 box a separate high-pressure exhaust valve. 
 When the throttle is opened, the engine starts 
 with live steam in both cylinders. With the 
 separate exhaust valve closed the engine auto- 
 matically changes to compound in the course of 
 a complete revolution; with it open, the engine 
 continues to work as a simple engine as long as 
 desired. This separate exhaust valve is operated 
 at the will of the engineer by means of a three- 
 way cock in the cab; and thus the engine belongs 
 to the class of convertible compounds. 
 
 Fig. 182 shows a vertical section lengthwise 
 through the intercepting valve, with the latter in 
 the position when the engine is either starting 
 or being run as a single-expansion locomotive. 
 Fig. 183 shows the same section with the inter- 
 cepting valve in compound position. R is the 
 receiver port; $ is a connection from the main 
 steam pipe; L is a port leading to the low-press- 
 ure steam chest, and B is a reducing valve. The 
 intercepting valve is composed of the four pistons, 
 1, 2, 3 and 4, of which the last works in an oil 
 dash-pot C. 
 
 (145) 
 
146 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 If the engine had stopped after running com- 
 pound with the valve, as in Fig. 183, and the en- 
 gine throttle were then opened, live steam from 
 the pipe S would force the intercepting valve 
 into simple position as shown in Fig. 182, because 
 piston 2 is larger than piston 7. In this latter 
 position small port D is open and steam from S 
 passes through it and the reducing valve B to 
 the low-pressure side. Piston 3 has now closed the 
 communication with the receiver R in which one 
 
 or two exhausts from the high-pressure cylinder 
 soon produces sufficient pressure to react on this 
 piston 3, bearing the intercepting valve to the 
 left against the differential pressures on pistons 
 1 and 2 acting in the opposite direction, and the 
 valve is shifted to compound position, as in Fig. 
 183, in which position no more live steam can 
 pass through port D to the low-pressure side, and 
 
OPERATION OF COMPOUND LOCOMOTIVES. 147 
 
 the receiver E is connected through port L with 
 the low-pressure steam chest, for which it forms 
 the supply thereafter, as indicated by the arrows. 
 
 The port leading from the live steam supply 8 
 into the intercepting valve, is larger than it 
 appears from the illustrations, as it extends partly 
 around the circumference of the valve. 
 
 The separate exhaust valve shown in Figs. 184 
 and 185 is placed on the receiver in the smoke- 
 
 box and, when opened by pressure through pipe 
 P leading from a three-way cock located in the 
 cab and under the control of the engineer, con- 
 nects the receiver with the main exhaust pipe. 
 The opening of this valve will thus permit the 
 high-pressure exhaust to escape and there will 
 be no accumulation of pressure in the receiver. 
 Hence, from the previous explanation, it will be 
 seen that the intercepting valve remains in sim- 
 
148 
 
 ENGINEERS' AND FIREMEN'S MANUAL. 
 
 pie position (Fig. 182) until such time as the 
 engineer closes the separate exhaust valve, when 
 a stroke of the engine automatically changes the 
 mechanism to compound position, as before de- 
 scribed when starting. 
 
 The operation of the separate exhaust valve, 
 shown in Figs. 184 and 185, is very simple. Press- 
 ure admitted from the cab through pipe P, 
 moves the valve Ffrom its closed position (Fig. 
 185) to the right and vents the receiver pressure 
 direct to the exhaust pipe, as indicated by the 
 
 -.185. 
 
 Open JfnyineWar-TCiny/Sif/nple.. Closed-iZnyine Compnn. n 
 
 arrows, Fig. 184. Withdrawing the pressure 
 from the pipe P, allows the receiver pressure to 
 automatically move and hold closed the valve V, 
 as in Fig. 185. 
 
 Accidents to Rhode Island Compound. If it be- 
 came necessary to disconnect either side, how 
 should the engine be run ? Disconnect properly, 
 observing the same precautions advised for sim- 
 ple engines, then open the separate exhaust 
 
OPERATION OF COMPOUND LOCOMOTIVES. 149 
 
 valve so that no pressure can accumulate in the 
 
 receiver/" 
 
 What would you do with a broken intercept- 
 ing or reducing valve? Open the separate ex- 
 haust valve and run with very light throttle, or, 
 preferably, carry a reduced boiler pressure. 
 
 Would the working of the engine be affected 
 if the separate exhaust valve V were broken? 
 Probably not; but, if it left an opening between 
 the receiver and the exhaust, the engine would 
 run as a simple locomotive only. 
 
