Catechism of the locomotive

Front matter

- o o x

A *

1 ^

Preface

Books, like individuals, have their histories, and it seems but proper that in introducing them somewhat of their ancestry should be detailed. The present book originated in this wise : the publishers of the Kailroad Gazette procured a copy of the "Katechismus der Einrichtung und des Betriebes der Locomotive," by Georg Kosak. As no English translation of this excellent little book was known to be in existence, the editors of the above paper determined to translate it and adapt it to the American practice in the construction and management of locomotive steam engines, and republish it in their journal. The translation was therefore made and submitted to the writer for revision and adaptation, according to the original intention. Before the latter was entertained, however, he had commenced writing an elementary treatise on the locomotive. In revising the first part of the translation of Mr. Kosak's book, it was found that the latter occupied only to a very limited extent the ground which the writer had " staked out " in his own incomplete plan. He therefore concluded to abaniv Preface.

don the original intention of " adapting" Mr. Kosak's work, and determined to rewrite it and make substantially a new book of it. For the " idea," however, and to some extent its plan, and for much valuable material, the author must acknowledge his indebtedness to Mr. Kosak. In some few cases the language of the translator has been employed, in part or in whole, without quotation marks, but with an acknowledgment in a foot-note. A similar plan has also been pursued in using some other books. This was done to avoid cutting up paragraphs and sentences into fragmentary parts with numerous quotation marks.

The following books have been consulted and used in writing the Catechism of the Locomotive : Heat considered as a Mode of Motion, by Prof. Tyndall; The Conservation of Energy, by Balfour Stewart; Railway Machinery, by D. K. Clark ; Treatise on the Locomotive Engine, by Zerah Colburn; Treatise on the Steam Engine, by W. J. M. Rankine ; Indicator Experiments on Locomotives, by Professor Bauschinger ; Richards' Steam Indicator, by Charles T. Porter ; Die Schule des Locomotivfuhrers, by J. Brosius and R. Koch ; Mechanics, by A. Morin ; The New Chemistry, by J. P. Cooke, Jr. ; Combustion of Coal and the Prevention of Smoke, by C. Wye Williams ; A Treatise on Steam Boilers, by Robert Wilson ; Reports of the American Railway Master Mechanics' Association ; Link Valve Motion, by William S. Auchincloss, and

Preface. v

Emergencies and How to Treat Them, by Dr. Joseph W. Howe.

For the title of the book an apology is perhaps needed, as the word Catechism is associated in nearly all persons' minds we will trust with early religious and theological instruction, and therefore a Catechism of the Locomotive is very apt to sound more ludicrous than scientific. The title of Mr. Kosak's book was adopted before it was determined to rewrite it, and it was afterwards not deemed best to change it. To those who are disposed to smile at it, the precedent of Mr. Bourne's excellent Catechism of the Steam Engine is quoted, and if they will refer to Webster's Dictionary for the definition of the word " catechism," they will find that it means "an elementary book containing a summary of principles in any science or art, but appropriately in religion, reduced to the form of questions and answers, and sometimes with notes, explanations and reference to authorities," which is exactly what the present book is intended to be.

To persons accustomed to, books and study, the catechetical form is very apt to seem cumbrous and awkward, but it has some very decided advantages in writing for those who have not acquired studious habits of thought. To such the question asked presents first a distinct image of the subject to be considered, so that the explanation or instruction which follows is much vi Preface,

more apt to be understood than it would be if no such question had been asked.

The author is indebted to Mr. D. B. Grant for the use of drawings from which most of the engravings of details of locomotives with which this book is illustrated have been made, and to other locomotive builders, whose engines are illustrated in the full-page plates, for the drawings thereof. He has also received very valuable aid from Mr. Richard H. Buel, Mechanical Engineer; Mr. William Buchanan, Master Mechanic of the Hudson River Railroad ; Mr. Frank D. Child, Superintendent of the Hinkley Locomotive Works ; and Mr. E. T. Jeffrey, Assistant Superintendent of Machinery of the Illinois Central Railroad.

