Introduction to the Steam Locomotive
The object of this
page is to help you become more proficient in the performance of your
duties as an Engineman.
It is hoped the information contained here, which
is based on basic principles, will stimulate thought and interest in
the steam locomotive with a view to efficiency, safety and good enginemanship.
Cleaners should take every opportunity to learn
as much as possible about the workings of the locomotive in preparation
for his/her Firemans exam, asking questions of Drivers, Firemen, and
Fitters and attending Mutual Improvement Classes and Training courses
run for their benefit.
SAFETY
The most important consideration of all staff
is that of safety.
All new staff should make themselves familiar
with the sections relating to safety in the Rule Book at the earliest
opportunity.
When joining a locomotive you should always check
the following:
1. Water in the Gauge Class.
2. Handbrake hard on.
3. Regulator shut.
4. Reverser in mid-gear.
5. Cylinder drain cocks open.
When working in the loco yard, don't pass
between buffers when they are close, (at least 6ft apart), taking particular
care when shunting is taking place. Don't jump or stride across
pits, even if walking round them takes longer.
Never jump off locomotives, take your time and
climb down; you could catch your overalls on a lamp iron or other protruding
objects
Keep your working area tidy and avoid leaving
obstacles where someone could trip over them.
When working on or preparing locomotives for
service, you should never go underneath or in between the motion without
using a "Not to be moved" board placed prominently on the
locomotive. Further, you should chock the wheels and ensure that all
staff working on that locomotive are aware of where you are. Never use
or move any footplate controls without first checking that it is safe
to do so.
When throwing out hot fires, smokebox and ashpan
ash, take extra care. If you are in the area whilst loco disposal is
being carried take care when walking past the locomotive.
REMEMBER. THINK SAFETY, ACCIDENTS CAN COST LIVES
THE BOILER
The boiler consists of a steel shell which includes
the boiler barrel, the outer firebox wrapper plate, the back plate,
throat plate, smokebox tube plate, also the inner firebox and smoke
tubes.
The inner firebox is supported from the outer
firebox by the foundation ring at the bottom, by the crown stays at
the top and the palm stays between the firebox tube plate and the bottom
of the boiler barrel. In addition, the inner and outer firebox plates,
back plate and throat plate are stayed together by about 1,000 steel
or copper stays at approximately 4" pitch and longitudinal stays
between the boiler back plate and smokebox tube plate. when the boiler
is fitter with a superheater, a number of large flue tubes (approximately
5" in diameter) are fitted, in which the superheater elements are
placed.
THE SMOKEBOX
The smokebox is an extension at the front of
the boiler barrel, which together with the blast pipe and chimney form
the means of inducing air required for combustion to the firebox.
Apart from the chimney orifice, the smokebox
is airtight. Other fittings in the smokebox are: main steam pipes, blower
ring, brake ejector exhaust pipe, washout plugs and where fitted, superheater
elements.
When preparing or disposing a locomotive, the
crew should always check the smokebox to see if any of the fittings
are leaking or are displaced from their correct position.
WATER GAUGES
Water gauges are mounted on the boiler back plate
and are positioned so that when the water is in sight at the bottom
of the glass, the firebox crown is covered. (See Figure 2 - Water Gauge)
When working under normal conditions the water
level should be kept in sight in the top half of the glass and before
descending or ascending steep gradients, a higher level should be carried.
Running with too high a water level can cause
priming.
PRIMING
The term "priming" describes a situation
where water is carried with the steam into the cylinders, resulting
at best in an adverse effect on lubrication and at worst severe damage
to pistons, piston rods or cylinder covers, due to the incompressibility
of water.
Priming is associated with an excess of indissoluble
solids or salts in the feed water, a sudden demand for steam or too
high level of water in the boiler. These causes can largely be avoided
by regular boiler wash-outs and sensible engine management by the Driver
and Fireman.
