ACCIDENTS TO LOCOMOTIVES.
QUESTION 502. _What are the most serious accidents which may happen in
running a locomotive?_
_Answer._ The most serious accidents are:
1. Collision of two trains approaching each other.
2. Collision of a moving with a standing train.
3. Collision of trains at the crossing of two railroads.
4. Running a train into the opening left by an open draw-bridge.
5. Escape of an engine without any one on it.
6. Running off the track.
7. Explosion of the boiler.
8. Bursting or rather collapse of a flue.
9. Blowing out of a bolt, stud or rivet from the boiler.
10. Failure of the feed-pumps, injector or check-valve.
11. Breaking or bursting of a cylinder, cylinder-head, steam-chest, or
steam-pipe.
12. Breaking or getting loose of the piston or cross-head or bending of
the piston-rod.
13. Breaking or bending of a connecting-rod or crank-pin.
14. Breaking of a tire, wheel or axle.
15. Breaking of a spring, spring-hanger or equalizer.
16. Breaking of a frame.
17. Breaking or getting loose of a part of the valve-gear.
18. Failure of the throttle-valve.
19. Breaking of a coupling.
QUESTION 503. _What should be done to prevent a collision when two
trains are approaching each other?_
_Answer._ The obvious thing to do is to stop the trains as soon as
possible. This is done by applying the brakes at once with all their
power, and then reversing the engine, although it is best not to do
the latter until the train is somewhat checked, as there is always
danger of bursting the cylinder or breaking the cylinder-heads, piston
or connections if an engine is reversed suddenly at a high speed. Of
course the higher the speed, the greater is the danger of injury from
this cause, and therefore it is best, if there is time, first to check
the speed of the train before reversing the engine. When the engine
is reversed, the sand-valves should be opened so as to increase the
adhesion of the wheels, so that when their motion is reversed they may
check the speed of the train as soon as possible. On perceiving danger
ahead the order of procedure should be as follows:
1. Shut the throttle-valve.
2. If the train is equipped with hand brakes alone, blow the danger
signal for their application, or if the train has a continuous brake,
apply it with its full force.
3. Reverse the engine and open the throttle and the sand valves.
4. If a collision is inevitable, shut the throttle-valve before the
engines meet, because if it is left open, after the collision and when
the speed of the train is checked, the engine, if not disabled, will by
its own power crush through the wreck and thus do additional damage.
QUESTION 504. _What should be done if a standing train should see
another train approach it and there should be danger of a collision?_
_Answer._ The locomotive runner of the standing train should start his
engine in the same direction as the approaching train is running, as
quickly as possible, because the shock of the collision will be very
much lessened if both trains are moving in the same direction compared
with what it would be if one was standing still.
QUESTION 505. _What should be done to avoid a collision at a railroad
crossing?_
_Answer._ As was explained in answer to Question 485, trains should
always come to a dead stop before crossing another railroad on the same
level. If, however, through any means danger of such a collision should
be incurred, then evidently the one train should be stopped and the
other moved out of the way as soon as possible.
QUESTION 506. _How can an accident by running into the opening at a
draw-bridge be avoided?_
_Answer._ First by ALWAYS coming to a dead stop before reaching it,
and second by not starting again until it is absolutely certain that
the draw is closed. Of course if a locomotive runner of an approaching
train finds a draw open, the only thing he can do is to stop as soon as
possible.
QUESTION 507. _What measures should be taken to prevent locomotives
from escaping without a responsible person on them?_
_Answer._ In the first place when a locomotive is left standing
the throttle-valve should always be _closed_ and _fastened_, the
cylinder cocks should also be opened so that if any steam leaks into
the cylinders it will not accumulate there, but will escape, and the
reverse lever should be placed in the centre of the sector, so that if
by any accident the throttle should be opened the engine will not start.
