Firing for Beginners
Instructions in Firing for the Beginnerby W. L. French
Reprinted from the "Brotherhood of Locomotive Firemen's Magazine," Volume 35, Number 2, August, 1903, pp. 222-224.
Q. What should a fireman know before commencing a trip?
A. That the condition of his fire is good, the flue-sheet clean, the grates level and free to be moved, and the ashpan clean. If at night, he should know that the lights are in a condition for use and lighted, and that needed supplies are on the engine. While the engineman is held responsible for starting out on a trip without a supply of sand, coal or water, he will appreciate the fireman's taking note of these things also.
He should observe the water level in the water glass and satisfy himself by the use of the blow-off to the water glass and by the gauge cocks that it is a real and not a fictitious level. He should know that the necessary tools for firing are on his engine.
If the weather is not too cold he should wet the coal down. As a rule the deck will be littered with coal and trash; sweep it out and sweep out in front of the seat-boxes. It will give you a reputation for neatness.
Q. What should a fireman do going from the roundhouse to the train in the yard?
A. Keep a sharp watch for switches that might be wrong or cars that do not clear the track being used, and engine and cars moving which the engineman may not see. Do not be afraid to call the engineman's attention to anything you see that is wrong, even if you believe the engineman also sees it. If he is a wise man he will appreciate your watchfulness, even if he does observe the object mentioned.
Ring the bell before the engine is started and ring it while passing through the yard.
Q. Does a stop signal imply danger?
A. Yes, sir.
Q. What should be the condition of the fire before staring out of the yards?
A. The fire should be burning brightly and of sufficient depth not to tear in holes or to be pulled from the grates in starting the train.
If the train is heavy and about all the engine can start, the fire must be heavier than one that the locomotive could start with little effort.
If the steam and water level are low leaving the roundhouse, as they should be, the fire can be built up to the required point with out blowing off.
Where engines are equipped with automatic blow-off the water in the boiler can be blown out to a low level, benefiting the boiler and at the same time allowing the fire to be built up without the engine blowing off steam through the safety valves, as more water can be supplied to the boiler to keep the steam pressure below the "popping" point.
Q. What should always be done before staring an engine?
A. The bell should always be rung.
Q. Should a fireman read the train orders before leaving a terminal and ought he to take notice that they are properly executed?
A. Yes, sir.
Q. Ought a fireman to familiarize himself with the physical characteristics of the division or divisions of railroad on which he is employed and the location of the stations?
A. Yes, sir.
A. Knowing the location, extent and severity of grades and the location of stations he can have his fire at all times in condition to meet the varying needs of the work: a very necessary thing in locomotive service.
Q. What indicates the steam pressure in a boiler?
A. The steam gauge.
Q. In that manner does the steam gauge work to indicate boiler pressure?
A. While there are a number of different types they all may be placed in two classes, one where the steam pressure is exerted against a corrugated diaphragm plate, in the other through the medium of a hollow U-shaped tube.
In the steam gauge using the corrugated plate there is a small chamber to which steam is admitted from the boiler through a small pipe. Corrugations on the plate are circular to give plenty of expansion which it could not have it not corrugated. In the center of this plate is a stud with a bell-crank attachment to the outer end of which a rod is attached to the short lever of a toothed segment, the teeth of which work a small pinion wheel attached to the shaft to which a pointer is fastened.
The plate expanding moves the bell crank and the rod conveys this motion to the pointer through the medium of the toothed segment and the pinion wheel, the expansion varying with the pressure until the maximum is reached.
In the other class the pressure entering the tubes tends to straighten them, and this motion is conveyed to the pointer by a series of levers attached to the points of the U-shaped pipe and the pointer stud.
The pressure shown on the steam gauge is the pressure per square inch above the atmospheric pressure.
Q. Why is the small steam pipe connecting the gauge with the boiler bent, or sometimes twisted in coils?
A. The live steam injures the elasticity of the diaphragm or tubes and the steam condensing in these bends or coils prevents the hot steam from reaching them.