BLAST PIPE
Exhaust steam after leaving the cylinders passes
through the exhaust passages to the blast pipe cap, where it is slightly
throttled so as to form a jet. The cap and the chimney are fixed on
the same centre line and are proportioned in relation to one.another
so that the escaping jet of exhaust steam, when passing through the
chimney, carries with it waste gases from the smokebox. Due to its air
tightness, a partial vacuum is produced within the smokebox, thereby
pulling air through the grate, the fire and the tubes. For this reason,
the smokebox door must be airtight, the blast pipe centred with the
chimney and the blower ring seated properly.
BRICK ARCH
Erected above the grate and immediately below
the first row of tubes, the arch slopes upwards towards the firehole
door. Its purpose is to direct unburnt gases towards the firehole door
to mix with air entering there to ensure complete combustion.
The brick arch works in conjunction with a baffle
plate fitted in the firehole door; this directs air into the path of
the flame and gases to complete combustion and burn off excessive smoke.
Further, the baffle plate directs the relatively cold air entering the
firebox away from the tube plate.
SAFETY VALVES
Safety valves are fitted to prevent the boiler
pressure from exceeding the registered working pressure for which the
boiler is designed.
Older locomotives are usually fitted with simpler
types of safety valve
(Ramsbottom or Salter), but all work on the same
principle of a valve held
on its seating by a spring which can be adjusted
to the required pressure.
More modern locomotives are fitted with the Ross
"pop" pattern.
FUSIBLE PLUGS
Fusible plugs are screwed into the firebox crown.
They are made of brass and have a lead core which
will melt at a comparatively low temperature. If the water level in
the boiler drops too low and uncovers the plug, the lead core melts
and allows steam to escape into the firebox, which acts as a warning
to the loco crew.
Should this occur, both injectors should be put
on immediately and steps taken to remove or deaden the fire.
WASHOUT PLUGS AND MUDHOLE DOORS
Washout plugs and mudhole doors are fitted to
boilers to facilitate cleaning and inspection of the water spaces.
They should be checked for signs of leakage before
a locomotive is lit up. Under no circumstances must washout plugs be
removed by Firelighters to fill boilers with water.
BLOWER
The blower consists of a perforated ring fitted
around the top of the blastpipe cap. Its function is to create a smokebox
vacuum for the following purposes.
a. To increase draught on the fire when the locomotive
is stationary, in order to raise steam pressure.
b. To clear smoke.
c. To counteract blow back of the fire.
DOME
The dome is situated midway along the top of
the boiler barrel and houses the regulator valve and is also the take
off point of steam for the auxiliary controls e.g. injectors etc.
HOPPER ASHPANS AND ROCKING GRATES
Hopper ashpan doors should always be opened prior
to dropping the fire during disposal, to prevent hot fire from damaging
the ashpan. When using this method of disposing of the fire, it must
be undertaken over an authorised disposal point and all clinker on the
firebars broken up using the fire irons before being dropped.
INJECTORS
The injector is an appliance for delivering feed
water to the boiler. In its simplest form it embodies three essential
cones; the "steam" cone, the "combining" cone and
the "delivery" cone. The steam cone admits the steam from
the boiler to the injector, guides it in the direction in which it should
flow and limits by its bore, the amount of steam passing through.
Steam leaving this cone comes into contact with
the water from the tank/tender, is condensed by it and passes into the
combining cone. when steam is allowed to expand in the steam cone from
a higher to a lower pressure, a certain amount of heat is available
for conversion into work and this is spent in giving velocity of the
steam itself in the direction of its flow. The first point to remember
is that the change from pressure energy to velocity energy is brought
about in the steam cone.
In the combining cone, the slowly moving water
combines with the swiftly moving steam and the function of this cone
is to ensure that the steam jet is condensed by the water. The cooler
the feed water the better the condensation of the steam. The combining
cone is convergent in shape, the bore of the cone decreasing with the
result that the jet consists, at its inlet end, of a mixture of steam
and water, and at the outlet of a solid jet of hot water flowing with
high velocity into the delivery cone. Between the combining cone and
delivery cone, is a gap known as the overflow gap, through which excess
steam and water are passed in the starting and finishing operation.
The second point to remember is that the combining
cone effects the complete combination of the steam and water into the
solid jet by the condensation of the steam and the transference of its
energy to the water.