QUESTION 508. _If a locomotive should escape, what should be done, and
how may it be captured?_
_Answer._ The first thing to be done is to telegraph to the stations
towards which the escaped engine is running, either to keep the track
clear, or, if there is a train approaching, to open a switch and thus
let the engine run off the track. An escaped engine may be captured by
a swifter engine following it, but this is always attended with great
danger, as the first engine may leave the track or become wrecked. A
safer plan is to telegraph ahead of the escaped engine and have an
engine placed in a position where the track can be seen for a long
distance in the direction in which the runaway is expected. As soon
as the latter comes in sight, the waiting engine should start in the
same direction, so that when they get near to each other they will
both be running in the same direction and at nearly the same speed.
By regulating the speed of the front engine, the following one may be
allowed to come up to it quite gently, and then a man can easily climb
from the one engine to the other, and thus both be stopped.
QUESTION 509. _What should be done in case an engine gets off the
track?_
_Answer._ The first thing to do is to close the throttle-valve and
“signal for brakes,”[114] or apply the continuous brakes if the train
is equipped with them, and then reverse the engine. If its position
after it stops is much inclined, it is generally necessary to draw the
fire to prevent injury to the heating-surface, a part of which is then
usually exposed to the steam, and therefore not covered with water.
[114] This expression means, among railroad men, to signal to
brakemen by blowing the whistle to have them apply the brakes.
QUESTION 510. _How is a locomotive replaced on the track in case it
gets off?_
_Answer._ It is impossible to give any directions for replacing
locomotives on the track which will meet the great variety of
circumstances which occur in practice. If the engine has not run far
from the rails, it can usually be run on again by placing blocks
of wood under the wheels and thus running them up to their proper
position, but if the engine falls on its side or runs down an
embankment, it is usually necessary to send for the appliances which
are now provided on nearly all roads for removing wrecks and replacing
engines on the track. These appliances are generally stored in what is
called a wrecking or tool car, which is placed at a convenient point
on the road, from which it can be sent to any place where its services
are likely to be needed. Such cars are generally provided with ropes,
jack-screws, chains, crowbars, levers, etc., to be used in such cases,
and generally a special set of men is sent with the wrecking car to
direct and assist in replacing engines and cars on the track. It would
lead us too far to describe all the methods of doing this employed
under various circumstances; and as such work seldom forms part of the
duties of a locomotive runner, a complete description would be out of
place here.
QUESTION 511. _After an accident which disables the engine, what is the
first thing to do?_
_Answer._ The first thing to do is always to “_protect the train_;”
that is, to send out signal men in each direction to stop approaching
trains; otherwise they might run into the wrecked train, and thus cause
a double accident.
QUESTION 512. _What is the chief cause of boiler explosions?_
_Answer._ The cause of all boiler explosions, as happily expressed by
a prominent American engineer,[115] is THAT THE PRESSURE INSIDE THE
BOILER IS GREATER THAN THE STRENGTH OF THE MATERIAL OUTSIDE TO RESIST
THAT PRESSURE. This may occur in two ways: first, and most frequently
with locomotives, from insufficient strength of the boiler to bear
the ordinary working pressure; and second, from the gradual increase
of heat and pressure until the latter is greater than the boiler was
calculated to bear.
[115] See Fifth Annual Report of the American Master Mechanics’
Association, page 196.
Insufficient strength may be due: 1, to defects of the original design,
owing to the ignorance of the strains to which the material of the
boiler will be exposed, and its power of resistance; 2, to defective
workmanship and material, which can usually be discovered by careful
inspection; 3, to the reduction of the original strength of the boiler
by ordinary wear and tear or neglect, which can also usually be
discovered by careful inspection.
The first two causes have been fully discussed in the part relating
to boiler construction, and the last under the head of inspection of
locomotives.
Over-pressure is nearly always due to some defect of the safety-valve,
or to the fact that it is overloaded. This latter often occurs when
safety-valves are set by a defective steam gauge, which indicates too
little pressure. Over-pressure may also occur by letting an engine
stand alone with a large fire in its fire-box and possibly with the
blower turned on.
