Stoker Work Area Stoker Fire Area
"Basic Steam Locomotive Maintenance"
Available from:
The Railway Educational Bureau
A Subsidy of Simmons-Boardman Publishing Corporation,
1809 Capitol Ave., Omaha, NE 68102
Phone 1-800-228-9670
http://www.steam-train.org/steambok.htm
or from:
Locomotive Training Program
Southern Ontario Locomotive Restoration Society
Sample from text book
Southern Ontario Locomotive Restoration Society,
PO Box 20099. St. Thomas, Ontario. N5P 4H4
Practical Locomotive Firing
In the USA, the National Locomotive Inspection Law is supervised and
enforced by the Bureau of Locomotive Inspection of the Interstate Commerce
Commission. The law provides that practically all coal burning steam passenger
locomotives, weighing 80 tons or more on drivers, and coal burning steam
freight locomotives, weighing 87 1/2 tons or more on drivers, built after
April 15, 1939, shall be equipped with a suitable type of mechanical stoker
that shall be properly maintained.
The principles underlying the burning of fuel in the locomotive firebox
are the same whether the locomotive is hand fired or stoker fired. Stokers
used on locomotives are designed to place the coal in the firebox mechanically,
a good deal as it would he placed by skillful hand firing.
The stoker is controlled manually by the fireman. Consequently, a fireman
must understand the principles of hand firing if he is to do a successful
job of stoker firing.
The stokers on many engines are installed so that the locomotive can
be fired by hand in case of a failure of the stoker. This is another reason
why all firemen should understand the principles of hand firing, even though
they are regularly assigned to locomotives which are stoker fired.
Practical Locomotive Firing
HAND FIRING
GENERAL
1. With the one exception of wages, the greatest single expense
incurred in operating a railroad is for fuel. The cost of locomotive fuel
on a fair-sized; railroad System (1500 locomotives) will run about $15,000,000
a year. This amounts to more than $40,000 a day; in fact, on a busy division
the cost of fuel per day may be from $5,000 to $10,000. This fuel cost
is so important that most railroads employ special men whose chief duties
are to investigate the use of fuel, and plan methods whereby fuel can be
used more economically. Although some fuel necessarily is wasted in railroad
service, wasteful practices are being corrected wherever practicable.
2. Every employee of a railroad should be interested in this
proposition, as this one field offers opportunities for very large economies,
which, if effected, would be a considerable aid in our national conservation
program.
3. Each scoopful of coal wasted represents about two cents burned up
or thrown away unnecessarily. Fifty scoopfuls wasted on a trip represent
just as much of a loss as would occur if the treasurer of the company tore
up and threw away a one-dollar bill.
4. On every railroad the problem of fuel economy is largely
in the hands of the engineers who operate the locomotives. If an engineer
is interested in this subject and insists on his fireman firing according
to correct principles, fuel will be saved on each trip. An employee
owes it to his company to do this. On the other hand an engineer, who allows
his fireman to waste fuel unnecessarily, not only causes unnecessary expense
to the company but also aids the fireman to form wasteful habits. Careless
firing results in a dirty fire, a poor steaming engine, and possibly may
end with an engine failure.
5. Entirely apart from the question of economy comes another
question of particular interest to the fireman; namely, that of the labour
performed in doing the day's work, or in making a trip. It is an indisputable
fact that the easiest, least labourious, and, most economical way to fire
a locomotive is according to the correct principles of combustion, all
facts and arguments to the contrary notwithstanding.
6. It is true that many first class firemen do not understand
the principles of combustion. They have learned from practical experience
to apply these principles without knowing the reason for so doing. The
fact remains, however, that the man who shovels the least coal on the trip,
who seldom has to clean his fire, who does not have to perform the extra
labour of using a slice-bar or a rake is the man who is firing according
to correct principles.
7. This text will deal with the practical work of firing. Certain
statements about what takes place in the firebox of a locomotive will be
made without giving the reason why. These reasons can be obtained from
a following text on the
THEORY OF COMBUSTION (Unit No. 2).
8. Certain fixed principles must be borne in mind during the
study of this text on practical firing. To produce heat in a locomotive
firebox, three conditions are necessary -- and only three: First, there
must be a SUPPLY OF FUEL; second, there must be a plentiful SUPPLY OF AIR;
and third, the air and the fuel must be brought together at a TEMPERATURE
AT WHICH THEY WILL BURN.
9. The combustible part of soft coal consists of coke (CARBON)
and gases. When a shovelful of this coal is thrown on a fire, the gases
are driven off by the heat, while the coke remains on the grates. Both
the coke and the gases will burn; but before any burning can take place,
they must be supplied with air at what is called the igniting temperature.
Air is composed, in part, of a gas called OXYGEN, which is the necessary
element required for burning the coke and the gases. The burning will not
take place until the fuel and the air are heated to a certain temperature,
called the IGNITING POINT.
10. The fact that all or a certain part of the air is absolutely
necessary for burning can be proved by experimenting with a tallow candle.
