In the management of a Locomotive Engine, many unforeseen circumstances
may occur, requiring the use of that discretion which experience alone
can confer, and which it would be almost impossible to comprise in the
particular instructions contained in the following pages, which, however,
the writer believes to contain all the leading principles of
Engine-driving.
On receiving the signal to start, the Engine-man should only slightly
open the regulator, and let the train run for several yards, before he
opens it, by slow degrees, to the full extent. The object of thus giving
a slight aperture to the regulator in starting, is to avoid any jerk to
the carriages, by which passengers might be annoyed, or even the
coupling-irons broken; to prevent the slipping of the driving-wheels,
from their adhesion being unequal to the inertia of the train, when the
full power of the Engine is suddenly used; and because fully opening the
regulator at starting generally causes the Engine to _prime_
considerably, from the quantity of water condensed in the cylinders and
steam-passages while the Engine was standing. When _priming_ occurs at
starting, the discharge-cocks of the cylinders should be opened to remove
the water. On leaving the station, and frequently on the road, the
Engine-man should watch the train behind him, to see that it is all right
and its motion regular.
The Engine-man should now be standing on the foot-board of the Engine,
which he ought never to leave, unless the machinery is out of order, when
he may leave the Stoker in his place; he should as much as possible be in
such a position as to command, without moving from his place, the
reversing-lever, the whistle, and the regulator, these being the parts
which he is most frequently obliged to use at the shortest notice; his
hand should be upon the regulator, which, when he has arrived at a good
speed, he will gradually ease off, so as to economise steam without
retarding the train: his eye should be constantly directed to the rails
in front of him, that he may be immediately aware of any obstruction, and
at the same time his full attention must be given to the maintaining a
sufficiency of steam at an equable pressure; this is to be done by using
the requisite care in the manner and time of supplying _water_ and
_fuel_.
Water is supplied by opening the cocks in the feed-pipes, which allow the
pumps to act; and the height of water in the boiler is commonly shown by
a glass gauge-tube, and by three gauge-cocks at the side, which should be
opened from time to time, (especially when stopping,) as they afford a
more correct indication of the quantity of water and steam than the
gauge-tube.
One pump, if constantly at work, would, in most Engines, supply as much,
or rather more water than is required by the Engine as equivalent to the
steam consumed; so that by turning on or off either or both pumps, the
Engine-man has the power of regulating the height of the water in the
boiler at discretion.
It may be laid down as an invariable rule, that water alone should always
blow off from the bottom cock (which is from 1 inch to 1.5 inch above the
top of the fire-box), in order that there may be enough water over the
fire-box and tubes to prevent their burning; and few Engines will carry
their water much above the top cock without _priming_, so that the height
of the water may be made to range between these two points, according as
more or less steam is required.
The water is higher when the Engine is running than when stopping: a good
working height for it in most Engines is when _water_ blows off from the
middle cock while running, and _water and steam_ when stopping: an
Engine-man is sometimes obliged to run the water rather lower, if he has
heavy work; but it is always better to keep the level of the water as
high as possible.
It is observed that when any variation takes place in the pressure of the
steam, a corresponding change occurs in the level of the water,--that
when the pressure of the steam rises or falls, the height of the water
rises or falls simultaneously. Partly for this reason, and partly to
allow the more rapid generation of steam, the feed-pumps are not
generally allowed to act when the Engine starts: a knowledge of this fact
also shows the necessity of the water being above the ordinary level,
before a decrease is allowed in the pressure of the steam.
When the Engine is highest on an inclined plane, rather a greater height
of water must be kept over the fire-box than on a level, in order that
the chimney ends of the tubes may be well covered.
The most favourable time for allowing the feed-pumps to act, is when the
steam is blowing off with force from the safety-valve, and the fire
strong; and the least favourable time is when the steam and fire are low:
indeed the Engine-man should manage that it may never be necessary in the
latter case, as the addition of water rapidly lowers the steam.
In order to know the force of the steam, one hand may occasionally lift
or depress for a moment the lever of the safety-valve, according as the
steam is under or over the working pressure; and a little practice will
soon enable a person to judge the extent of excess or deficiency.
Both feed-pumps should not commence working at the same time.
The water should never be allowed to run low before arriving at any part
of the road where considerable power is required, as steam is produced
more rapidly when both pumps are turned off,--a measure which is
imprudent unless the water is high.
