PART XXVII.

RUNNING LOCOMOTIVES.

QUESTION 473. _Before starting the fire in a locomotive, what must be observed?_

_Answer._ It must always be noticed, before kindling the fire, whether the boiler has the requisite quantity of water in it; that all cinders, clinkers and ashes are removed from the grates and ash-pan; that the grates and drop-door are properly fastened, and that the throttle-valve is closed and the lever secured. Locomotive boilers are sometimes seriously injured by building a fire in them when there is no water in the boiler. In filling a boiler it must be remembered, however, that when the water is heated it will expand, and that when bubbles of steam are formed they will mix with the water and thus increase its volume, so that after the water is heated its surface will be considerably higher than when it is cold.

QUESTION 474. _How should the fire in a locomotive be started?_

_Answer._ It should be started very slowly, so as not to heat any one part suddenly. Probably the greatest strains which a locomotive boiler has to bear are those due to the unequal expansion and contraction of its different parts. When the fire is started, of course the parts exposed to it are heated first, and consequently expand before the others. Now, if the fire is kindled rapidly, the heating surfaces will become very hot before the heat is communicated to the parts not exposed to the fire. Thus the tubes, for example, will be expanded so as to be considerably longer than the outside shell of the boiler, and therefore there will be a severe strain on the tube-plates, which will be communicated to the fire-box, stay-bolts, braces, etc. The inside plates of the fire-box will also become much hotter than those on the outside, and as it is rigidly fastened to the bar to which both the inside and the outside shells are fastened at the bottom, its expansion will all be upward, which thus strains the stay-bolts in that direction. As the motion due to this expansion is greatest near the top of the fire-box, the top stay-bolts are of course strained the most, and it is those in that position, as has already been pointed out, which are the most liable to break. When steel plates are used the expansion or contraction often cracks them, and sometimes, hours after the fire is withdrawn from the fire-box, the inside plates will crack with a report like that of a pistol. It is therefore very important both to heat and cool a locomotive boiler very slowly, and the fire should always be kindled several hours before the engine starts on its run.

QUESTION 475. _What should be done when the locomotive leaves the engine-house and before the train is started?_

_Answer._ Before leaving the engine-house the cylinder cocks should be opened, so that all the water or steam which is condensed in warming the cylinders can escape. Before the engine is started from the engine-house the bell should be rung and time enough allowed for any workmen employed about the engine to get out of the way. This rule must be scrupulously obeyed under _all circumstances_, and a locomotive should _never_ be started without first giving such a signal. Without it there is always danger that some one about the engine will be hurt or killed. While running from the engine-house to the train the runner should observe very carefully the working of all the parts of his engine, and as far as possible see that they are in good working condition. The fireman should stay on the tender to handle the brake, as may be necessary, and should assist in coupling the tender to the first car of the train. The junction with the train, especially when it is a passenger train, should be made very gently, as otherwise passengers may be injured by the shock. Before starting the runner should see _himself_ that the engine and tender are securely coupled together, and the latter to the train, that the frictional parts are properly lubricated, as explained heretofore, that the fire is in good condition and that the requisite quantity of steam has been generated. If the steam is too low, the blower is started, which stimulates the fire.

QUESTION 476. _When the train is ready, how should the engine be started?_

_Answer._ After the signal to start is given by the conductor, the runner also gives a signal by either ringing the bell or blowing the whistle. The latter should, however, be used, especially at stations, as little as possible, on account of the risk of frightening horses and the shock which it produces on persons who are unaccustomed to hearing it, or are suffering from any nervous disorder. After giving the requisite signal, the runner places the reverse-lever so that the valve will work either in full gear or very near it. He then opens the throttle _slowly_ and _cautiously_ so as to start the train gradually. If the train is a very heavy one, it is best to back the engine so as just to “take up the slack of the train,” that is, to push the cars together so that there will be no space between them and thus compress the car draw-springs. When the cars stand in this way, those at the front end of the train are started one after another, which makes the start easier than it would be if it were necessary to start them all at once. If the throttle is opened too rapidly, the driving-wheels are apt to slip, but with a very heavy train, even with the greatest care, this is liable to occur. If the train can not be started otherwise, the rails must be sanded by opening the valves in the sand-box. As little sand should be used as possible, because the resistance of cars running on sanded rails is greater than on clean rails, and thus the train is more difficult to draw after it reaches the rails to which sand has been applied. Thus the difficulty to be overcome may be increased by the means employed to overcome it.

While the train is slowly set in motion the fireman and runner must ascertain by watching whether the whole train moves together, and that none of the couplings are broken in starting, and also whether any signal is given to stop, as is sometimes necessary after the train has started. On leaving the station he should observe whether all the signals indicate that the track is clear and that the switches are set right, and also look out for obstructions on the track. The train should always be run slowly and cautiously until it has passed all the frogs, switches and crossings of the station yard, and not until then and when the runner has seen that everything is in order should he run at full speed. As the engine gains in speed the reverse lever should be thrown back and nearer the centre of the quadrant or sector, so as to cut off “shorter.”