The object in writing the book was to furnish a clear and easily understood description of the principles, construction and operation of the locomotive engine of the present day, a subject which is not concisely or adequately treated in any one similar book. If the author has succeeded in making what he has written plain to plain people, his aim will be fully accomplished.

No. 73 Broadway, New York.

Contents

PAGE

Preface m

Introduction i x

Part I. The Steam Engine 1

II. The forces of Air and Steam 8

III. On Work, Energy and the Mechanical Equivalent

of Heat 22

IV. The Slide- Valve 30

V. The Expansion of Steam 47

VI. General Description of a Locomotive Engine . 62

VII. The Locomotive Boiler 71

VIII. The Boiler Attachments 115

IX. The Throttle- Valve and Steam-Pipes .... 155 X. The Cylinders, Pistons, Guide-Rods and Connecting-Rods 164

XL The Valve-Gear 181

XII. The Running-Gear 268

XIII. Adhesion and Traction 319

XIV. Internal Disturbing Forces in the Locomotive 328 XV. Miscellaneous 335

XVI. Screw Threads, Bolts and Nuts 341

XVII. Tenders 349

XVIII. Friction and Lubrication 358

XIX. Combustion 365

XX. The Resistance of Trains 406 vm

Contents.

PAGE.

XXI. Proportions of Locomotives 412

XXII. Different Kinds of Locomotives 427

XXIII. Continuous Train Brakes 442

XXIV. Performance and Cost of Operating Locomotives 448 XXV. Water-Tanks and Turn-Tables 451

XXVI. Inspection of Locomotives 461

XXVII. Running Locomotives 478

XXVm. Accidents to Locomotives 509

XXIX. Accidents and Injuries to Persons 533

XXX. Responsibility and Qualification of Locomotive

Runners 544

List of Books for Mechanics, Locomotive Runners, Firemen, etc., 550

Plates 551

Appendix

I. Table of the Properties of Steam .585

II. Table of Hyperbolic Logarithims 590

III. Table of the Properties of Different Kinds of Fuel . 594

IV. Table of the Resistance of Trains 596

Introduction

The Catechism of the Locomotive is intended for a large class of readers, among whom are all kinds of railroad officers and employes, consisting of locomotive runners, firemen, and the many different kinds of mechanics employed in railroad shops and in the construction of locomotive and other kinds of railroad machinery and material. Besides these there are many amateur engineers, students, and persons interested directly or indirectly in railroads, and a not inconsiderable class who are always seeking information on all subjects whatsoever. It is evident, therefore, that the only way to adapt the book to all the classes for whom it is intended, was to make it so plain that the "wayfaring man" will have no difficulty in comprehending it. It has therefore been written in as clear language as the writer could command, and the subjects presented are treated as simply and as plainly as his ability enabled him to do, and with the least possible employment of either scientific or practical technicalities. The only deviation from this plan will x Introduction.

be found in the use of algebraic symbols to designate arithmetical calculations. This was done to save space, and because it was thought that they could be explained so that even those without any knowledge whatsoever of algebra could easily comprehend them. To such as have no such knowledge the following explanation is given :

Suppose it is necessary to add two numbers, say 1,872 and 468. The calculation, if made arithmetically, would be thus :

1,872 468

2,340 This it will be seen occupies the space of several lines of print. If we want to express this calculation algebraically, it can be done by simply writing the two numbers and placing the sign +, called plus, between the two, which indicates that they are to be added together, thus :

1,872+468 To indicate what the sum will be, or what the two added together will amount to, the sign = , called equal to, or the sign of equality, is placed after the two numbers and between them and the sum, thus :

1,872+468=2,340, which can be read as follows :

1,872 added to 468 is equal to 2,340. Now the only use of the algebraic signs + and = is

Introduction. xi

that they save time in writing and room in printing, and when persons become accustomed to their use they make plain a number of operations at a single glance, as will be shown hereafter.

In the same way that the sign + means added to, the sign — means less or subtracted from, thus : 1 ? 872 — 468=1,404,

which is the same as though it was printed as follows : 1,872 less 468 is equal to 1,404.