A boiler may, by suddenly opening the throttle-valve, undoubtedly be
subjected to very severe strain that may possibly be sufficient to
cause its destruction, even though it had sufficient strength to bear
the ordinary pressure at which the safety-valve blows off. Suddenly
opening or closing the throttle-valve may produce a violent rush
of steam and water against the part of the boiler whence the steam
is drawn. The percussion of the water and steam in such cases has
been known to shake the whole boiler, and to lift the safety-valve
momentarily right off its seat.[116] The weakest parts of a locomotive
are the two sides where the barrel joins the outside fire-box. Many
boilers, especially those with a high wagon-top, have flat spaces at
this point, which it is impossible to stay properly. It is at this
point, too, that the expansion and contraction of the tubes and the
outside shell exert their greatest strains, and it will therefore be
found, generally, that the seams at this point begin to leak before
any others, and for these reasons it is believed that all the seams
which join the outside shell of the fire-box to the barrel should be
double-riveted.
[116] Wilson on Boiler Construction.
The practice of ascribing steam-boiler explosions to obscure causes has
been productive of much mischief, as it engenders a carelessness on
the part of those having charge of them, who have been led to believe
that no amount of care will avail against the mysterious agents at
work within the boiler. Explosions are also, in the absence of other
convenient reasons, very generally attributed to shortness of water.
This is often nothing more than a convenient method of shifting the
responsibility from the builder or owner of the locomotive to the
runner or fireman, who, if not killed by the explosion, in many cases
might just as well be, so far as his ability to defend himself is
concerned.[117]
[117] Wilson on Boiler Construction.
QUESTION 513. _What should a locomotive runner and fireman do to avoid
and prevent explosions?_
_Answer._ 1. The height of the water in the boiler should always be
maintained so as to cover the heating surfaces. 2. The boiler should be
kept as clean, that is, as free from scale, mud and other impurities,
as possible. 3. It should never be subjected to strains from sudden
heating or cooling. 4. The steam-gauge and safety-valves should be
examined and tested frequently, to be sure they are in order; and 5,
they should examine every part of the boiler which is accessible, but
especially the stay-bolts, to see that there is no fracture of any part
or any injurious corrosion or other dangerous defect.
QUESTION 514. _What should be done in case of the bursting or collapse
of a tube?_
_Answer._ As soon as possible after it occurs, the runner must stop the
train, and close first the end of the flue in the fire-box, and then
that in the smoke-box, by driving in _iron plugs_, which are usually
provided for the purpose. These plugs are attached to the end of a bar,
with which they are inserted into the tubes. If the escape of water
and steam from the tube is so great as to make it difficult to see the
end of the tube, the steam may sometimes be drawn up the chimney by
starting the blower. If, however, the escape is so great as to make it
impossible to insert the plug, then the steam pressure must be reduced
by running with both pumps on, or by starting the injector; or it may
be necessary to draw the fire and cool off the engine. When a flue
collapses, the front end of which is behind the steam or petticoat
pipes, it is usually necessary to cool off the engine before a plug
can be inserted, especially if any considerable amount of water and
steam escape from it. While driving in the plug, the runner and fireman
should always keep themselves in such positions that the plug can not
hit them in case it is blown out by the steam. If the engine is not
supplied with iron flue-plugs, a wooden plug can be cut of the proper
size and driven in. This can be attached to the bar referred to and
inserted; but if no such bar is carried with the engine, the wooden
plug can be made on the end of a long pole and then cut nearly off. It
is then inserted into the flue and driven in and broken off. It will be
found that such plugs will burn off even with the end of the flue, but
will not burn entirely out.
QUESTION 515. _What should be done in case a bolt, stud or rivet blows
out of the boiler and thus allows the steam or hot water to escape?_
_Answer._ If it is accessible, cut a plug on the end of a long pole and
drive it in in the same way as described above. This will avoid the
necessity of cooling off the engine; but in some cases it will be found
that a plug can not be inserted or driven in without drawing the fire
and cooling off the boiler.