QUESTION 477. _After the engine is started, how can it be run most economically?_

_Answer._ The advantage of using steam expansively has already been explained in Part V.; it is more economical to use steam of a high pressure which is done by keeping the throttle-valve wide open, and then regulating the speed by cutting off shorter--that is, expanding it more. If the speed is reduced by partly closing the throttle-valve, the steam is wire-drawn and, as was shown in answer to Question 59, it then produces much less useful effect than it would if it was admitted into the cylinder at full boiler pressure.

It is found, however, that in many cases if the steam is cut off very short the final pressure when it escapes is so low that it does not produce blast enough to stimulate the fire, and therefore the boiler will not make enough steam. This is more liable to occur with engines which have small than with those which have large boilers, or when the boilers are in bad condition or the fuel is of poor quality. When it does occur it is necessary to work steam during a longer portion of the stroke, so as to increase the final pressure when it is exhausted and regulate the speed with the throttle-valve. Of course this is very wasteful, but it is often the best which can be done and pull the train.

There is also another practical difficulty in using steam of a high pressure and running with the throttle wide open and regulating the speed with the reverse lever alone. The link motion, as has already been explained, will not be effective in cutting off at a point below about one-quarter of the stroke. Now it often happens, even when cutting off at that short point, with light trains on a level or slightly descending grade, that the speed will be too great if the throttle is wide open and with full steam pressure in the boiler. When this is the case, it is absolutely necessary to reduce the speed either by partly closing the throttle, or reducing the pressure in the boiler. Undoubtedly if valve-gear for locomotives was so constructed that steam could be cut off effectively at a shorter point of the stroke, it would result in increased economy in the use of steam.

The runner should aim to run at as nearly uniform speed as possible, and in order to do so should divide the distance between stopping points and the time given for running it into as small divisions as he conveniently can, so as to be able to tell as often as possible whether he is running too fast or too slow, and thus travel over the shorter spaces in corresponding periods of time.

QUESTION 478. _How should the boiler be fed?_

_Answer._ The feeding of the boiler should if possible be continuous, and the quantity of water pumped into it should be adjusted to the amount of work which the engine is doing. Ordinarily one pump is more than sufficient for feeding the boiler, so that usually only the one on the right side of the engine, where the runner stands, is used. The flow of the water is regulated by partly opening or closing the feed-cock. The injector is commonly used only when the engine is standing still, when the pumps will not feed. In feeding the boiler it must be seen that the water is neither too high nor too low. If it is too low there will be danger of overheating the crown-plates or even of an explosion; if it is too high, the steam space in the boiler is diminished unnecessarily, and will cause the water to rise in the form of a spray, and thus be carried into the cylinders with the steam, or the boiler will _prime_ or _foam_, as it is called. This water, if it collects in the cylinder as already explained, may by the concussion produced by the motion of the piston break the cylinder.

QUESTION 479. _What is the cause of priming in a boiler?_

_Answer_. It is often caused by the difference in temperature and pressure in the water below and the steam above. Thus, if we have a boiler in which the water is heated to a temperature due to 100 lbs. effective pressure, or 338 degrees, and we then open the throttle-valve suddenly, so as to relieve the pressure on top of the water, there will at once be a rapid generation of steam in the water which will rush to fill the space from which the steam has been drawn. This newly generated steam will be formed at the hottest part of the boiler first, that is, next to the heating surface. It will therefore happen that as soon as the pressure is relieved, bubbles of steam from all parts of the heating surface of the boiler will flow to the point at which the steam escapes. The motion of these bubbles will be so rapid that large quantities of water will be carried with them. The same thing will also occur if the heat of the water is increased very rapidly. The water will then become hotter than the temperature due to the pressure of the steam above it, and consequently there will be a rapid formation and escape of bubbles of steam from the water, which will thus have the same effect as they would have if the steam pressure was reduced.

The amount of water carried up with the steam is increased if the escape of the latter is obstructed in any way, owing to imperfect circulation of water in the boiler, or by floating impurities, such as oil, on the surface. When this condition of things exists, the ebullition is, as it were, convulsive, and the water is thus carried up with the steam when it escapes. Priming is also probably due in some measure to the flow of steam over the surface of the water to the point of outflow,[108] carrying particles of water with it just as a high wind will, when blowing over the crests of the waves of the sea.

[108] Wilson on Steam Boilers.