 *As remarked elsewhere in relation to designs having a sep- 
 arate exhaust valve, if it were the high-pressure side that was 
 disconnected, it would not be necessary to open the separate ex- 
 haust valve unless there was some leakage of steam into the 
 receiver. 
 
THE SCIENCE OF RAILWAYS, 
 
 IN TWELVE VOLUMES. 
 BY MAESHALL M. KIEKMAN. 
 
 REVISED AND ENLARGED EDITION. 
 
 SCIENCE OF BAIL WAYS" DESCRIBES THE METHODS 
 
 AND PRINCIPLES CONNECTED WITH THE EQUIPMENT, 
 
 SHOPS, ORGANIZATION, LOCATION, CAPITALIZATION, 
 
 CONSTRUCTION, MAINTENANCE, OPERATION 
 
 AND ADMINISTRATION OF EAILROADS. 
 
 This great work is everywhere commended for its 
 thoroughness, vast research and impartial represen- 
 tation. While it treats of specific things, it does not 
 reflect the methods of any particular property or country. 
 A treasury of research and practical experience, it por- 
 trays truly and vividly the principles and practices of 
 the great art of transportation in their highest and best 
 forms. It is popular in every place where railroading 
 has reached its highest development, and the endorse- 
 ment it has received from railway men of the highest 
 attainments is conclusive evidence of its value and trust- 
 worthiness. 
 
 PUBLISHED BY 
 
 THE WORLD KAIL WAY PUBLISHING COMPANY, 
 CHICAGO, ILL. 
 
 (540) 
 
ORIGIN AND EVOLUTION OF 
 TRANSPORTATION." 
 
 BY 
 MARSHALL M. KIRKMAN. 
 
 [NOTE. The first chapter in this volume on the " Evolution of Man," has 
 been incorporated since the commendatory notices of the distinguished men 
 and women named below, were written. Originally the volume embraced only 
 the chapters on the Ancients, and the pictures that accompanied the same.] 
 
 "For originality of design and thorough treatment of its subject, it is 
 unique among books. Disraeli would have enshrined it among his 'Curi- 
 osities of Literature' as a stroke of genius." Right Reverend WILLIAM E. 
 MCLAREN, D. D., D. C. L., Bishop of Chicago. 
 
 "It is a work that has great value as a conspectus of the nomadic and 
 other tribes of men, including their contrivances for locomotion. It fascin- 
 ated me, and I spent the evening poring over its wonderful contents, which 
 are most instructive as well as curious. Every great school, and every college 
 in the world, should possess a book so peculiar and the result of so much 
 research." Right Reverend A. CLEVELAND Cox, D. D., LL.D., late Bishop of 
 Western New York. 
 
 "It was a most happy thought that conceived such a work, and in its exe- 
 cution it becomes a most instructive and suggestive contribution to our best 
 literature." Right Reverend HENRT C. POTTER, D. D., LL D., D. C. L., Bishop 
 of New York. 
 
 "It treats well and artistically a comparatively new field of literature." 
 His JSminence JAMES CARDINAL GIBBONS, D. D., Archbishop of Baltimore. 
 
 "The Classical Portfolio is remarkable for the exact historical and geo- 
 graphical information which it imparts, and for the high art which is visible 
 in its engravings. I can not but marvel at the patience, the vast erudition, the 
 literary skill, the esthetic taste of which its pages from first to last give such 
 indisputable evidences. The book instructs and delights. No sooner is it 
 seen than it is appreciated." Most Reverend JOHN IRELAND, D. D., Archbishop 
 of St. Paul. 
 
 The august rulers of the world find the Portfolio quite as fascinating as 
 do their more simple brethren. Love of art, it is thus apparent, knows no 
 degree of rank. His Majesty, King Humbert of Italy, expresses, through his 
 Minister of State, the pleasure the Portfolio has offorded him, and his high 
 appreciation of its great merit. His Majesty, Leopold, King of Belgium, 
 through his Chief of Cabinet, characterizes the Portfolio as a most remark- 
 able and interesting publication and one that elicits his great admiration. His 
 Majesty, the King of Greece, says of the Portfolio that it is at once an artistic, 
 interesting and magnificent production. Many others have been so kind as to 
 express their thanks to the author for the pleasure this rare and beautiful work 
 of art has afforded them. Among the more exalted of these may be men- 
 tioned Her Most Gracious Majesty, The Queen of England, and His Imperial 
 Majesty, The Czar of Russia. 
 