When "the feed" is turned on, the Engine-man should try the pet-cock to
see whether the pump is acting freely: the water thrown from it should be
in forcible intermittent jets; warm water with a little steam will
frequently escape from it at first; if this should continue, it may be
concluded that the upper clack does not act; and if the water is in a
continuous stream without pulsations, the lower clack is out of order.
In either case it will not be prudent to trust too much to the faulty
pump, but the evil may frequently be remedied by working the pump a short
time with the pet-cock open, or alternately turned on and off.
Coke is put on the fire by the Stoker, at the order of the Engine-man,
who should hold the chain of the fire-door in his hand, and open it for
as short a time as possible, while the Stoker throws on each shovelful of
coke: the shovel should be well filled, and the coke distributed equally
over the fire.
In most Engines, the fuel need not be higher than the bottom of the
fire-door; and if allowed to fall more than 6 or 8 inches below it, it
must not be expected that the pressure of the steam will be maintained,
if the Engine has a load.
The supply of fuel should be regular, and so arranged that the fire may
have burned up well by the time the steam is most required. As the
addition of fuel causes a temporary reduction of the force of the fire,
coke should not be laid on immediately before arriving at an inclined
plane or any part of the road where much power is required; but when
ascending an incline, coke should be gradually added when the Engine
begins to _beat heavily_,--the draught is then powerful, and a regular
supply of fuel required to keep up the fire.
In other circumstances, provided the fire is low enough to require fuel,
the best time to put on coke is when the water is sufficiently high to
turn off the feed-pumps, the steam slightly blowing off, and the Engine
travelling at a good speed.
No definite instructions can be given for the frequency with which coke
must be laid on the fire, as it varies according to the duty to be done,
and the water consequently to be evaporated: in cases of heavy duty and
bad gradients, it may at times be necessary even at as short an interval
as 2 miles; under contrary circumstances an Engine may sometimes run as
much as 15 miles without adding fresh coke.
The fire should be allowed to run rather low before arriving at the top
of an inclined plane down which the steam will not be used: on beginning
to descend the plane, fuel should be put on the fire, which will burn up
by the time the train reaches the bottom of the plane.
If it is wished to keep up the steam, it is better not to supply water
and fuel at the same time.
While running, the Stoker should occasionally pick the ashes from the
tubes to clear the draught.
By observing the above rules for the supply of water and coke, an
efficient pressure and quantity of steam will be produced, which it must
be the study of the Engine-man to economise. With this view the
regulator should never be kept too far open;--as soon as the train has
acquired the velocity wished, the aperture may be considerably reduced
without diminishing the speed. As any diminution in the amount of steam
used causes a corresponding diminution in the quantity of coke consumed,
the skill of the Engine-man should be unceasingly directed to the
reduction of so heavy an item of Railway expenditure.
If there should be, at any time, an unnecessary quantity and force of
steam, it is readily reduced by opening the fire-door, and by turning on
the feed-pumps; if there should be too little, the Engine-man must be
content to run slowly for a short time, keep the regulator only partially
open, and put on a gradual supply of coke.
When the water in the boiler is high, many Engines begin to prime,
especially after running for several days. When this occurs, the
aperture of the regulator should be diminished, and the fire-door and the
discharge cocks of the cylinders opened: if the height of the water will
allow it, the blow-off cock of the boiler may be opened for a short time
to carry off the sediment, which will be found advantageous.
The Engine-man should frequently look to the working gear, to see that it
is in proper order, and to rectify any deficiency at the next Station.
On nearing a Station where it is intended to stop, the regulator should
be gradually eased off at about five-eighths of a mile from the Station,
so that the train may be more under control, and when from a quarter to
half a mile distant, according to the velocity and weight of the train,
the steam should be completely shut off, and the train brought to rest by
the breaks. In approaching terminal Stations the steam should be shut
off at a greater distance than at the intermediate Stations, to prevent
the possibility of overrunning the mark from the failure of breaks. It
must be borne in mind that the breaks act much less efficiently in wet or
frosty weather, when it becomes necessary to shut off the steam further
from the Stations. The use of the reversing-lever ought, as much as
possible, to be avoided: it may sometimes be placed in the middle
position (in which the valves do not act), but it should never be
completely reversed unless absolutely necessary for the stoppage of the
train.