When steam is drawn, as it usually is in locomotives, from the top of the dome to which the safety-valves are attached, the tendency to prime is very much increased when they are blowing off, so that some engineers advocate the use of two domes, from both of which the supply of steam is sometimes drawn, and in other cases the safety-valves are mounted on one, and the steam-pipe is placed in another dome. Whenever the safety-valves begin blowing off steam, the pressure in the boiler should be reduced as soon as possible, not only because when they are blowing off it tends to produce priming, but because the steam which escapes from them is wasted. The pressure can be most economically reduced either by increasing the amount of water which is fed into the boiler or by opening the heater cocks and allowing the steam to escape into the tank and thus warm the water. If the boiler is too full, the former method cannot be employed, and in heating the water in the tank the runner must be careful not to get it too hot, because in that case neither the pumps nor the injectors will work satisfactorily, and the paint on the tenders is also liable to be blistered and destroyed by the heat. By feeling the tank with the hand it can soon be discovered whether the water is too hot. If the steam pressure cannot be reduced in any other way, the furnace door must be partly opened.

The use of muddy water will also sometimes cause a boiler to prime. It is probable that priming is sometimes due to the formation of foam on the surface of the water, and therefore all priming is often called foaming; whereas it is thought that often a boiler will prime when the water does not foam. More accurate information regarding the priming of boilers is, however, much needed, as many of the phenomena have thus far not been satisfactorily explained. The principal causes of priming in ordinary practice are, however, undoubtedly owing to defective circulation, too little steam room, impure water, or too much water in the boiler.

QUESTION 480. _How can it be known whether an engine is priming, and what should be done to prevent it?_

_Answer_. The priming of a boiler can be known by the white appearance of the steam which escapes from the smoke-stack and the cylinder cocks. Dry steam always has a bluish color. When an engine primes or works water into the cylinders, it is usually indicated by a peculiar dead sound of the exhaust, which from this cause loses its distinctly defined and sharp sound. This can be observed best when the furnace door is opened. It is also indicated by the discharge from the gauge-cock, as the water which then escapes from the lower cocks is mixed with steam, or, as runners say, is not “solid,” and the steam from the upper cocks is not clear, but mixed with water. To use a phrase employed by practical men, the priming or foaming of the boiler may be known by the “flutter” of the gauge-cocks. As soon as there are any indications of priming, foaming, or that water is working into the cylinders, the cylinder cocks should be opened at once, otherwise the cylinders, cylinder heads or pistons may be broken. The throttle-valve should be either partly or entirely closed. When the latter is done the foaming will in most cases cease for the time, so that the runner can tell how much solid water there is in the boiler. If he finds that the boiler has too much water in it? it is best to shut off the pumps, and in many cases the blow-off cock is opened. The latter is, however, attended with some danger, because if any obstruction should get into the blow-off cock, or it should stick fast, so that it could not be closed, all the water would escape from the boiler, and with a heavy fire in the fire-box there would be great danger of overheating, and thus injuring the boiler or of “burning” it, as it is ordinarily termed.

A much better method of affording relief in such cases is to place what is called a _surface-cock_ in the back end of the fire-box, about half way between the upper and lower gauge-cocks. With such a cock, the water can be blown off from the surface instead of from the bottom. As foaming or priming is often caused by oil, or other floating impurities on the surface, they can be blown out of the boiler with this arrangement, whereas, if the water escapes from the bottom of the boiler, the floating impurities will always remain after it is blown off. A perforated pipe, which extends for some distance along the surface of the water inside the boiler, is sometimes attached to the surface-cock, so that the water which is blown off will be drawn from a number of points along the surface.

If the steam is rising rapidly when foaming begins, it will be well to cool the boiler off by opening the furnace door part way. This means of relief should, however, be used as little as possible, because there is always danger of causing the tubes or other parts of the boiler to leak, by either heating or cooling suddenly or rapidly. If the engine primes when there is but little water in the boiler, and at a time when the steam is rising rapidly, it may sometimes be remedied by increasing the amount of feed-water, and thus partly cooling the water inside. The use of pure water, careful firing so as to keep the steam pressure regular, feeding the boiler so that the level of the water will be nearly uniform, and then starting the engine carefully, that is, opening the throttle-valve gradually, are the most effective means in practice of preventing a locomotive boiler from priming.

QUESTION 481. _What is the economical effect of priming on the consumption of fuel in locomotives?_

_Answer._ It causes a great waste of heat, first by the escape of that contained in the hot water which passes through the cylinders and which does no work, and second, when steam is mixed with a great deal of water, it will not flow either to or from the cylinders as quickly or easily as dry steam will. Consequently the initial pressure on the piston, if the engine is running even moderately fast, and is cutting off short, will not be so great as it would be if dry steam was used. Wet steam is also more difficult to exhaust from the cylinder than that which is dry, and therefore the back pressure on the piston is greater when the boiler primes than when dry steam alone is used.