The sign X means multiplied by, or is the sign of multiplication. Thus :

1,872 multiplied by 468 is equal to 876,096. The sign -V- means divided by, thus : 1,872^-468=4.

which means :

1,872 divided by 468 is equal to 4.

The same thing is expressed by putting a line under the dividend and writing the divisor under the line, thus :

1,872

468 These signs are combined in various ways. Thus, supposing we wanted to add 1,872 to 468 and then divide the sum by 117, it would be necessary, in order xii Introduction.

to represent the arithmetical calculation, to do it as

follows :

1872 468

117)2340(20 234

Algebraically it would be stated thus

1872+468

If you wanted to add 124 to the quotient 20 above.

the calculation would be as follows :

1872 468

117)2340( 20 234 124

This operation could be expressed by writing it as

follows :

1872+468

+ 124=144.

If we wanted to multiply the quotient 20 by 124

we would simply put the sign X instead of + before

1872 + 468

Introduction.

xni

The sign of subtraction or division can be used in the same way.

With these explanations it is believed that any one, with nothing more than an ordinary knowledge of the four elementary rules of arithmetic, can understand all the mathematics contained in the following pages. A little explanation may also be needed of the method of representing machinery and other structures by mechanical drawings.

If we want to represent the outside of any object, say an apple, we make a drawing of it as shown at A.

Now if we want to show the inside of the apple, say the seeds and core, we can cut it in half and represent

B xiv Introduction.

it as shown at G, which is then called a section or sec-* iional view of the apple. If we represent it as it will appear if we are above it and looking down on it as shown at B, it is called a top view or plan.

It is evident, too, that it might be desirable to show the arrangement of the seeds in the apple as they would appear if it was cut through in the other direction, say on the line a b, fig. A, and as is shown at D. There are therefore two kinds of sections ; one G, in which the object is supposed to be cut through vertically, and therefore called a vertical section, the other when the object is supposed to be cut through horizontally, and therefore called a horizontal section, as shown at D.

It is also evident that in looking at a locomotive or any other object, the appearance of the engine depends upon our position in relation to it. Thus, if we stand on the side of it, we see that part of the engine, and a drawing which represents the side, is therefore called a side view or side elevation. A drawing which represents a locomotive or other object as it would appear to us if we stood in front of it, is called a front view or front elevation , and a representation of the back part of any object as it would appear to us if we stood behind it is called a back view or back elevation. Plate I is a side view, Plate II a section, Plate III a top view or plan ;*

* The boiler of the locomotive is supposed to be removed in Plate III,

Introduction, xv

the vignette in the title page is a front view and fig. 71 a back view of a locomotive. If the drawing is made as the object would appear if it was turned upside down, and we were looking at it from above, then it is called an inverted plan.

It is obvious, too, that it is possible to make a great many different sectional views of nearly any object, especially of a machine. Thus, we could suppose a locomotive cut through vertically and lengthwise, as is shown in Plate II. Such a representation is called a longitudinal section. A locomotive could also be cut through crosswise, as shown in fig. 40, which is called a transverse section. It is of course possible to represent a transverse section of a machine like a locomotive at a great many different points ; for example, it could be shown as though it was cut through the smoke-stack as in fig. 40, or through the boiler farther back, as the latter is shown in fig. 42. Usually when a section is shown through a cylindrical object like a smoke-stack or boiler, it is shown through its centre. If, however, this is not apparent from the drawing or engraving, it should be stated at what point it is supposed to be taken, thus the section D of the apple is on the line a b of fig. A, and the section O is on the line c d.

In drawing sections, the parts which are supposed to be cut in two are usually shaded with parallel diagonal lines drawn at equal distances apart, as shown in xvi Introduction.

the sections of the apple at A and B. Sections are also sometimes represented with solid black surfaces, as in Plates II and III, and in the engraving of a pump in fig. 66.

Objects which are behind others which are in front of them are often shown with dotted lines, so as to indicate their position. The seeds of the apple are thus indicated at A.