QUESTION 516. _In case it is found necessary to draw the fire and cool
off the boiler, and if so much water has escaped as to uncover the
crown plate, what must be done?_
_Answer._ If the leak has been stopped or the fault remedied, one of
the safety-valves should be taken off and water poured into the boiler
with pails or buckets through the opening left by the removal of the
safety-valve until the crown sheet is covered. The fire may then be
kindled again and the engine complete its journey. When bituminous
coal is used for fuel, the necessity for drawing the fire in case of
accident may often be avoided by completely covering or “banking” the
fire with fine coal which has been wet, and closing the dampers and
opening the furnace door. In this way the fire may be smothered and the
boiler cooled without putting the fire out, so that after the defect is
remedied it will not be necessary to rekindle it.
QUESTION 517. _What must be done in case of the failure of one or both
of the feed pumps or of the injector or check-valve?_
_Answer._ If one of the pumps fails the other one may be used, but
the defect or obstruction to the first should be remedied as soon as
possible, because the second may also fail. It will then be necessary
to depend upon the injector alone, if there is one, for feeding the
boiler. Only after all the appliances for feeding the boiler have
failed and the water is so low as to be in danger of exposing the crown
sheet, should the fire be drawn or banked, and the runner should then
at once give the proper signals for warning and the protection of his
train, and if he is unable to repair the pumps or injector, he must
send for aid to the nearest accessible point.
QUESTION 518. _In case a pump fails, how should it be examined in order
to discover the defect?_
_Answer._ As explained in the answer to Question 458, the working
of a pump is usually indicated by the stream which escapes from the
pet-cock. If, when this is opened, steam and water escape, it is an
indication that the check-valve is not working properly. When this
occurs hot water will escape if the pet-cock is opened when the engine
is standing still, but the pump may still feed the boiler if the upper
or pressure-valve works properly. When the check-valve does not work as
it should, it is also indicated by the heating of the feed-pipe, owing
to the escape of hot water from the boiler through the check-valve
when the pet-cock is opened. If, when the plunger is drawn out of the
pump, air is sucked in through the open pet-cock, then the upper or
pressure-valve of the pump does not work, but the working of the pump
may still be secured by the working of the check-valve; but if the
pump, air-chamber and feed-pipe then get filled with air, the plunger
may compress this air at each stroke, and as it can then follow the
plunger during its outward stroke, the latter will not suck water, but
will simply compress the air during the inward stroke, which will then
expand during the outward stroke. This will be indicated by the escape
of air from the pet-cock when the plunger is moving inward, and the
suction of air when the plunger is moving outward. This can be known by
holding the hand in front of the pet-cock. Usually, however, the air is
mixed with water so that the stream which escapes from the pet-cock is
broken or irregular. If air escapes from the pet-cock during the inward
stroke of the plunger, but none is sucked in during the outward stroke,
it shows that there is a leak somewhere in the pump or pipes, and that
it is pumping air instead of water. The leak may be in the stuffing-box
of the plunger, the joints of the pump or pipes, in the hose or their
connections with the supply-pipe or tender. If neither air nor water
escapes from the pet-cock during the inward stroke of the pump plunger,
or, if the stream of water at that time is weak, then it indicates that
the suction or lower valve of the pump is not working properly. The
same thing will occur if the pipe, pump or tender-valve is obstructed.
If there is a cock, as there always should be, just above the
suction-valve, it will aid us very much to discover the fault when the
pump will not work. If, when this cock is opened, cold water escapes
from it, the fault is in the suction-valve; if hot water, then it is
the pressure and check-valves which are leaky, obstructed or broken,
and consequently the hot water from the boiler leaks back into the
pump. In the absence of such a cock, the fault can often be discovered
by feeling the pump barrel with the hand. If the pump can not be made
to work, and the fault is found to be in the lower valve, it must be
taken out and examined; or if the fault is in the pipes, it can usually
be easily remedied. If the pipes are burst with only a small fracture,
it can usually be remedied by covering the aperture with canvas or
rubber and wrapping twine around it tightly. The upper valve of a pump
must, however, never be taken down without first being sure that the
check-valve is tight, because if it is not, the person will be likely
to be scalded in taking the pump apart.