QUESTION 482. _When running on the open road, what should the locomotive runner observe?_

_Answer._ Either he or the fireman should _constantly_ watch the track in front of them, and also observe, from time to time, whether the train of cars, especially if it is a long one which he is handling, is in good condition. HE MUST OBSERVE EVERY SIGNAL SCRUPULOUSLY, AND SHOULD NEVER PASS ONE UNTIL HE IS SURE THAT HE IS AUTHORIZED TO DO SO. The well-known maxim, “be sure you are right; then go ahead,” should be changed for locomotive runners to, DON’T GO AHEAD UNTIL YOU ARE SURE YOU ARE RIGHT, AND WHEN IN DOUBT ALWAYS CHOOSE THE SIDE OF SAFETY. In running through curves, the speed of the train should always be moderated in proportion to the sharpness of the curve, and before reaching it. In running through curves, the tendency of the train is to continue in a straight line, and there is thus danger of running off the track. The higher the speed, of course, the greater is the resistance which is required to prevent the train from running in a straight line, and consequently the greater is the strain which is thrown on the flanges of the wheels and on the rails and axles. In running through curves, it is also impossible, usually, to see further than a short distance ahead, and therefore, if the train is running very fast, it cannot be stopped in time, should there be any obstruction or danger on the track.

QUESTION 483. _What precautions should be observed in running over steep grades?_

_Answer._ On approaching an ascending grade the runner should see that the fire is in good condition, and as much coal should be put on it as can be burned to advantage. He should also fill the boiler as full of water as he safely can, without danger of priming, and should heat this water as hot as possible without blowing off steam at the safety-valves. The object of this is to have a supply of water already heated before reaching the grade. If, as often happens with a heavy train, the boiler will not make as much steam as the engine consumes, if there is a large supply of hot water in the boiler it can be used as a reserve, should it be necessary to do so, without danger of injury to the boiler. If there was so little water in the boiler that it would be dangerous to allow it to get lower, then it would be necessary to feed cold water as rapidly as the hot water escaped in the form of steam. It is often impossible to heat all this cold water as fast as it is pumped into the boiler, without reducing the steam pressure until there is then not sufficient power to pull the train. If, however, there is a supply of hot water in the boiler, at the critical point on the grade, where the engine is most liable to fail, the pump can be partly shut off, and thus less water will be pumped into the boiler, and the steam pressure be maintained without danger. Undoubtedly it is better to feed locomotive boilers uniformly, if that is possible, but it often happens that a reserve supply of hot water in the boiler enables an engine to pull a train up the most difficult place, whereas, without such a supply, the locomotive would stick fast. As the capacity of locomotives is rated on nearly all roads by the number of cars they can “pull up the hill,” of course whatever aids them at the critical point increases their capacity. It is this fact which gives engines with large boilers so much advantage over those with small ones.

In running up steep grades, allowance should always be made for the effect of the inclination of the track upon the position of the water surface in the boiler, and also the fact that as soon as the throttle-valve is closed, and steam shut off, the surface of the water will be considerably lower than when the engine was working hard. On a grade of 50 feet to a mile, the front end of the tubes of an ordinary locomotive would be about 1³⁄₄ inches higher than the back end of the crown-sheet. If, then, on working hard up such a grade, it is succeeded by another of equal descent, the front ends of the tubes would be 1³⁄₄ inches _lower_ than they were while coming up, so that if the back end of the crown-sheet was covered with 1³⁄₄ inches of water just before reaching the top, it would be exposed to the fire as soon as the engine reached the descent. This exposure would be dangerous, because not only would the water be 1³⁄₄ inches lower over the crown-sheet, but it would fall considerably more when the throttle-valve was closed. These considerations will show the danger of running the water too low while ascending steep grades.

In pulling trains up steep grades, especial caution should be exercised to prevent any of the cars from breaking loose from the train, because such an accident may cause great disaster.

As soon as the engine reaches the top of the grade, the fireman should oil the main valves, because it can only be done when steam is shut off, as the oil will not run into the steam-chest when there is a pressure of steam in it; and as the valves are always subjected to the severest wear while pulling up a steep grade, the valves and valve-faces are apt to become dry. As saturated steam to some extent prevents valves from cutting, it is not so important that they be lubricated while the engine is working with steam, but as soon as steam is shut off they should be oiled, otherwise there is danger of their being injured by their friction on the valve-seats.

In running down grades, the runner has the greatest possible cause for using every precaution, because not only is the train much more difficult to control, but usually frequent sharp curves prevent a view of the track for any considerable distance ahead. He should, therefore, watch the track in front of him with the greatest vigilance, so as to be ready to give the requisite signals to the brakemen to apply the brakes, or, if the engine and train are provided with continuous brakes, to apply the latter, or even reverse his engine, in case of danger.

QUESTION 484. _How should an engine be run past those stations where the train does not stop?_

_Answer._ The speed of the train should be slackened in passing stations, especially if a clear view of the track and switch signals can not be obtained at some distance before reaching the station. There is always a possibility that the switches may be turned wrong, or that there may be some obstruction on the track at stations, so that some caution should be exercised in running past them. The proper signal, either by the whistle[109] or the bell, should be given on approaching stations, and also at all common road crossings.

