PART XXVI.

INSPECTION OF LOCOMOTIVES.

QUESTION 455. _What are the principal divisions of the work of operating or running a locomotive?_

_Answer._ They are: 1. Inspection and lubrication; that is, an examination of the parts to see that they are in good working order, and the application of oil to the journals and other parts subjected to wear. 2. Setting the engine in motion and starting the locomotive and train. 3. Management while running. 4. Stopping the engine and train. 5. Laying up. 6. Management in case of accident. 7. Cleaning the engine.

QUESTION 456. _When the locomotive is inspected, what should be especially observed about the boiler?_

_Answer._ In the first place, all new boilers should be tested by pressure before being used, and ALL boilers, whether new or old, SHOULD BE TESTED PERIODICALLY. The oftener the better. The ways of applying the pressure test are: 1, the cold-water test, that is, by filling the boiler with cold water and then forcing in an additional quantity with a force-pump so as to raise the pressure to that at which it is intended to test the boiler; 2, the warm-water test, by filling the boiler entirely full of cold water and then kindling a fire in the grate so as to warm this water. As water expands about one twenty-fourth in rising from 60 to 212 degrees, the rise in temperature will cause a corresponding increase in pressure; 3, by steam pressure.

If the latter method were not so commonly used, it would seem the height of madness to test a boiler--which is neither more nor less than an attempt to explode it--in the shop where it is built or repaired, and where the results of an explosion would be more disastrous and fatal than anywhere else, in order to see whether it will explode when put into service on the line of the road. The danger of explosion is also increased at such times by hammering and caulking at leaky rivets and joints.[106] It would seem, therefore, very much more rational to test boilers first by hydraulic pressure. For a first test this is preferable, because cold water will leak through crevices which would be tight when the boiler is heated, so that leaks can be more surely detected with cold than with warm or hot water. It is, however, doubtless true that boilers are often strained much more by the unequal expansion of the different parts than by the actual pressure. It is therefore thought that after the hydraulic test has been applied the second or warm-water test should be used. This can be easily done, as the boiler must be filled full of water for the first test. When the boiler is subjected to the test pressure, it should be carefully examined to see whether any indications of weakness are revealed. Any material change of form or any very irregular change of pressure is indicative of weakness. The flat stayed surfaces should be carefully examined by applying a straight edge to them before and after they are subjected to pressure, to see whether they change their form materially. One of the greatest dangers and most common accidents to locomotive boilers, as has been pointed out in a previous chapter, is the breaking of stay-bolts, to detect which, a locomotive runner and master mechanic should exercise constant vigilance. While the pressure is on, the outside surface of the boiler should be thoroughly examined with slight blows of a hammer, which will often reveal a flaw in the metal or a defect in workmanship. After the hydraulic and warm-water tests have been applied, the boiler should be emptied, and the inside examined carefully to see whether any of the stays and braces have been broken or displaced by the test. After this has been done, and not until then, should steam be generated in the boiler. In making the latter test it would doubtless be more safe to employ a pressure somewhat lower than that employed with the cold and warm water. There is great diversity of opinion regarding the maximum pressure which should be employed in testing boilers. It is doubtless true that a weak boiler might be injured and thus made dangerous by subjecting it to a very severe pressure, while without such a test it would have been safe. Recent experiments have indicated, however, that in most cases the ultimate strength of material is actually increased by subjecting it to a strain which even _exceeds_ the elastic limit, provided such a strain is imposed only a few times. Although no absolute rule can be given to govern all such cases, it is thought that for the hydraulic and warm-water tests, a pressure about 50 per cent. greater and for the steam test 25 per cent. greater than the maximum working pressure should be employed.

[106] Wilson on Boiler Construction.

Before old boilers are tested, they should be very carefully examined, both inside and outside, to see whether they are injuriously corroded. It is to be regretted that the insides of locomotive boilers are usually made so difficult of access that it is impossible to discover the extent and the effects of corrosion without the most careful examination. This is not possible without getting inside of the boiler. Whenever this can be done, a prudent locomotive runner should use the opportunity of inspecting the boiler of his engine himself, and not depend upon the boiler-makers who are employed for that purpose. He should remember that it is his life and not theirs which is exposed to danger by any weakness or defect in the construction of the boiler of the locomotive which he runs.