It is also customary, in drawings of machinery, to take great liberties with the objects represented and to show them with parts removed or broken away, if their construction can thus be made plainer. It should be remembered that the purpose of drawings of this kind is not to give a pictorial representation of the object as it appears to the eye, but to make its construction and mode of operation apparent to the mind. In such drawings therefore all perspective is disregarded. It would lead us too far were we to explain the reasons for this, and therefore readers must accept the assertion without the proof.

CATECHISM OF THE LOCOMOTIVE.

PART I.

THE STEAM ENGINE.

Question 1. What is the motive power employed in ordinary steam engines ?

Answer. The expansive force of steam.

Question 2. How is this expansive force of steam applied?

Answer. It is applied by admitting it into a cylinder

Fig.l.

Scale | in.=l foot.

A. Cylinder.

B. Piston.

G. Back Cylinder- Head.

R. Piston- Rod.

D. Front Cylinder-Head.

(-4, fig. 1) in which a piston, B, is fitted so as to move air-tight from one end of the cylinder to the other. The steam, if admitted at c, will force the piston B to the opposite end* of the cylinder. When it has reached that end, if the steam is allowed to escape and a fresh supply is admitted to the cylinder through the opening d, it will move the piston back again. In this way, by alternately admitting steam at one end and exhausting it from the other, the piston receives a reciprocating motion, which is communicated to the outside of the cylinder by a rod, R, which is called the piston-rod, which works air-tight through an opening in one of the cylinder-covers, or cylinder-heads, as they are usually called.

* In all ordinary locomotives, the cylinders are so placed that the head C through which the piston-rod works is behind, and the other head D in front. The two ends of the cylinder are therefore designated the front and back ends, respectively.

-^ .>.a o o « a is ^h Xt, J5 0) a) © a a q fl3o • eg jg «

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G. Eccentric.

L. Eccentric-Rod.

The Steam Engine. 5

Question 3. How is this reciprocating motion of the piston converted into rotary motion f

Answer. By connecting the end of the piston-rod R (fig. 2) by another rod, E, called a connecting-rod, with a crank, P, which is attached to a revolving shaft, S. It is apparent that if the piston B is moved in the direction shown by the dart R, a rotary motion will be given to the crank in the direction of the dart N. When, however, the crank reaches the position shown by the dotted lines in fig. 5, it is plain that a force applied to move the piston in either direction will no longer produce a rotary movement of the crank and shaft. The same thing will occur when the crank is in the opposite position, shown by the full lines. These two positions are called the dead-points of the crank.

Question 4. How is the crank of an ordinary steam engine carried past the dead-points ?

Answer. Stationary engines are usually provided with a large and heavy wheel, called a fly-wheel (F F, fig. 2) which is attached to the shaft S. This wheel receives a sufficient amount of momentum from the crank, while the latter is moving from one dead-point to the other, to carry it past those points.

Question 5. How is the steam admitted to and exhausted from the cylinder f

Answer. It is admitted through two channels, c, d, fig. 2, called steam-ways, cast in the cylinder. These ways terminate in a smooth flat surf ace, ff called the valve-seat. Their openings in the valve-seat are called steam-ports. Between them is another port or cavity, g, called the exhaust-port, which communicates with the open air. The form of these ports is long and narrow, as shown in fig. 4, which represents a plan of them. Over these ports a valve, V, called a slide-valve, usually made of cast iron, with a cavity, H, on its under side, is fitted so that by moving it backwards or forwards it will alternately cover and uncover the two steam-ports. The valve and valve-seat are inclosed in a sort of box, II, fig. 2, made of cast iron, called a steam-chest, into which steam is admitted from the boiler by a pipe, J. When the valve is in the position represented in fig. 2, the front steam-port is uncovered and the steam is admitted to the front end of the cylinder, and thus forces the piston towards the back end. If, when the piston reaches the back end, the valve be moved into the position shown in fig. 3, the back steam-port will be uncovered and steam will be admitted to that end of the cylinder. At the same time it will be observed that the aperture of the front steam-port c and that of the exhaust-port are both covered by the cavity in the slide-valve, so that the steam which was admitted to the front end of the cylinder can escape through the steam-port c into the exhaust-port, and thus into the open air. In this way, by moving the valve alternately back and forth, steam is simultaneously admitted first to one end and exhausted from the other, and vice versa.