Directions for managing an injector, and also for taking care of pumps
in cold weather, have already been given in the answers to Questions
142 and 488.
QUESTION 519. _What should be done in case of the breaking or bursting
of a cylinder or cylinder-head?_
_Answer._ The main connecting rod must be taken down on that side of
the engine. The piston should then be moved to the front or back end of
the cylinder and wooden blocks be placed between the guides so as to
fill up the space between the cross-head and the end of the guide-bars,
and thus prevent the cross-head and piston from moving. The valve stem
should then be disconnected from the rocker, and the valve moved to the
middle of the valve face, so as to cover up both steam-ports. It must
then be fastened in that position by screwing up _one_ of the bolts
of the stuffing-box of the valve stem, so as to make the gland bind
against the valve stem. The train should then be run cautiously to the
next station with the use of _one_ cylinder. If the engine is not able
to haul the train with one cylinder, then it should be uncoupled from
the train and run to the first telegraph station or other point where
the aid of a helping engine can be obtained or telegraphed for. In the
meanwhile the train must be protected by the proper signals. Should
the engine continue its journey with one cylinder, it must be started,
if it should happen to be standing at the dead point, by _pushing_ or
by means of _crow-bars_. In so doing, however, the bars should not be
put between the spokes of the wheels, as they may easily be caught in
the wheels when the engine starts, and in this way the spokes be broken
or the persons who are using the crow-bars be badly hurt.
QUESTION 520. _What must be done in case a steam-chest or steam-pipe is
broken?_
_Answer._ If a steam-chest is broken a block of wood should be bolted
over the mouth of the steam passage, so as to prevent the escape of
the steam from the steam-pipe on that side. It will sometimes require
considerable ingenuity to devise means of fastening such a block or
blocks of wood so as to cover the mouth of the steam passage. As
cylinders are now usually made, the blocks can be fastened by cutting
them to the proper form and size, and then placing a thick block on
top, and bolting the steam-chest cover down on top of it. If the cover
is broken, a part of it may be used or a piece of plank with a few
holes bored into it be employed instead. In some cases a piece of
board can be bolted over the end of the steam-pipe. When the latter is
broken, it should be taken down and a piece of board or plank bolted
over the opening of the ~⊤~-pipe to which the steam-pipe was attached.
The engine can then be run with one cylinder as before, although
usually in such cases it is not necessary to disconnect any other parts
than the valve stem.
QUESTION 521. _What must be done if a piston, cross-head,
connecting-rod or crank-pin is broken or bent?_
_Answer._ If the piston, cross-head or main connecting-rod is broken,
the same course must be pursued as when a cylinder is broken. If a
coupling-rod or a crank-pin of a trailing-wheel is broken, then it is
necessary to take down both the coupling-rods, but not to disconnect
the main connecting-rods or their attachments, unless they are injured.
QUESTION 522. _If one coupling-rod is broken or taken down, why must
the other be taken down also?_
_Answer._ Because if only one rod is used there is then nothing to help
the cranks of the trailing wheels past the dead-points, so that in
starting, or if they are moving slowly when they reach these points,
they are quite as likely to revolve in one direction as the other.
If they happen to turn in the reverse direction to that in which the
wheels to which they are coupled are moving, then the crank-pins of one
or the other pair of wheels are very liable to be broken or bent.