Before starting the fire in a locomotive, the fire-box should be carefully examined to see if there are any indications of leaks, which will often reveal cracked plates, defective stay-bolts or flues. If the latter simply leak at the joints, they can generally be made tight by caulking or the use of the tube expander. This is easily done when the engine is cold, but if not attended to may be very troublesome on the road. Leaks at other parts of the boiler should be examined, as they may reveal dangerous fractures.

It is of the utmost importance, both for safety and for economy of working, that boilers should be kept clean, that is, free from mud and incrustation. In some sections of the country, especially in the Western States, this is the greatest evil against which locomotive runners and those having the care of locomotives must contend. The cures which have been proposed are numberless, but that which is now chiefly relied upon is, first, the use of the best water that can be procured, and second, frequent and thorough washing out of the boiler.

QUESTION 457. _What sort of examination should be given to the boiler attachments?_

_Answer._ It should be observed whether the grate-bars or drop-doors of the grate are properly fastened, and whether the ashes have been cleaned out of the ash-pan, and also whether the fire is clean, that is, whether the grates are free from cinders or clinkers. The height of water in the boiler should be observed by testing it with the gauge-cocks and by noticing it in the glass gauge, if one of the latter is used. It is also well to blow out the sediment and mud from the latter before starting, and to see that the valves which admit steam and water to the glass are open. They should, however, be opened only a very short distance, so that only a small quantity of steam or hot water will escape in case the glass tube should be broken. The injector, if one is used, should be tested to see that it is in working order, and as soon as the engine starts out of the engine house both of the pumps should also be tested, in order to see whether they are in good working condition. The safety-valves should be raised, so as to be sure that they are not rusted or otherwise fastened to their seats. There is no part of a locomotive more liable to disorder than the steam gauge. For this reason it should be frequently tested, and whenever there is any indication of irregularity in its action it should be examined. As the wire netting on the smoke-stack often has holes cut into it by the action of the sparks, it should be frequently examined to see whether it is in good condition. It is also liable to be “gummed up,” especially if too much oil is used in lubricating the cylinders and valves. As soon as holes are cut into the netting there is danger that the sparks which escape will set fire to the combustible material near the track, and if the netting is gummed up the draft will be obstructed and the engine will not make steam. The gummy matter can often be removed by building a wood fire on top of the netting. In this way the oil in the gummy matter is burned up, which leaves a dry material which can then, at least to some extent, be beaten out of the netting.

QUESTION 458. _How can it be known whether the pumps are working well?_

_Answer._ Their operation is indicated by the force of the stream which escapes from the pet-cock when it is open. When the pump is in good condition the water begins to escape promptly in a strong stream as soon as the pump-plunger begins its inward stroke, and continues to escape until the plunger completes its stroke. If the pump is not in good condition, this escaping stream is weak and is apt to continue during the outward stroke of the pump-plunger. It is difficult to tell, however, when the engine is running slowly, whether the pump will work well at higher speeds, and therefore a locomotive runner should always test the condition of the pumps during the previous run.

QUESTION 459. _What should be noticed in connection with the throttle-valve?_

_Answer._ As a failure of the throttle-valve to work may be the cause of a most serious accident, it should be certain that it is in good working condition, that all the bolts, pins and screws and other accessories are in good working order. It should also be known whether the throttle-valve is steam-tight. This can be learned by observing whether steam escapes from the exhaust-pipes or cylinder-cocks when the latter are open, the reverse lever in full gear, and the throttle-valve closed. If the throttle-valve leaks, enough steam may accumulate in the cylinder, when there is no one on the engine, to start it, and in this way cause a serious accident. The throttle-lever should always he fastened with a set-screw or latch of some kind when the engine is standing still.

QUESTION 460. _In inspecting the cylinders, pistons, guides and connecting-rods, to what points should the attention be directed?_

_Answer._ It should be known whether the piston packing is properly set out, that is, whether it is so tight that it will not “_blow through_,” or leak steam from one end of the cylinder to the other, which of course will waste a great deal of steam. Of the two evils, it is, however, better to have piston-packing too loose than too tight, because if it is too tight, it is liable to cut or scratch the cylinders so as to make it necessary to rebore them, and at the same time if the packing-rings are lined with Babbitt metal, the heat created by the intense pressure and friction will melt the metal. In some cases the cylinders become heated to so high a temperature from this cause that the wood-lagging with which they are covered on the outside is burned.

The packing of the piston-rods should be steam-tight, and it should be observed whether the rod and the pump-plunger are securely attached to the cross-head.