[109] The methods of giving signals vary so much on different roads that no general direction that will suit all cases can be given.

QUESTION 485. _What must be done on approaching a draw-bridge or a crossing of another railroad at the same level?_

_Answer._ In many of the States it is provided by law that all trains must come to a _dead stop_ before crossing a draw-bridge or another railroad at the same level. Whether such a law exists or not, the rule should always be observed. After coming to a stop, the train should under no circumstances be started until the signal has been given to start the train by the signal-man at the bridge or crossing. A runner should _never assume_ that the signal has been given, nor take another person’s word for it, but should see and know it himself. In some conditions of the weather and with the light falling on a signal in certain directions, it is sometimes difficult to determine its color or form. If there is any doubt about it, the testimony of another person should always be sought. There is good reason for believing that color-blindness, that is, an incapacity for distinguishing one color from another, is a much more common infirmity than is usually supposed. It is certain, too, that people who ordinarily distinguish colors very accurately are subject to color-blindness in certain conditions of health, and that it is sometimes the result of overwork or great weariness; and a case is recorded of a person who was always color-blind after a debauch. There are, therefore, good reasons why a locomotive runner should not always place too implicit confidence in what he “sees with his own eyes,” but if he has any doubt, he should take the “benefit of the doubt,” which should always lead him to take the side of safety.

QUESTION 486. _How should the engine and train be managed in running into a station?_

_Answer._ First of all when running into a station when the train stops, the speed must be checked so that the train will not enter with very great momentum. Therefore, at a distance varying from one to three-quarters of a mile, according to the nature of the grades and track, the steam should be shut off, so that the speed will be reduced so much that the train under any circumstances will be under full control. It is always better to enter a station at too low a speed than to run in too fast, because if it is necessary, more steam can always be admitted to the cylinders to increase the speed before coming to a stop; whereas it is not so easy to stop the train if it is running too fast, and it becomes necessary to check it before entering the station. This will sometimes be necessary, because it may readily happen through negligence or accident at stations that in switching cars one or more may be left standing wholly or partly on the track, which the arriving train must run over, in which case a collision with its terrible consequences may be unavoidable.

When a train is equipped with continuous brakes, the control which they usually give to a locomotive runner over the train is so great that he is apt to approach stations, crossings or draw-bridges at a high rate of speed, and rely on such brakes to stop the train. This practice is always attended with great danger, because if it was found, on getting near to the station, crossing or draw-bridge, that the track was not clear, and that it was obstructed by a car or train, or the draw was open, if the runner should attempt to apply the brakes and from some cause they should fail to work, as sometimes occurs, then a collision or other disaster would be inevitable, because it would be impossible to stop the train with the ordinary hand brakes. For this reason a locomotive runner should always approach such places cautiously and with his train under sufficient control, so that if he finds there is danger ahead he can stop the train with the ordinary means, or at the worst by reversing the engine. Continuous brakes should always, excepting in cases of imminent danger, be applied gradually, so as not to check the cars with a jerk or too suddenly. The practice of opening the cock which admits air to atmospheric brakes suddenly, and then turning it back again as quickly, is almost sure to produce disagreeable and dangerous shocks to the cars. The cock should be opened gradually, so as to check the cars slowly at first.

QUESTION 487. _What must be attended to when running a locomotive at night?_

_Answer._ As soon as it begins to grow dark, the head-light must be lighted and properly trimmed, and the proper lamp signals placed in front of the engine, if the rules of the road require the display of such signals. A lamp should always be placed in the cab, so as to throw its light on the steam-gauge, but not into the runner’s face, because he is unable to see distant signals so well if his eyes are exposed to the glare of a light near him.

At night, as objects which are passed can not be seen distinctly, it is more difficult to tell the speed at which an engine is running than it is in the day time. A runner should therefore consult his watch frequently, and by counting the revolutions of the wheels, which he can do by the sound of the pump valve or other part of the machinery, he can tell from the rule given in the answer to Question 438 the speed at which the locomotive is running. From this rule a table can easily be constructed for an engine with any size of driving-wheels, showing the speed for any given number of revolutions per minute. It will be a good exercise for a young locomotive runner to construct such a table, which will be found very convenient for reference if placed in a conspicuous place in the cab.

QUESTION 488. _What must be attended to in very cold weather?_

_Answer._ Great care must be exercised to prevent the water in the pumps, pipes and in the tender from freezing. If it does it will be almost certain to break the pump or burst the pipes. To avoid this the heater cocks must be opened so as to keep the water in the tender warm. In excessively cold weather the engine should be run with greater caution than at other times, as iron is then more brittle, and also more liable to break, owing to the frozen condition and consequent solidity of the track.