QUESTION 523. _What must be done if a driving-wheel tire or
driving-axle breaks?_
_Answer._ If a tire on a main driving-wheel or the wheel itself
breaks, the driving-box of the broken wheel or tire should be held up
by putting a wooden block under the box. An ordinary American engine
can then be run on three driving-wheels, but it must be run with the
utmost caution. If the engine has more than four driving-wheels there
is usually less difficulty in running it, if one of the main wheels
is injured, than if there are only four. But it is almost impossible
to give directions which will be applicable to all the accidents of
this kind that may occur to different kinds of engines. If none of the
connecting-rods, crank-pins or crank-pin bosses are injured, it is not
necessary to disconnect either side, but if the injury is of such a
nature that the coupling-rod must be taken down on one side, the one
on the other side must be taken down too. If the main crank-pin and
connecting-rod are not disabled, both cylinders may be used even if
one of the main wheels or tires is broken. But even if one side of the
engine must be entirely disconnected, the engine may still be run with
one cylinder and by driving one wheel. If a main axle breaks the engine
can usually be run, but great caution must be exercised. In such cases,
however, if assistance or a telegraph office is near where the accident
occurs, it is usually best to send for assistance at once, rather than
take the risks which attend the attempt to run an engine so seriously
injured.
QUESTION 524. _What must be done when a trailing or leading
driving-wheel, tire or axle breaks?_
_Answer._ Very much the same course must be pursued as was described
in the previous answer, although it is generally less difficult to run
with a trailing or leading axle broken than it is when the main axle
has met with such an accident.
QUESTION 525. _What must be done if an engine-truck wheel or axle
breaks?_
_Answer._ It is usually best to chain up the end of the truck-frame
over the broken axle or wheel to the engine frame and place a cross-tie
across the other end of the truck-frame, between it and the engine
frame, so that the weight of the engine may rest on the cross-tie.
If a part of the flange or a piece of the wheel is broken out, the
wheels should be turned around so that the unbroken part will rest on
the rail, and they should then be chained or otherwise fastened so
that they cannot revolve, and thus be made to slide on the rails and
carry the weight of the engine in that way. The same plan is employed
if a tender wheel breaks, but one end of a tender-truck frame must be
chained up. It is usually necessary to place a cross-tie across the top
of the tender, and fasten the chains to it.
QUESTION 526. _What must be done in case a driving-spring,
spring-hanger or equalizing-lever breaks?_
_Answer._ As the breaking of a spring or spring-hanger may cause a
more serious accident, the engine and train should be stopped as soon
as possible after it occurs. If the hanger is broken and there is a
duplicate on hand, it should be substituted in place of the broken
one. If there is no duplicate, then the spring should be taken down,
and a wooden block be placed between the top of the driving-box and
the frame to support the weight which before rested on the spring. In
order to insert this block, if it is a front spring which is broken, it
is usually best to raise the engine with jack-screws or run the back
wheels on inclined blocks of wood placed under each of the back wheels.
This raises the weight off from the front-wheels, and the block can
then be inserted between the box and frame. If it is one of the springs
over the back wheels which is broken, the front wheels should be run on
the wooden wedges. Such wedges can soon be cut out of a cross-tie with
an axe, or by sawing a square stick of wood diagonally it will make
two such wedges. The end of the equalizing lever next to the broken
spring must be supported by inserting a piece of wood under it. This
will usually be held securely by the weight which is suspended from the
opposite end, bearing the blocked end down on the block.
QUESTION 527. _What should be done if an engine-truck or tender spring
breaks?_
_Answer._ Very much the same course must be pursued that is employed
when a driving-spring breaks, excepting that usually the weight can be
lifted off from a truck-box easier by placing a jack under the end of
the truck-frame than by the method described. Usually, too, each of the
truck-springs supports the weight on two of the wheels, so that the two
boxes must be blocked up.
QUESTION 528. _What must be done in case the engine-frame is broken?_
_Answer._ Usually very little need be done excepting to exercise more
than usual caution in running, and to reduce the speed. Of course the
breakage of a frame may disable the engine, but ordinarily in such
accidents that is not the case.
QUESTION 529. _How can it be known if an eccentric has slipped on the
axle?_
_Answer._ It is indicated at once by the irregular sound of the
exhaust, or, as locomotive runners say, the engine will be “_lame_.”