If the candle is lighted, it will continue to burn as long as plenty of
air is supplied to it; but if a milk bottle is placed over the candle,
the flame will begin to smoke, and will grow long and slender. As soon
as the limited amount of air which the bottle contained has been used up,
the burning will stop.
11. If too much air is supplied to a fire, it will interfere
with the burning. This can, be demonstrated by blowing on the flame of
a tallow candle. Blowing gently will not, apparently, reduce the flame
very much; blowing steadily and strongly will almost put the
flame out; and a sudden, sharp breath will extinguish it entirely.
The application of this principle will be spoken of later.
12. The statement that the air and the fuel must be brought
together at a temperature at which they will burn also can be illustrated
by means of the candle. Before the candle is lighted, fuel is present surrounded
by a plentiful supply of air, but the condition of proper temperature is
lacking. The fuel of the candle must first be heated to a temperature at
which it will start to burn. When the candle is burning, the action that
takes place during the burning supplies sufficient heat to maintain the
fuel at the burning temperature However, if this condition is interfered
with, as was illustrated by blowing the comparatively cold air from the
lungs against the flame, the temperature is reduced below this burning
point and the flame will go out. The burning will not begin again until
the temperature has been raised to the burning point once more.
13. With the three conditions of fuel, air, and proper temperature
present, burning always will take place, whether it be in a locomotive
firebox, in the open air, or in the finest home or office; but, with any
one of these conditions lacking, burning absolutely will not take place.
14. When burning does take place, the fuel disappears, with
the exception of the ash and the dirt that were in the coal. This
disappearance of fuel is due to the fact that in the process of burning,
a chemical change takes place by which the air and the fuel unite to form
gases. The gases in a locomotive firebox are drawn out through the flues
into the smokebox, and from there pass out through the stack with the exhaust.
During this changing process, the heat necessary for steam-producing purposes
is evolved.
15. There are many different kinds of fuel which burn in many
different ways, as will be explained in the text on the Theory of
Combustion. However, the fireman who thoroughly realizes the facts
set forth above can understand most of the actions that take place in a
locomotive firebox.
16. In firing a locomotive there is one condition that is of
prime and absolute importance. The locomotive should be kept hot at all
times and under all conditions, without reference to economy, method of
firing, or any other consideration. This is because of the fact that a
locomotive must pull its train and get over the road. Loss of time on the
road usually is more costly than waste of fuel. When a fireman has learned
to keep his locomotive hot, then he should begin to study methods of doing
this as economically as possible. The fireman should remember that the
easiest and least labourious method to fire a locomotive is the economical
way.
17. Any fireman should be willing to study and practice fuel
economy, when he realizes that this will fit him to do his work with the
least expenditure of labour. To state the case plainly, the fireman who
uses the least backbone and the most brain work gets over the road with
the least labour because of the fuel he saves.
18. So many locomotives are equipped with stokers that many
firemen today have little practice in hand firing. All of the principles
of hand firing taught in this text apply to stoker firing. Even if a fireman
is regularly assigned to a run where the locomotives are stoker fired,
he should give thought to the possibility of bringing the train in by hand
firing in case of a stoker failure. This can be done on many locomotives
by a skillful fireman. The stokers on some locomotives are so designed
that hand firing is not practicable. Even the most skillful fireman seldom
is able to produce as much steam by hand firing on a large locomotive as
can be produced when a stoker is working to capacity.
19. The economical firing of a locomotive depends upon a great
many things other than the skill of the fireman. No matter how skillful
the fireman may be, if the condition of the locomotive is such that suitable
conditions for the burning of the fuel cannot be
obtained, the firing cannot be done either properly or economically.
The locomotive must be designed so that the boiler has
sufficient capacity to supply the amount of steam being used in the
cylinders. The grates must be designed so that the proper
amount of air can pass through them to the fire. The ashpan must be
designed so that a sufficient supply of air can get to the grates, and
it must be arranged so that it can be cleaned quickly and easily, in accordance
with the Federal Law. The locomotive must be "drafted" properly, so that,
with a proper depth of fire on the grates, a sufficient amount of air will
be pulled through the fire, and pulled through evenly, so as not to 'tear"
it in some places and let lie dead in others. The draft also must be regulated
in accordance with the class of fuel that is being used.
20. The proper drafting of the locomotive includes the proper
adjustment of the smokebox appliances, and in addition, requires that the
exhaust-nozzle be of such size and shape as will give the correct amount
of draft without creating excessive back pressure in the cylinders. Also
it presupposes that the smokebox is airtight except at the stack and flues;
that it is self-cleaning or else is kept cleaned out; that the netting
is not stopped up; that the flues are not plugged up; that the firebox
sheets and flues are not leaking; and that there are no steam leaks in
the exhaust pipe, steam pipes, or the superheater connections in the smokebox.
21. The engineer and fireman most work together to produce
best results. The manner in which an engineer handles the reverse lever
and the throttle, the care he takes to prevent the drivers slipping, the
help he gives the fireman in the way of advance notice of slowdowns, stops,
etc., all have a corresponding effect on fuel economy.