The utmost care must be exercised to keep the guides well oiled. The oil cups on the guide-rods or cross-heads, when they are placed on the latter, must be kept clean, so that the oil will flow freely, and yet not too rapidly, on the surfaces exposed to friction. The same thing is true of the oil-cups on the connecting-rods. Attention should be given to the brass bearings of the connecting-rods to see that they are not so loose as to thump, nor keyed so tight on the crank as to be liable to heat. The latter can be easily known by moving the stub-end lengthwise of the journal. They should never be so tight that they cannot be thus moved with the hand. Especial attention should be given to seeing that all the bolts and nuts on the connecting-rods are tight. There are no parts of a locomotive which require more careful attention in order to keep them lubricated, and thus prevent them from heating and being “cut,” than the bearings on the crank-pins and the slides of the cross-head. Examination should be made to see that neither the piston-rods, pump-plungers, guides, connecting-rods nor crank-pins are bent or sprung.

QUESTION 461. _How can it be known whether the piston-packing is too loose or_ “_blows through?_”

_Answer._ It can usually be noticed in the sound of the exhaust, which can be heard very distinctly on the foot-board when the furnace door is opened. If the packing is not tight, it produces a peculiar wheezing sound between and after each discharge of steam. If the packing leaks, it will also be indicated by the escape of steam from _both_ the cylinder-cocks, if they are open, just after the crank passes the dead point. This will usually show in which of the cylinders the packing is too loose. The same thing will occur, however, if either or both of the main valves leak, so that it is often hard to determine whether the “blow” is due to a leak from the valve or from the piston. Of course, it may sometimes happen that both leak, or that the piston on one side and the valve on the other leak, so that often the diagnosis of the disease, as the doctors say, is extremely difficult. Careful observation and experience will, however, aid a locomotive runner in detecting such defects much more than any directions which can be given here.

QUESTION 462. _What is meant by “setting out packing,” and how should it be done?_

_Answer._ “_Setting out packing_” is simply expanding the rings when they get too loose. With ordinary spring packing, figs. 96 and 97, which is now generally used, this is done by screwing up the nuts _b_, _b_, _b_, which, as was explained in answer to Question 169, compresses the springs _a_, _a_, _a_, and thus expands the rings _A_, _A_. In doing this, as already stated, great care must be exercised not to screw the nuts up too hard, and it is always better to have the packing too loose than too tight. Care must also be taken to keep the piston-rod in the centre of the cylinder, otherwise there will be undue pressure and wear on the stuffing-box. After the nuts are screwed up, the position of the piston-head should be tested with a pair of callipers. This is done by placing one leg of the callipers against the side of the cylinder, and setting them so that the other leg will just touch the edge of the projection _E_, fig. 96, or the end of the piston-rod. Then by placing the callipers above and below, and on each side of the piston, it will appear whether it is too high or too low or too near either side; then by loosening the nuts on one side and tightening them on the other it can be moved to a central position. Ordinarily this work is intrusted to persons who are employed for the purpose. A young locomotive runner, fireman or mechanic will, however, always do well to familiarize himself with such duties, and, if possible, do it himself, under the direction of those who are skilled in that kind of work.

QUESTION 463. _If the stuffing-box of the piston-rod leaks, what should be done?_

_Answer._ If the packing in it is in good condition, it can usually be made tight by simply screwing up the gland. In doing this, the nuts on the bolts should not be screwed up more than is necessary to make the packing steam-tight. Any greater pressure only increases the friction on the piston-rod unnecessarily. In doing this, the two bolts must be screwed up equally, otherwise the gland will be “canted,” that is, inclined so as to “bind” or bear unequally and very hard against the piston-rod, and thus be liable to cut or scratch it. After packing has been in the stuffing-box a long time, it becomes very hard and compact, and sometimes partly charred. Then either it must be removed and new packing be put in, or, if in tolerably good condition, it can often be made to work well by simply reversing it, that is, by putting that which was at the bottom of the stuffing-box on top and _vice versa_. Before packing is put into a stuffing-box, the former should always be thoroughly oiled.

QUESTION 464. _When the slides of the cross-heads wear, how is the lost motion taken up?_

_Answer._ When there are gibs on the cross-head, the lost motion can be taken up by putting “_liners_” or “_shims_,” that is, thin pieces of metal, between them and the cross-head, so that they will fill up the space between the guide-bars. When there are no gibs, the guide-bars must be taken down, and the blocks between them at each end must be reduced in thickness so as to bring the bars nearer together. In doing this, great care must be taken that the guides are accurately “in line” with the centre line or axis of the cylinder. This work should never be intrusted to any excepting skilled workmen, from whom those who are inexperienced should seek instruction.