QUESTION 530. _When it is known that an eccentric has slipped, how can
it be learned which is the one that is misplaced?_
_Answer._ This can usually be learned by examining the marks which
should always be made on the eccentrics and on the axles. If no such
marks have been made by the builder of the engine, the runner himself
should make them, after the valves have been set correctly. The effect
upon the valve when an eccentric slips is either to increase or
diminish the lead. Therefore, by running the engine slowly with the
link first in full forward and then in full back gear, and observing
whether steam is admitted at each end of the cylinder just before the
crank reaches the dead points, it can be known which eccentric has
moved. If it has slipped in one direction the lead will be increased
and steam will be admitted to the cylinder some time before the piston
reaches the end of the stroke. If it has moved the opposite way, the
lead will be diminished and steam will not be admitted until after the
piston has reached the end of its stroke. The admission of steam will
be indicated by its escape from the cylinder cocks.
QUESTION 531. _If by any means the valve stem or either of the
eccentric rods should be lengthened or shortened, how can it be known?_
_Answer._ The crank on one side should be placed at one of the dead
points and the cylinder-cocks opened; then admit a little steam to the
cylinder, by opening the throttle-valve slightly, and throw the reverse
lever from full gear forward to full gear backward, and observe whether
steam escapes all the time from the end of the cylinder at which the
piston stands. Then repeat the operation with the crank at the other
dead point. If either of the eccentric rods or the valve stem have
been lengthened or shortened, it will cause the valve to cover the
steam-port either at the front or back end of the cylinder, so that
no steam will escape from the cock at that end. If the length of one
of the eccentric rods has been changed, then when the altered rod is
in gear the valve will have too little or no lead at one end of the
cylinder and too much at the other. If, therefore, this occurs when the
forward rod is in gear and _not_ in back gear, it indicates that the
length of the forward rod has been altered. If the reverse occurs it
shows that it is the back-motion rod whose length has been changed. It
must be observed that if the length of an eccentric rod is altered the
lead will be changed only at that part of the link which is operated
by the altered rod. That is, if the forward eccentric rod is too long
or too short, the lead at the front and back ends of the cylinder
in forward gear only will be affected. If the back eccentric rod is
changed the valve will be affected only in back gear. If, however, the
length of the valve stem is changed, the lead will be changed in both
forward and back gear. The valves on each side of the engine can, of
course, be tested in the same way.
QUESTION 532. _When it is discovered which eccentric has slipped, how
should it be reset?_
_Answer._ If it has been marked, it is simply turned back so that the
marks correspond with each other again. This is done by first loosening
the set-screws, and, after the eccentric is turned to the proper place,
tightening them up again. When an eccentric slips it is often caused
by the cutting of the eccentric-straps, valve or other part of the
valve-gear, so that these should always be examined to see whether
they are properly oiled. If the eccentrics have not been marked, the
valve may be set by placing the crank at the forward dead-point, and
the reverse lever in the front notch of the sector and the full part
of the forward-motion eccentric _above_ the axle. Then admit a little
steam into the steam-chest, open the cylinder cocks, and move the
forward-motion eccentric slowly forward until steam escapes from the
front cylinder cock, which will show that the steam-port is opened and
the valve has some lead. To set the backward-motion eccentric the crank
is placed in the same position, but the reverse lever is thrown into
the back notch and the full part of the eccentric is placed _below_ the
axle. Then move this eccentric forward until steam escapes from the
_front_ cylinder cock as before. In order to verify the position of
the eccentrics the crank may be placed at the back dead-point and the
reverse lever moved backward and forward, at the same time observing
whether steam escapes from the back cylinder cock when the link is in
back and forward gear.
QUESTION 533. _What should be done in case an eccentric-strap or rod,
or rocker arm or shaft, or the valve stem breaks?_
_Answer._ If an eccentric-strap or rod breaks, the broken rod and strap
should be taken down, and the valve-stem disconnected from the rocker
and the valve fastened in the middle position of the valve face, and
the engine should be run with one cylinder only. The same course must
usually be pursued if a rocker breaks. If the valve-stem breaks, it is
not necessary to disconnect the link and eccentric rods, but simply to
fasten the valve in the centre of the valve face.