PREPARING FOR
THE TRIP
22. With a locomotive in proper condition, as outlined above,
the fireman has a number of duties to attend to before beginning the actual
work of firing. On reporting for duty, he must examine the bulletin board
and conform with other operating department rules. Then he must ascertain
that he has the proper tools (particularly a good shovel and a coal pick)
on his engine, as well as sufficient oil, waste, and other supplies for
the trip. He should see that there is a full supply of coal on the tank,
as well as a full tank of water and a full supply of sand. Also, he should
check to make sure that he has the proper flags, lamps, torpedoes, etc.
He should inspect the firebox to see that the flues and firebox sheets
are not leaking. A similar inspection should be made of the ashpan, ashpan
blowers, and the dampers and slides, to see that they are in a condition
which complies with the federal law. He should make sure that the ashpan
slides and connections are locked securely, so as to prevent the dropping
of fire.
23. While attending to the various duties referred to above,
he should begin to prepare his fire for the trip. He should move the grates
to see whether they are working properly. This will assure him that he
has a shaker bar, and will allow him to ascertain whether the fire has
become dirty or clinkered while the engine was standing in the roundhouse.
If the fire is banked, he should spread the live coal over the grates and
cover it with fresh coal, using the blower just enough to get the fire
burning properly and building the fire up as gradually as time permits.
Forcing the fire too hard at this stage is likely to cause it to clinker,
wastes fuel, and causes the unnecessary production of smoke and gases around
the roundhouse. The method of procedure is about the same when a new fire
has been kindled with oil, wood, or other kindling material.
24. In order to make the easiest and most successful trip under
the conditions that exist, the fireman should have some knowledge of the
locomotive--how it is drafted; how it burns the fire; how the engineer
handles the throttle and reverse lever; how he pumps the engine; what kind
of coal is on the tender; what kind of a train he is going to pull; how
many cars are in the train; the tonnage of the train; what the grades are,
and where they are located; and, if on a scheduled run, the speed that
is required between different points in order to make the time.
25. Knowledge of all of the above-mentioned conditions
bears directly on the ease and success with which the fireman will get
over the road. Most of the things mentioned can be learned only by experience,
and an observation of conditions as they arise; but no fireman who wants
to be successful should overlook the necessity for giving careful attention
to these details.
PROPER FIRING UNDER
PROPER CONDITIONS
26. In describing the actual work of firing a locomotive, it
is necessary to assume that the engine is drafted properly, and is in
condition to burn the fuel furnished
economically. In the discussion which follows, it is assumed that these
conditions exist.
27. In starting out, the fireman should endeavour to have a
LIGHT fire, a LEVEL fire, and a BRIGHT fire. These are the three
conditions which always should
exist in the firebox. The thickness of the fire should be regulated by
the class of fuel, the drafting of the engine, and the weight and schedule
of the train.
28. The fire must be LIGHT, because the amount of air that can
be supplied in a locomotive firebox always is limited. If the fire is too
heavy it is practically impossible to get sufficient air through the bed
of fire to burn properly the large volume of gas that is liberated from
the fuel. When fresh fuel is thrown on such a fire, there is sufficient
heat in the firebox to drive off the gases from
this fuel and partially burn them; however, there is neither the proper
igniting temperature present nor the requisite air supply to
burn them completely.
29. As soon as the gases are liberated from the coal,
they are pulled toward the flues by the exhaust. These gases are the principal
heat producing part of the coal. If the conditions in the firebox are such
that, these gases are drawn through the flues before they are completely
burned, a large amount of fuel is wasted. These gases will be burned before
reaching the flues if the proper conditions are present in the firebox.
One indication that the fire is too heavy is a continuous trail of smoke
(partially burned gases) from the stack.
30. If the fire is too light, the draft will pull such
a large volume of cold air through the bed of fire that the temperature
of the gases will not reach the igniting point, and proper burning will
not take place. This condition can be ascertained by observing the fact
that the steam pressure immediately falls under such conditions, and no
smoke appears at the stack, even when fresh fuel is thrown on the fire.
31. The fire must be level for the reason that, with a
locomotive which is drafted properly, there is an equal pull of air through
the entire area of the grate. If the fire is banked at one place and low
at another, the air, seeking the easiest channel for entrance, will, for
the most part, pass through the place where the fire is light. Very little
will pass through the place where the fire is banked. This gives an unequal
distribution of air to the fire, and creates the same effect on one part
of the fire as though the draft were too light, and on the other part as
though it were too heavy. This is further and better illustrated in a case
where there is a hole in the fire. In such a case, nearly all of the air
passes through the hole, and very little through the rest of the fire.
The steam pressure immediately responds to this condition; and the pressure
cannot be regained until the fire is leveled over, and the proper conditions
for burning are obtained once more. A condition of this kind not only lowers
the steam pressure, but also is very hard on the boiler.
32. The fire must be bright, because it is absolutely
necessary at all times to keep the temperature in the fire box up to the
igniting point of the gases. The maximum temperature that can be maintained
in a locomotive firebox is about 2500 degrees (Fahrenheit). The igniting
temperature of the gases is about 1800 degrees. These figures show that
there is comparatively little range between the maximum temperature that
can be maintained and the point at which the gases will not burn, due to
the .....
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