The delivery cone is so constructed that the
change from velocity to pressure energy takes place as uniformly as
possible. The momentum of the jet, which is greatest at the smallest
diameter of the delivery cone, is gradually reduced in velocity and
increased in pressure sufficient to overcome the boiler pressure on
top of the clack valve. The temperature of the feed water is usually
increased by about lOOoF in passing through the injector.
The third point to remember is that the function
of the delivery cone is to convert the velocity energy of the combined
jet into pressure energy.
When using an injector, loco crew should pre-warn
any staff standing or working near to the overflow pipe, before starting
an injector. Further caution should be taken when approaching signalmen
on the ground that are collecting/exchanging the train staff or token.
Prior to using the injector, the loco crew should
ensure that the footplate watering hose tap is off and that the hose
is stored clear from the footplate area.
Causes for Injector failure
1. Dirt or scale on injector cones or excessive
wear or distortion of cones.
2. Air leaks in the water supply.
3. Feed water supply blocked. i.e. rags or foreign
matter in the tank sieves.
4. Feed water too hot.
5. Clack valve not seating properly.
DUTIES OF STEAM RAISER
Note : Only those who have been passed as competent
are authorised to light fires in steam locomotives.
Before lighting a fire in a locomotive, the steam
raiser should check the following:
On the footplate
Sufficient water in the boiler.
Handbrake on.
Reverser in mid-gear.
Cylinder drain cocks open.
In the firebox
No obvious leaks from the fusible plugs, tubes
or stays.
Brick arch complete.
Grate area clean.
In the smokebox
No obvious leaks from the tubes or washout plugs.
Clean smokebox floor.
Close and tighten smokebox door to make airtight.
Around the locomotive.
No obvious leaks from mudhole doors or washout
plugs.
Clean ashpan.
Chimney cover removed.
IF IN ANY DOUBT DO NOT LIGHT UP THE LOCOMOTIVE
If the water level is considered to be too low
when the locomotive is examined, it is often possible to fill the boiler
with water by screwing the special adaptor into the injector overflow
pipe and connecting up a hose from the water supply in the loco yard.
If this does not work, DO NOT attempt to remove a washout plug on the
boiler for the purpose of introducing water. REPLACING A PLUG IS A SKILLED
OPERATION, ONLY TO BE PERFORMED BY AUTHORISED STAFF.
Useful tips when carrying out firelighting.
Close dampers; this reduces the amount of smoke.
Spread small amount of coal on grate area and
in back corners of the firebox.
Throw in lighted paraffin soaked rags, but do
not use an excessive amount of paraffin, as it will drip through the
firebars and into the ashpan, using up the available oxygen before the
air reaches the fire on the grate. A small amount of firewood can be
used to assist in getting the fire started, but in general coal placed
on burning rags will suffice.
Build the fire up slowly - a large amount of
coal will tend to black out the fire and hinder proper combustion.
Apply the blower when a few pounds of steam pressure
is available, with the aim of attaining 50psi of steam one hour before
the locomotive is due off shed. More than this with a large fire will
result in a wasteful use of fuel and constant blowing off at the safety
valves.
CHANGING A GAUGE GLASS
1) Close steam and water cocks.
2) Open drain cock(s) (turn handle 1/4).
3) Remove protector glass.
4) Remove old or broken glass.
5) Remove top and bottom nuts and clean out old
washers.
6) Remove cap nut (some cap nuts have also a
ball valve inside also remove valve if fitted).
7) Clean out fittings at top and bottom.
8) Feed the new gauge glass through top of fitting
and fit the following as you pass the glass through:- washer, top nut,
bottom nut, washer.
9) Holding the glass down fit bottom nut and
top nut with their washers (don't over tighten the nuts as you might
break the new glass).
10) Replace cap nut and ball valve if fitted.
11) Replace protector glass.
12) Open water cock slowly.
13) Open steam cock slowly.
14) Close drain cock .
15) If any of the nuts are leaking close the
water and steam cocks, open the drain cock(s) remove the protector glass.
Now it is safe to tighten any leaking nuts.
16) Now go back to stage 11.
DUTIES OF FIREMAN
Note Only those who have been passed as competent
are authorised to light fires in steam locomotives.