QUESTION 534. _If a link hanger or saddle, or a lifting arm should
break, what may be done?_
Answer. The valve-gear may be used on that side of the engine by
putting a wooden block in the link slot above the link block, so as
to support the link near the position at which it works the valve
full stroke forward. Of course the engine can then be run in only one
direction, and should therefore be run with the utmost caution. If,
however, it should be necessary to back the train on a side track, it
can be done by taking out the wooden block and substituting a longer
one, so that the link will be supported in a position near that at
which it works the valve full stroke backward. These blocks must be
fastened in some way, either with rope or twine, so that they will be
held in their position when the engine is at work.
QUESTION 535. _If the lifting shaft itself or its vertical arm, the
reverse lever or rod, should break, what can be done?_
_Answer._ If it is impossible to devise any temporary substitute or
method of mending them, both links can be blocked up as described above.
QUESTION 536. _In case the throttle-valve should fail, what should be
done?_
_Answer._ If such an accident occurs, especially if it happens about a
station, it is attended with great danger. If it is found that steam
can not be shut off from the cylinders with the throttle-valve, then
the reverse lever should be placed in the middle of the sector. If
this does not prevent the engine from moving, the reverse lever should
be alternately thrown into forward and then into back gear, and at
the same time every aperture, such as the safety-valve and heater
cocks, should be opened, and every means be taken to cool the boiler
as quickly as possible. The fireman should open the furnace door,
close the ash-pan dampers, and start the blower so as to draw a strong
current of cold air into the furnace and through the tubes. At the same
time the injector should be started and the fire drawn as quickly as
possible. After the boiler is cooled, the cover of the steam-dome may
be removed and the valve examined if the defect can not be discovered
in any other way. Of course if the accident occurs on the open road,
the train must be at once protected by sending out signals in each
direction.
QUESTION 537. _What must be done in case a coupling breaks?_
_Answer._ When a coupling between the cars or tender breaks, if the
front end of the train is immediately stopped, there will be danger
that the back end of it, which is broken loose, will run into the front
end, and thus do great damage. As it always occurs, when a coupling
of a passenger train breaks, that the signal bell in the cab is rung,
the first impulse of a runner under such circumstances is to stop the
engine. He should, however, be careful not to do so if on shutting off
steam he finds that the train has broken in two, but should at once
open the throttle in order to get the front end of the train out of
the way of the rear end. The ease with which the speed of a train is
arrested with continuous brakes has increased the danger of accident
from this cause. Usually a runner learns by the sudden start of the
engine that the train has separated, and when that occurs he should
never apply the brakes.
QUESTION 538. _If from any cause the supply of water in the tender
becomes exhausted, what must be done?_
_Answer._ It is best, if it can be done without risk of injury to the
engine, to run the train on a side track and then draw the fire. If no
water can be obtained near enough to supply the tender with buckets,
help must be sent for; but if there is a well, stream or pond of water
near, the tender can be partly filled by carrying water.
QUESTION 539. _In case an engine becomes blockaded in a snow storm with
plenty of fuel, but runs out of water, what can be done?_
_Answer._ Snow should be shoveled into the tender and steam admitted
through the heater cocks so as to melt the snow.
QUESTION 540. _If a locomotive without an injector should be obstructed
in a snow storm or in any other way so that it could not move, and
therefore could not work the pumps, what should be done in case the
water in the boiler should get low?_
_Answer._ The weight of the engine should be lifted off from the
main driving-wheels and the coupling rods disconnected from the main
crank-pin, so that the main wheels can turn without moving the engine.
These can then be run and the pumps thus be worked. The weight can
usually be most conveniently taken off from the main wheels by running
the trailing wheels on wooden blocks, and thus raising up the back end
of the engine.
QUESTION 541. _If it is impossible, in a snow storm or in very cold
weather, to keep steam in the boiler without danger, what should be
done?_
_Answer._ Draw the fire, blow all the water out of the boiler, empty
the tanks, disconnect the hose and slacken up the joints in the pumps
and injector so that all the water in them can escape, and thus prevent
them from freezing up.