Question 6. How is the slide-valve moved so as to admit and exhaust the steam at the right time ?

Answer. This is done by what is called an eccentric, which is a circular disc, G (fig. 6), the axis of which is not in the centre. The outside of the eccentric is embraced by a metal ring, KK, made in two halves, called an eccentric-strap. The eccentric is attached to the shaft by screws or keys, and revolves with it and

The Steam Engine, 7

inside of the eccentric-strap. To the latter is also attached a rod, L, called an eccentric-rod. It is obvious from fig. 6 that if the eccentric revolves inside of the strap it will impart a reciprocating motion to the rod L. The eccentric, G, strap, K, and rod, L, are represented in fig. 2. Before describing their operation, or rather their connection with the valve V, it is necessary to understand that usually the valve-seat is placed on top of the cylinder, in which position it is difficult to connect the eccentric-rod with the valve. For convenience, therefore, what is called a rocker, rr, is placed between the cylinder and the main shaft of the engine. This rocker has two arms attached to a shaft, s, and the two arms have a vibratory motion about it, as indicated by the dotted lines. The eccentric-rod L is attached by a pin to the lower arm of the rocker, and the valve is connected to the upper arm by the rod M, called the valve-stem, or valve-rod. It is obvious that as the shaft S and eccentric G revolve, a reciprocating or vibratory motion will be given to the rocker, which will be communicated to the valve by the valve-stem ; and it is only .necessary to fix the eccentric in the proper position on the shaft, in relation to the crank and piston, to give the valve the required motion for admitting and exhausting the steam to and from the cylinder at the right time.

Part II. The Eobces Of Air Axd Steam

Question 7. What is meant by the pressure of the air f

Answer. It is the pressure exerted "by the weight of the air on every point with which it is in contact. The globe of the earth is surrounded by a layer of air about 50 miles thick, and, like every other substance, the air possesses weight, and hence presses upon every object with which it is in contact.

Question 8. How can it be shown that the air possesses weight ?

Answer. By weighing a flask when it is filled with air, and again when the air is exhausted from it. In the latter condition the weight of the flask will be found to be sensibly less than it was when full of air, showing that the air which the flask contained when it was first weighed increased its weight.

Question 9. Why do we not feel this pressure on our bodies ?

Answer. Because the air surrounds us on all sides, and presses just as much in one direction as it does in another, so that the pressures in different directions just balance each other, or are in equilibrium; but if you disturb this balance, for example, by sucking the air from a tube closed at one end, it will cling to your tongue; or if you take a thick piece of leather under ordinary conditions it will not adhere to anything, but if it be thoroughly wet and pressed hard against the surface of a smooth stone, so as to force out the air from under it, the stone, as nearly all school-boys know, can be lifted up if a string is attached to the leather ; or if the air be sucked out of a tube, one end of which is inserted in a liquid, the latter will be forced up the tube. These phenomena are due to the pressure of the atmosphere in the first case on one side of the person's tongue, pressing it against the mouth of the tube ; in the second, to the same pressure on the top of the leather, causing it to adhere to the stone ; and in the last, to the weight of the air pressing on the surface of the liquid, forcing it into the vacuum in the tube.

Question 10. What is the amount of the pressure of the atmosphere, and how is it measured ?

Answer. It is usually measured by the pressure on one square inch of surface, which at the earth's surface is 15 pounds.* If, for example, we have a cylinder, A, fig. 7, with an air-tight piston, B, fitted to it whose area is just one square inch, if we exhaust the air through the tube G from the cylinder above the piston, the air will press against the under side of the piston so that, if no power is required to overcome its friction in the cylinder, the pressure of the air will raise a weight of 15 pounds. The pressure of the air varies, however, as you ascend or descend from the surface of the earth, because as you go up on a mountain or in a balloon the layer of air above you becomes thinner, and, therefore, its weight and consequent

*In common practice it is generally taken at 16 lbs. per square inch, but the average atmospheric pressure is more accurately 14.7 pounds.