QUESTION 465. _When the brass bearings of the connecting-rods become too loose on their journals, what should be done?_

_Answer._ They must be taken down, and the two surfaces in contact must be filed away so as to bring them closer together. In doing this they must be filed square with the other surfaces, otherwise they will not bear equally on the journals when they are keyed up. Before attaching them permanently to the rods, they should be keyed on the journal in the strap alone, so that it can be known by trial whether they move freely and yet are tight enough to prevent thumping on the journal. When they are attached to the rod, it is very important, especially with coupling or parallel-rods, that the correct length from centre to centre of the bearings be maintained. It is much better to leave coupling-rods loose on their journals, because, if the bearings are keyed up tight, the rods are sure to throw an enormous strain on the crank-pins, as the distance between the centres of the axles is not always absolutely the same, owing to the rise and fall of the axle-boxes in the jaws. It is therefore always best to have a little play in the coupling-rods, and it is safe to say that much more mischief is done by meddling with the coupling-rod brasses than by neglecting them.

QUESTION 466. _What part of the valve gear should receive attention when the engine is inspected?_

_Answer._ All the bolts, nuts and keys should be carefully examined to see that they are properly fastened. The bolts and nuts in the eccentric straps are especially liable to become loose, and as they are between the wheels, and therefore not easy of access, are often neglected. The oil-holes should all be seen to be clear, otherwise it will be impossible to keep the journals well oiled. The eccentric straps and the link blocks are very liable to be imperfectly oiled, and when the former become dry and cut, they throw a great strain on the eccentric-rods, which is liable to break them. When this occurs the strap and the portion of the rod which is attached to it revolve with the eccentric, and frequently a hole is thus knocked into the front of the fire-box, which disables the engine. The valve gear is, with the exception, perhaps, of the pumps and injector, the most delicate part of the locomotive, and more liable to get out of order than any other, and should therefore be watched with the greatest care.

QUESTION 467. _How can it be known whether the main valves of a locomotive are tight?_

_Answer._ As already indicated, the symptoms which manifest themselves when a valve leaks are very similar to those which appear when the piston packing leaks. If the valve is moved to its middle position and steam is admitted into the steam-chest, and it then escapes from both cylinder-cocks, it is apparent that the valve is not tight. But the valve faces of locomotives usually wear concave, because the valves are worked most about half-stroke, so that they will often be tight when in the centre of the face, but will leak at the ends of the full stroke. This will become apparent by the peculiar wheezing sound, already referred to, when the engine is at work. As has been explained, it is, however, often very difficult to determine whether this sound is due to a leak at the pistons or the valves. If the packing of the valve-stem leaks, it can be remedied in the manner described for making that of the piston-rod tight.

QUESTION 468. _To what points of the running gear should attention be directed during inspection?_

_Answer._ All the wheels of the engine and tender should be carefully examined to see that they are sound. A fracture in a driving-wheel is usually apparent if the wheel is carefully examined. The condition of ordinary cast iron tender and truck-wheels is revealed on striking them with a hammer, when if they are sound they will give out a peculiar clear ring; whereas if they are fractured, the sound produced by the blow of the hammer will be dead, like that of a cracked bell. The flanges of the wheels should also receive attention to see that they are not broken, as such a fracture is not always revealed by the sound produced by a blow from a hammer. The axles too should be examined to see that the wheels have not worked loose on the wheel-seat. When this occurs it often becomes apparent by the oil from the axle-boxes working through between the hubs of the wheel and the axle. This can be observed on the outside of the wheels when the bearings are inside, and inside the wheels when the bearing is outside.