After booking on duty at the appointed time and
reading the operating notices, the Fireman should1 ascertain which locomotive
he is rostered to work and upon joining that locomotive make the following
checks.
1. Water in the Gauge Glass.
2. Handbrake hard on.
3. Regulator shut.
4. Reverser in mid-gear.
5. Cylinder drain cocks open.
6. Sufficient feed water in the tank/tender.
Under no circumstances should any controls be
moved without first checking that fitters or other staff are not at
work on the locomotive. All staff should particularly look out for "Not
to be moved" boards.
Following these checks, the Fireman should draw
from the appropriate locker, the tools, lamps, oil bottles, oil feeder,
detonators1 coal pick, and shovel.
The lamps should be cleaned, filled with lamp
oil, trimmed and where necessary lit. The oil bottles should be filled
with the appropriate oil (taking care to put the right oil in the right
bottle), wiped clean and with the tools and detonators, placed in the
loco tool box, where fitted.
The Fireman should check that there is sufficient
sand in the sandboxes and sweep away all ash and sand from the running
plates. Any spilt coal on the locomotive roof should be removed and
where necessary the coal in the bunker/tender trimmed, to prevent it
from spilling over the edge.
Fire irons should be checked to see that they
are safely stowed on the running plate or tender as appropriate. It
is the Firemans duty to clean the footplate, making sure that gauge
glasses and protectors are clean, that you can see out of the windows
and that every thing is clean, tidy and safe. Remember, if you have
to spend all day on a locomotive, a clean footplate is much nicer and
will no doubt be much appreciated by your driver.
When working trains, the Fireman should endeavour
to keep a good head of steam and plenty of water in the boiler, at the
same time keeping smoke to a minimum, particularly in station areas.
The Fireman should, when not engaged in other
duties, also assist his driver by keeping a good lookout for signals,
obstructions on the line and anything untoward with the train.
Firemans duties also include the coupling and
uncoupling of trains, together with taking water. Care should be taken
when undertaking these duties to prevent limbs or clothing being caught
up.
On returning back on shed after work, you should
ensure that the feedwater in the tank/tender is full and that the boiler
has sufficient water to be lit up for its next turn of duty.
The Fireman should then examine and empty the
contents of the smokebox -throw out the fire (not forgetting to check
the condition of the brick arch, tubes, stays, fusible plugs and grate)
and clean the ashpan. With the latter, it is important that water is
used to dampen the ash to prevent abrasive dry ash from getting on the
motion. Any defects found should be reported to your Driver,
The locomotive should be left in a clean and
tidy condition, as you would wish to find it, with the handbrake on,
regulator shut, reverser in mid-gear, drain cocks open, and the blower
control shut. During Winter months additional frost precaution duties
will be required to be carried out and these will be listed on the notice
board,
The lubricator should also be turned off, dampers
and firehole doors shut to prevent cold air rushing through the boiler
and causing excessively fast cooling down of the firebox and tube plates.
All tools, lamps (extinguished), detonators,
coal pick, shovel and oil bottles should be returned to the appropriate
locker, which should be locked and the key returned to the normal place.
When everything is in a satisfactory condition,
you may then book off duty.
These few notes are only intended as an introduction
to the steam locomotive and its working and new members of staff would
do well to ask any questions they may have, to drivers and firemen,
most of whom will be willing to explain the working of the engine.
It is also worthwhile to spend time working in
the shed on engines under repair and undergoing restoration, to see
how the mechanics work. There is also no reason why you should also
not turn up and help the duty cleaner on days when you are not booked;
the more time you spend with engines the faster you can learn.
There are also some good books available which
contain a wealth of information relating to the steam locomotive and
railway operation.
Those recommended are
"A Manual of Steam Locomotive Restoration
and Preservation" by D.W. Harvey "Raising Steam" by Dennis
Griffiths
"Red for Danger" by L.T.C. Rolt
"The British Transport Commission Handbook
for Steam Locomotive Enginemen" sometimes referred to as the black
book.
Other booklets and publications of interest are
also available free of charge from the Operating office.
TAKE CARE - WORK HARD - ENJOY YOURSELF!