QUESTION 489. _In running a locomotive in severe snow or rain-storms, what should be observed?_

_Answer._ Whenever it snows the pilot or cow catcher should be covered with boards, or, better still, with sheet iron, so as to act like a snow plow. Brooms made of steel wire should be placed in front of the front wheels of the engine, so as to sweep the snow from the rails. The front damper on the ash-pan should be kept closed so as to exclude the snow from the ash-pan, which would soon fill it up, and in this way obstruct the draft. If the fall of snow is very heavy or it blows into drifts, the train must of necessity run very slowly, and even if a part of the track is clear of snow, it is unsafe to run fast on it, as there would be danger of throwing the engine off the rails if it should run into a heavy drift at a high speed.

In severe rain storms bridges, culverts and such portions of the track as are liable to be washed away should be approached cautiously, especially at night. In both snow and rain-storms, and also in fogs, great caution is required, owing to the difficulty of seeing signals.

QUESTION 490. _What is meant by a reserve engine or_ “_helper?_”

_Answer._ A _reserve engine_ is a locomotive which is not employed in hauling a regular train, but is kept as a “reserve” to go to the help of an engine which may be compelled to stop on account of an accident of any kind, or to assist engines in moving trains up heavy grades, or is used in clearing away a wrecked train, rebuilding bridges or other structures.

QUESTION 491. _What must be observed in running a reserve engine?_

_Answer._ As no special arrangements are usually made in preparing time-tables[110] for the running of reserve, or as they are usually called by railroad men, “_wild_” engines, it may very probably happen that it will be called upon to assist other engines when the road is not clear, and therefore its runner must constantly be on the look-out for signals to stop, which are often given suddenly. He must switch off with special caution in order to be sure to keep out of the way of regular trains running in the opposite direction on the same track. When he reaches the train or place where the assistance of the reserve engine is needed, he must approach it _slowly_ and _carefully_, in order to avoid a violent shock. On the return from the assisted train, he incurs the same danger, and must pay close attention to any signal to stop made to him by any opposite train on the same track, and also on his part warn such trains by the proper signals.

[110] A _time-table_ is a table which gives the time when each train shall arrive at the stations it passes, the stations at which it shall stop, and all the regulations by which it shall be run.

When a train is run with two engines, both in front of it, the forward one always takes the management of the train. The runner of the hind engine must be guided by the signals of the runner of the forward engine. In starting, the forward engine must be set in motion first and then the one behind it. In stopping, the steam must be shut off first in the hind engine. Likewise in decreasing the speed during the trip, the hind engine must first regulate the flow of steam. If these precautions are not observed the forward engine may easily be thrown from the track by the faster motion of the hind one.

When a train is assisted by a “helper” placed _behind_ the train, and therefore pushing it, the forward engine must likewise be set in motion first, and steam should be let on in the hind engine only after a signal has been given by the runner of the head engine. During the run both engines must move with the same speed.[111]

[111] Katechismus der Einrichtung und des Betriebes der Locomotive, by Georg Kosak.

QUESTION 492. _How should switching engines be managed?_

_Answer._ In pushing and switching the freight cars in the station-yard, they should be moved carefully and severe shocks must be avoided, as the cars, the goods with which they are loaded and the persons employed about them may be injured by violent concussions. The runner must also follow the instructions of his superior _strictly_ and _cheerfully_, and should examine patiently and observe with discretion the suggestions of employes who are not his superiors.

In this service it is also of special importance that the runner give a _distinct_ signal with the whistle or bell before every movement of his engine, in order to warn in time those who at such times often stand on the track in the way of the engine or cars, or the persons engaged in loading, cleaning or repairing the cars, and thus give them time to get out of the way.[112]

[112] Georg Kosak.

QUESTION 493. _In firing a locomotive, what are the most important ends to be attained?_

_Answer._ That which is of first and chief importance is to make steam enough, so that the locomotive can pull its train and “_make time_”[113]; second, it must make the requisite quantity of steam with the least consumption of coal, and third, with the least production of smoke, although the latter, independent of the economy of combustion, is considered of importance only with passenger trains. What is frequently lost sight of in considering this subject is the fact that with all locomotives it often happens that it is a matter of extreme difficulty to make enough steam to do the work required of the engines. When a freight train is struggling up a grade with a heavy train, or an express engine is obliged to make time under similar conditions, it often depends entirely upon the quantity of steam which can be generated in the boiler in a given time whether the engine will fail or not. In firing, therefore, the most important end to be aimed at is often simply to produce the largest amount of steam possible in a given time, even at the sacrifice of economy or by producing any quantity of smoke. Any means of economizing fuel or of smoke prevention, which reduces the steam-producing capacity of boilers, is therefore quite sure to be abandoned in time.

[113] The term _make time_ means to run at the speed indicated on the time-table.