Fig 7 m Scale } pressure are diminished ; and as you descend, as in a deep mine, the layer is thicker, and its pressure consequently greater.

Question 11. What is steam f

Answer. Steam is water changed by means of heat into a gas. At every temperature there is formed from water, on its surface, vapor of which the clouds are formed at all seasons of the year. This change of water into vapor, or evaporation of water, takes place at low temperatures only on its surface, however. But if we heat water in a vessel to a temperature of 212 degrees Fahrenheit, then the inner particles of the mass of water (lying on the heating surface of the vessel) are changed into steam, and rise to the surface in bubbles, which is the phenomenon we call boiling. It must not be imagined, however, that the visible cloud which escapes from a kettle or the exhaust-pipe of a steam engine is true steam. It is rather small particles of water, into which the steam has condensed through contact with the cold air. True steam is invisible, as we may observe near the mouth of a kettle or the exhaust-pipe of an engine from which we know it is escaping.

Question 12. If water is heated in an open vessel what occurs?

Answer. It continues for some time to increase in temperature, and the evaporation becomes more and more rapid. At length bubbles of vapor break out and reach the surface, and the process of boiling or ebullition has begun. When this takes place the temperature of the water ceases to rise, and it remains stationary until all the water has boiled away, the only difference being that if the supply of heat be very great the process is very rapid, and if the supply of heat be small the process is very slow. The point at which ebullition commences is called the boiling-point.

Question 13. On what does the boiling-point depend?

Answer. Chiefly on the pressure on the surface of the water, but to some extent upon the purity of the water. Thus, boiling, which takes place at 212 degrees under the ordinary atmospheric pressure, in lighter air, as on higli mountains, takes place at a much lower temperature than on lowlands, and so water boils in a glass tube from which the air has been exhausted by the warmth of the hand, that is, at 92 degrees.

Question 14. What is the pressure of steam which escapes from boiling water in an open vessel?

Answer. It is exactly equal to the pressure of the atmosphere in which it is boiled. Ordinarily this is 15 lbs., and the boiling-point 212 degrees ; but if we go up on a mountain where the atmospheric pressure is only 10 lbs. per square inch, the water will then boil at a temperature of 193.3 degrees, and the steam which escapes will have the same pressure as the atmosphere, or 10 lbs. per square inch. On the other hand, if we could go down into a mine where the atmospheric pressure was 20 lbs. per square inch, the water would not boil until it was heated to 228 degrees, and the pressure of the escaping steam would then be 20 lbs. per square inch.

Question 15. If water is boiled in an enclosed vessel like a covered tea-kettle or a steam boiler, what occurs ?

Answer. The steam rises and fills the space above the water, and, if it cannot escape, increases in pressure. The temperature of both the water and the steam rises with the pressure, and will continue to do so as long as the heat is increased, or until the steam can escape or the vessel is exploded. The boiling point also rises as the steam pressure increases.

Question 16. Is there any pressure which corresponds to the temperature of steam and water ?

Answer. Yes. There is a fixed pressure for every temperature, when steam is in contact with water, and its pressure cannot be increased or diminished without at the same time heating or cooling the water, and the higher the temperature of the water the greater will be the corresponding steam pressure. Thus water at 212 degrees produces steam with a pressure equal to that of the atmosphere ; at 240 degrees the steam will have a pressure of 25 lbs., or 10 lbs. more than the atmospheric pressure ; at 281 degrees a pressure of 50 lbs. ; and at 328 degrees, 100 lbs. As this relation of pressure to temperature is fixed, if we know the one we can tell the other. This is true, however, only where the steam is in contact with water, when it is called saturated steam. If it is separated from water it may be heated to a higher temperature, and is then called superheated steam.