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.