QUESTION 494. _How can a boiler be made to produce the largest quantity of steam in a given time?_

_Answer._ By burning the greatest quantity of fuel possible on the grate in that time. This can be done by keeping the grates free from clinkers and the ash-pan from ashes, and then distributing the coal evenly over the grates in a layer six to twelve inches thick. The thickness of the layer which will give the best results will, however, vary with the quality of the fuel, and must be determined by experience. If the layer is too thick, not enough air will pass through it to burn the coal. If it is too thin, then so much air will pass through that the temperature in the fire will be reduced. The rapidity of combustion will also be promoted by breaking up the coal into lumps the size of a man’s fist or smaller. If fine coal is used it should be wet, otherwise it will be carried into the flues by the blast before it is burned or caked or even reaches the grate. Experience will indicate the amount of air which can advantageously be admitted above the fire in order to secure the maximum production of steam. The best size of the exhaust nozzles and the position of the petticoat pipe must also be determined by experience. It will usually be found, however, that if enough air is admitted above the fire to prevent smoke, it will reduce the maximum amount of steam which can be generated in a given time. The fire should also be fed regularly and with comparatively small quantities of fuel at a time, although if the feeding is too frequent there is more loss from the cooling effect which results from the frequent opening of the furnace door than is gained from the regularity of the firing. In this, too, a fireman must consult experience to guide him.

QUESTION 495. _How can a locomotive be fired with the least consumption of coal?_

_Answer._ Two systems of firing are practiced in this country, one known as the “banking system” and the other the “spreading system.” When the banking system is employed, the coal is piled up at the back part of the fire-box, as shown in fig. 218, and slopes down towards the front of the grate, where the layer of coal is comparatively thin and in an active state of incandescence. The heap of coal behind is gradually coked by the heat in the fire-box and the gases are thus expelled. Openings in the furnace door admit air which mingles with the escaping gases, which then pass over the bright fire in front, and are thus supposed to be consumed. When the “bank” of coal behind becomes thoroughly coked, it is pushed forward on the bright fire and fresh coal is again put on behind to be coked. This system of firing is practiced on some roads with good results, but it is doubtful whether it could be used successfully with coal which cakes and clinkers badly.

The spreading system is most commonly employed in the Western States, where the coal contains a great deal of clinker. When this is practiced, the coal is spread evenly over the whole of the grate in a thin layer, and its success and economy depend upon the regularity and evenness with which this layer of coal is maintained and the fire fed. The thickness of the coal must be adapted to the working of the engine. When it is working lightly, the layer of coal should be thin, but when the engine is pulling hard the layer of coal must be thicker, otherwise the violent blast may lift the coal off the grates. The success of this system, as was explained in answer to Question 388, depends upon the manner in which the thickness of the fire is regulated, on the admission of the proper amount of air above the fire, and on the frequency with which the fire is supplied with coal. When this system of firing is employed not more than two shovels-full of coal should be put into the fire-box at once, and if the engine is not working hard, one or even less will be sufficient. The firemen must, however, determine by experience the thickness of fire, amount of air which should be admitted and the frequency of firing which will give the best results in practice. Doubtless these will vary with different kinds of fuel and the construction of engines. Usually the greatest obstacle in the way of producing good results is the fact that firemen would rather “take things easy” than exercise that diligence and observation which will alone insure success in any occupation.

QUESTION 496. _How can smoke be most effectually prevented?_

_Answer._ The means of preventing smoke were very fully explained in answer to Questions 379 and 388. It may be said briefly that this can be done only by properly regulating the supply of air which is admitted to the fire. The means of doing this have already been explained.

QUESTION 497. _What method of firing is employed when anthracite coal is used?_

_Answer._ The spreading system alone is then used.

QUESTION 498. _How may the rules which firemen should observe when bituminous coal is used be briefly stated?_

_Answer._ 1. Keep the grate, ash-pan and tubes clean. 2. Break the coal into small lumps. 3. Fire often and in small quantities. 4. Keep the furnace door open as little as possible. 5. Consult the steam gauge frequently, and maintain a uniform steam pressure, and if necessary to reduce the pressure do it by closing the ash-pan dampers rather than by opening the furnace door.

QUESTION 499. _On arriving at a station where a train stops longer than a few minutes, what should the locomotive runner and fireman attend to?_

_Answer._ The runner should examine thoroughly all the parts of his engine, as has been heretofore explained. He should especially examine all the journals and wearing surfaces to see whether they are hot. This he can discover by feeling them. If any of them have become very much heated, they must be cooled by throwing cold water on them, and then thoroughly oiled. In oiling a hot journal mineral oil should never be used, as it is easily evaporated by the heat and then takes fire. Animal oil should therefore always be used on a hot bearing. The working parts should be thoroughly lubricated, as already explained.