At the intermediate Stations, the Stoker should frequently oil all the
bearings not supplied by the large oil-vessels, and fill the oil-cups of
the connecting-rods, slides, &c., and if any of the bearings, brasses,
&c., are hot, they should be more copiously oiled, and eased if
necessary. He should also examine all the working gear cursorily to see
if it is in a complete state; particular attention should be given to the
axle-bearings, and especially those of the cranked axle, which sometimes
become so hot by running as to require cooling by throwing on water.
In case of the driving wheels slipping much in starting from a Station,
the opening of the regulator should be reduced, and only gradually opened
as the wheel bites; the Stoker is sometimes obliged to scatter ashes,
sand, &c., before the wheels: some Engines are now furnished with hoppers
in front, opened by a handle from the foot-board, by means of which sand
may be dropped on the rails in front of the driving wheels.
If slipping is observed to an unusual extent, it may be inferred that
there is not sufficient weight on the driving wheels, and the springs
ought to be tightened by screwing up the nuts of the bearing bolts: or
where the framing is hung to the springs by plain links, the spring pins
must be lengthened the next time the Engine is in the repairing shops. A
deficiency of weight on the front or hind wheels is indicated by the
pitching of the Engine, and should be remedied in a similar manner.
The regulator should be gradually and completely closed, when the Engine
or train pitches or rocks violently,--in passing a series of points and
crossings,--in very sharp curves, especially if double,--in rough parts
of the permanent way,--and in descending planes whose inclination is
sufficient to carry the train down, without steam, at a velocity of 30
miles per hour. In descending such an inclined plane, if it should be
found that the velocity is greater than 30 miles per hour, it should be
reduced by gently applying the break.
On every Railway there is a prescribed limit to the pressure of the
steam, and no circumstance should induce the Engine-man to use steam at a
higher pressure, or in any case to weight the lever, or hold it down for
more than a moment. When there are two safety-valves, that which is out
of reach may be set at the limit of pressure, and the valve next the
foot-board some pounds lower. It is an advantage to have a stop placed
below the lever of the safety-valve on the screw of the spring balance,
to prevent its being inadvertently screwed down to more than the working
pressure.
The steam whistle is obviously intended to give notice of danger: on this
account its use is forbidden on some Railways, excepting on occasions of
extreme emergency; but the variety of modulation of which it is
susceptible has in others induced its adoption as a frequent warning.
When the latter is the case, it has been found a safe measure to sound
the whistle directly the steam has been shut off previously to stopping
at a Station, and to give two short whistles the moment before starting,
to warn parties of the approach and departure of the train. When this
system is practised, the Engine-man should not turn on the full power of
the whistle, but reserve it exclusively for cases of danger.
When near the end of the trip very little fire is wanted, and both
feed-pumps should be turned on for a short distance before arriving at
the Station, unless the Engine is to start again immediately. If it is
intended to remain at the Station about an hour, the water should be
considerably above the middle cock (when the Engine is standing), which
will be effected by keeping on both feed-pumps from a half to
three-quarters of a mile. The safety-valve should, at the same time, be
eased off to 35 lbs.
If the train is brought into the Station by a tow-rope, great care must
be taken to stretch the rope gradually by a gentle advance of the Engine,
which must be stopped at a signal from the tow-rope man.
It would be prudent to conduct the examination described at the
commencement, directly the Engine arrives at the Station, in order to
leave time for any repair which may be required.
When an Engine is running the last trip for the day, no fuel need be put
on for the last 10, 15, or 20 miles, according as the duty is heavy or
light; indeed, the fire may be nearly run out by the time the Engine
stops, if the gradients, &c., are favourable. For a considerable
distance before stopping both pumps should be at work, so that the water
in the boiler may be at or above the top cock when the Engine stops, and
the safety-valve should be eased off to 25 lbs. per square inch.
On stopping over the pit, the fire is drawn by opening the fire-door,
introducing the arrow-headed poker through the fire-bars, and pulling up
two or three of them from the bottom of the furnace, by which room will
be allowed for the rest to be separated, and the fire fall through into
the ash-pan, from which it is raked out by the Stoker. The practice of
blowing off all the water from a boiler by the pressure of the steam
should never be allowed, without an express order from the Superintendent
of Locomotives, when the boiler is unusually full of mud; as, if
frequently practised, it will seriously injure the fire-box and tubes.