The springs should be examined to see that they are in good condition, and the oil-holes in the boxes must be kept clear, so that the oil can reach the bearings. The tender boxes are kept oiled by packing them with cotton or woolen waste saturated with oil. This should be taken out occasionally and renewed and the boxes cleaned. The working of the driving-boxes up and down the jaws will in time wear them so that there will be some lost motion in the jaws. This will be indicated by a thump when the cranks pass the dead point. A similar thump will, however, be produced by lost motion in the boxes of the main connecting-rod, so that it is difficult to determine, without special examination, the cause which produces the concussion. It is therefore best when an engine works with a thump at each revolution for the runner to stand by the side of it where he can touch the connecting-rods and driving-wheels, and then have the fireman open the throttle-valve so as to move the engine slowly. If the lost motion is in the connecting-rods it can be felt by the jar as it passes the dead points. The same is true of lost motion in the jaws, which can be felt by touching the driving-wheels. When the jaws become worn the lost motion can be taken up by moving up one or both of the wedges. When this is done, great care must be taken to keep the centres of the driving-axles the same distance apart on both sides of the engine, and also to keep their centre lines square with the frames. There should always be centre-punch marks placed on the frames or guide-yokes on each side of the engine in front of the main axle, and at equal distances from its centres, so that when the boxes or jaws become worn the position of the axle can be adjusted with a tram from these marks. Of course, if the main axle is square, it is easy to adjust the trailing axle from it with a tram. If the axles are not square with the frames and parallel with each other, the engine will run towards one side or the other of the track, according to the inclination of the axles. It sometimes happens that the bolts which hold up the wedges in the jaws are broken. When this occurs the wedge drops down, and of course the box has so much lost motion that it soon manifests itself in the working of the engine. These bolts, and also those which hold up the clamps on the frames at the bottom of the jaws, should be examined when the engine is inspected, so as to be sure they are in good condition. The bolts and nuts about both the engine and tender trucks should be watched to see that none are lost or work loose. The engine and tender should occasionally be lifted up from the centre plates of the truck, and the latter be lubricated with tallow. It often happens that these become dry, so that they are difficult to turn when the weight rests on them, and therefore they will not adjust themselves easily to the curves of the track.

QUESTION 469. _What other parts of a locomotive should be examined before starting?_

_Answer._ It should be certain that the brakes on the tender are in good working condition, that is, that the bolts, nuts and keys are all secure, the levers, rods and chains properly connected, and the shoes fastened and not too much worn. If either an atmospheric or vacuum brake is used, it should be tested before starting, to see that the pump or ejector is in good working condition. It is also well to apply the brakes to the train before starting, so as to see whether the connections are in good condition and properly connected. It is always best for the locomotive runner to examine the connections of the brake hose through the whole train himself, to be sure that they are properly made.

The inside of the water-tank should also be examined occasionally, to see whether it is clean, and if not it should be thoroughly washed out. The man-hole should always be covered before starting, in order to prevent cinders and coal from falling in, which are liable to obstruct the pump valves. It is hardly necessary to say that it must always be certain before starting that there is enough water in the tank to feed the boiler until the next point is reached at which a supply can be obtained. The sand-box must also be filled, the bell rope in good condition, and if running at night the reflector of the head-light must be polished and the lamp supplied with oil and the wick trimmed so as to burn brilliantly. The locomotive runner must also see that the proper signals are displayed in front of his engine.

QUESTION 470. _What tools, etc., should every locomotive runner on the road carry?_

_Answer._ A coal shovel, coal pick, long-handled hoe[107] and poker, a pair of jacks, either screw or hydraulic, chains, rope and twine to be used in case of accident, a heavy pinch-bar for moving the engine, a small crow-bar, oil-cans with short and long spouts and another smaller one with spring bottom, a steel and a copper hammer, a cold and a cape chisel, a hand-saw, axe and hatchet, one large and one small monkey-wrench and a full assortment of solid wrenches for the bolts and nuts of the engine, cast iron plugs for plugging tubes, with a bar for inserting them, two sheet iron pails or buckets, different colored lanterns and flags, according to the colors used for signals on the line, and a box with a half-dozen torpedoes.

[107] These are of course not needed on wood-burning engines.

QUESTION 471. _What duplicate parts should be carried with the engine?_

_Answer._ Keys, bolts and nuts for connecting-rods, split-keys, wedge bolts, bolts for oil-cellars of driving and truck boxes, driving and truck spring-hangers, wooden blocks for fastening guides in case of accident, blocks for driving-boxes and links, a half-dozen ³⁄₄-in. bolts, from six inches to two feet long, to be used in case of accident, two extra water-gauge glasses, two glass head-light chimneys.

QUESTION 472. _What should be observed in lubricating a locomotive or any other machinery?_

_Answer._ The most important thing to observe is that the oil reaches the surface to be lubricated. It is of much greater importance that the lubricant should reach the right place than that a large quantity should be used. A few drops carefully introduced on a journal will do much more good than a large quantity poured on the part carelessly. For this reason all oil-cups and oil-holes should be kept clean so as to form a free passage for the oil.