The fireman should examine the tank and see whether it is necessary to take in a fresh supply of water. He should then examine the grates and ash-pan, and clean the cinders and clinkers from the former, and the ashes from the latter. Neglecting to clean the ash-pan may result in melting and destroying the grate-bars, and by obstructing the admission of air to the grates the ashes prevent the combustion from being as complete as it would be otherwise. With some kinds of fuel it is necessary to clean the tubes frequently, which must often be done at stations where the train stops.

During the stop, as thorough an inspection of the engine should be made by the runner and fireman as the time will permit; but any unnecessary waste of time must be avoided, and the firing should be so managed that nothing need be done about it during the halt at the station. On starting again the same precautions should be exercised as on making the first start.

QUESTION 500. _After reaching the end of its run, how should an engine be cleaned and repaired?_

_Answer._ Before reaching the last station the firing should be so managed that there will be as little fire as possible remaining in the fire-box at the end of the run. After the arrival the engine should be run over a pit which is usually provided for the purpose, and the fire should be raked out of the fire-box by dropping the drop-door if there is one to the grate, or turning the grate-bars edgewise, or withdrawing one or more of them if it is necessary to do so. In this way the fire will fall into the ash-pan, from which it can easily be raked. After all the fire is withdrawn the dampers and furnace door should be closed so as not to allow the cold air to cool the fire-box and tubes too rapidly.

In order to keep the boiler clean, that is as free as possible from sand, sediment or incrustation, it is necessary to blow it out frequently if the water which is used contains much solid or incrustating matter. With “bad water” the boiler should be blown out as often as possible. On some roads this is done after each trip. In blowing a boiler out, the blow-off cocks must be left open, and after all the water has escaped the engine should be left to stand until it is cooled off. If there is any considerable accumulation of mud or sediment the hand-holes at the bottom of the fire-box and the cover to the mud-drum should be taken off, and as much of the mud removed as can be scraped out through those apertures. A hose pipe attached to the hose of a force pump should then be inserted through these same openings, and a strong stream of water forced into the boiler. By this means much of the loose mud and scale will be washed out. The oftener this is repeated of course the cleaner can a boiler be kept. If a large amount of incrustation or mud has accumulated about the tubes, some or all of them must be taken out, so as to be able to remove the dirt.

After an engine is blown out, under no circumstances excepting absolute necessity should it be filled with cold water until it is entirely cooled off. It should be remembered that any sudden change of temperature in a boiler subjects it to very great strains and incurs the danger of cracking the fire-box plates, or causing the tubes to leak.

The tender should also be cleaned of the mud which settles in it from time to time, but it is not necessary to do this as often as it is to clean the boiler. All the plates and flues should have the soot which sticks to them thoroughly cleaned off.

Although the cleaning of the boiler and the grates is usually committed to a special set of men, yet the locomotive runner should examine them personally to see that it is properly done. He should pay attention to the condition of the grate, and see whether it is level and smooth. As soon as one or more of the bars are bent crooked, they usually burn out. If one of the bars is burnt out the fire falls through the hole that it leaves into the ash-pan, and then the fire under the grate will heat it red hot, and finally may melt every bar. Every grate-bar which is only a little damaged or bent must therefore be removed as quickly as possible and replaced with a new one.

As soon as the engine is run into the engine-house, all superfluous grease which has escaped from the wearing surfaces and the dust or mud which adheres to the engine should be wiped off with cotton waste or rags. This is usually done by men employed for the purpose. While they are doing this, they should examine every part thoroughly and observe whether it is in good condition, and if any defects are found they should be reported to the proper person whose business it is to have them repaired. As the faithfulness and skill of a fireman are often estimated by the good or bad condition of his engine, he should, if for no other reason, take pains to keep it clean and everything in as good condition as possible.

If the engine is taken to pieces in order to be thoroughly repaired, the runner, if he does not help to do this, should watch carefully the taking it apart and the putting it together again, as in this way he can become thoroughly familiar with the construction of the machine he runs.

QUESTION 501. _What precaution must be taken to prevent the water in a locomotive from freezing, if it is laid up?_

_Answer._ In very cold weather, if engines are laid up for any considerable time, no water must be left in the tender, boiler or any of the pipes. If, however, the engine must be soon used, and it is impracticable to let the water out of the boiler and tender, then, if exposed to the cold, a light fire must be kept in the boiler sufficient to make steam enough to warm the water in the tender. The water should, however, be drawn out of the pumps and the feed and supply pipes. This can be done by opening the pet-cocks, and closing the tender valves and uncoupling the hose, which will allow the water in the supply pipes to run out. By running the engine a few revolutions the pumps will then be emptied. The pipes and the pumps can also be prevented from freezing without uncoupling the hose if the tender valves are closed and the pet-cocks opened, and steam is then admitted into the supply pipes by the heater-cocks. This forces part of the water which is in the pumps out of the pet-cocks and warms the rest. This, however, requires constant watchfulness to prevent freezing, and in excessively cold weather, if the engine must lay up for any considerable time, it is always best to empty the pumps and pipes.