 (541) 
 
"A most interesting and valuable work." NELSON A. MILKS. Major Gen- 
 eral, Commanding United States Army. 
 
 "The work is a splendid one, both from artistic and literary points of 
 view." WESLEY MERBITT, Major General, U. S. A. 
 
 " Mr. Kirkman's researches have taken him into every quarter of the globe, 
 and among every race of man. The illustrations depict every known method 
 of carriage, . . . besides pictures of ancients, medieval and mythological 
 means of carriage. . . . The value of this vast collection is greatly 
 enhanced by the explanations and the dates that are affixed to most of the 
 illustrations, and by the brief historical essays that are prefixed to the several 
 subdivisions." New York Daily Tribune. 
 
 "A superb volume, original in conception and unique in literature and 
 art.' 1 JOSEPH MEDILL, Proprietor Chicago Tribune. 
 
 " One of the most exhaustive and valuable books in the world in any given 
 line. It is impossible to say too much in praise of this noble work. . . . 
 Mr. Kirkman is a railroad man of great ability, but he is more, and that is a 
 distinct benefactor to the learning of the world." The Boston Traveler. 
 
 "A more interesting series of illustrations it would be difficult to imagine, 
 or one that could give more clear and positive instruction in the history of 
 humanity. Mr. Kirkman is a distinguished railroad man, and thus he came 
 naturally to the studies which are embodied in this beautiful and comprehen- 
 sive volume." New York Sun. 
 
 "This volume is especially interesting by reason of its presentation of its 
 subject through a progressive series of excellent pictures following the line of 
 historical development." Dr. TIMOTHY DWIGHT, President Yale University. 
 
 "A book prepared with great care and cost, and possessed of great merit 
 in point of beauty; it is exceedingly interesting and instructive. I am glad to 
 add my testimony to that of others with respect to its excellence." Dr. 
 FRANCIS L. PATTON, President Princeton College. 
 
 "Truly unique, instructive, beautiful and fascinating. I consider it a 
 valuable contribution to literature." HENRY WADE ROGERS, LL.D., President 
 North-Western University. 
 
 "A magnificent volume, . . . most interesting and admirable. It is an 
 illustrated study of the means of travel and transportation in every country 
 in the world that has any; and from the most primitive times down to the 
 present. The profusion of illustrations and their beauty render the work a 
 mine of instructive enjoyment, and I find it interests all who see it." JENNY 
 CUNNINGHAM CROLY. 
 
 "Artistic and valuable, and, despite all traditionary statements to the con- 
 trary, something new under the sun." ELIZABETH BOYNTON HARBERT. 
 
 "Exceedingly beautiful, and worthy of all the best words that can be said 
 in its behalf." MARY LOWE DICKINSON. 
 
 (542) 
 
PARTICULARS IN REGARD TO THE SALE, DELIVERY, 
 PAYMENT, ETC., OF THE 
 
 SCIENCE OF RAILWAYS." 
 
 The work may be paid for in monthly installments. In such 
 cases the books will be delivered as fast as paid for. 
 
 In all cases, however, the publishers reserve the right to 
 deliver the books in advance of payment if they so elect. 
 
 Payments may be made according to the following plans, as 
 may be agreed upon, viz: 
 
 1. In one payment. 
 
 2. By remitting draft or postoffice order to the pub- 
 
 lishers (or such person or persons as they may 
 direct) , for the amount of the installments. 
 
 3. In the case of those in the service of corporations, 
 
 orders on the proper officer thereof will be ac- 
 cepted when the publishers are able to arrange 
 with the company to collect the same. 
 
 Only those who are duly authorized in writing can collect 
 money on account of the work. 
 
 The Publishing Company has had this edition electrotyped. 
 Those who wish all the books delivered at one time may, there- 
 fore, expect to receive them without sensible delay. Those who 
 wish them in single volumes from month to month may also 
 confidently anticipate delivery at the time specified. 
 
 The work is sold only by subscription. 
 
 The World Hallway Publishing Company, 
 
 79 Dearborn St., Chicago, III. 
 
 (548) 
 

 LIBRARY USE 
 
 RETURN TO DESK FROM WHICH BORROWED 
 
 MAIN LIBRARY 
 CIRCULATION DEPARTMENT 
 
 THIS BOOK IS DUE BEFORE CLOSING TIME 
 ON LAST DATE STAMPED BELOW 
 
 L,D62A-30m-7,'73 
 (R2278lO)9412-A-32 
 
 General Library 
 
 University of California 
 
 Berkeley