Q. How is the steam shut off from the gauge?
A. By a cock on the boiler head.
Q. Are steam gauges always accurate?
A. No, sir.
Q. What defects might a gauge have?
A. It might show too much or too little steam pressure.
Q. How can this be determined?
A. By testing the gauge, usually against a test gauge that has been tested against a column of mercury.
Q. What is the use for which safety valves are placed on a locomotive?
A. To keep the steam pressure at a safe working limit. This pressure is considerably below what the boiler is designed to carry without rupturing the sheets.
Q. Why is it necessary to use two?
A. If one becomes inoperative the other would act. It is merely an additional precaution against explosions.
Q. Describe the safety valve's action.
A. The valve is held on its seat by a spring adjusted to the desired amount of resistance. When the steam pressure exceeds the resistance of the spring, the valve rises and allows the steam to escape until it is lower in pressure than the resistance of the spring, when it closes. One safety valve is usually set at a higher resistance than the other.
Q. What power is used in locomotive practice?
Q. What is steam?
A. Evaporated water in a gaseous form.
Q. At what temperature of the water does the change take place?
A. Two hundred and twelve degrees Fahrenheit, when the atmospheric pressure is equal to 15 pounds per square inch.
Q. In what manner does the temperature vary?
A. With the atmospheric pressure. As the altitude grows greater and the atmospheric pressure less, the boiling point is lower in degrees of heat, and descending into a denser atmosphere at the earth's surface, the opposite is true.
Q. To what pressure is the steam rising from an uncovered vessel equal?
A. The atmospheric.
Q. What pressure does the steam gauge show?
A. The pressure of the steam above the atmospheric pressure.
Q. Is steam visible?
A. No; what is ordinarily called steam is the steam after it becomes cooled or vaporized.
Q. How is steam used?
A. Expansively; that is, steam being a gas and having the tendency of all gases to expand and fill space, by allowing its escape to be regulated by the valve gear through the cylinders this energy is utilized to drive the pistons and give the locomotive its power.
Q. How is steam generated?
A. By the action of the heat of the fire on the water. At first little steam bubbles leave the sheets and rising to the top of the body of water explode. As the fire becomes hotter the boiling or evaporation takes place more rapidly. The temperature of the water does not rise above 212' F.
Q. What is the composition of soft coal?
A. As a general average it may be taken as 8 per cent carbon, 5 per cent hydrogen and 15 per cent waste substance. This composition varies with the different kinds of coal.
Q. What is combustion?
A. Burning. The union of elements of air, called oxygen, with the hydrogen and carbon of the fuel.
Q. What appearance has a fire at a high temperature?
A. White and dazzling to the eye.
Q. How can such a fire best be obtained and maintained?
A. By firing the coal light and often.
Q. What effect has a large amount of coal thrown on a brightly burning fire?
A. It smothers the blaze down, cools the fire and allows generate gases to escape unburned.
Q. Is this waste?
A. It is. The escaping unburned gas contains heat units that should be used to convert water into steam.
Q. Why should coal be broken into small lumps before firing, to obtain the best results?
A. It ignites and burns more quickly and gives better opportunity for air admission. If a large lump is thrown in it destroys the air admission directly under it, and it burns slower than the small pieces of coal and is often the basis of clinkers.
Q. Outside the waste of fuel, is heavy firing in any manner injurious?
A. Yes; it injures the flues, flue sheet and side sheets, and stay bolts.
Q. What is the estimated waste of coal when an engine is blowing off steam?
A. Four ounces per second, or about 15 pounds per minute.
Q. What can be done to prevent the blowing off of steam when the throttle is closed?
A. Drop the damper and latch the door slightly open. The injector that is not working can be used as a heater. Do not open the fire door to prevent an engine blowing off steam when the engine is working; the injury to the firebox is more than the good accomplished.
Q. Of what use is the brick arch?
A. It maintains the interior of the firebox at a more even temperature and retards the escape of gases from the coal through the flues, thus giving more time for their combustion, and assists in mixing the gases of the coal with the air by directing them up and over the arch.
Q. Of what are arches constructed?
Q. What are the objections to an arch?
A. The brick burn out speedily and if the flues leak to any great extent it must be taken out for the boilermakers to do their work properly. The brick are not expensive and on a whole they are an advantage.
Q. Why does closing the damper lessen the rapidity of combustion in a firebox?
A. The supply of air passing through the fire and fanning it is shut off, the generating of coal gas is diminished, as well as the burning of the solid part of the coal.
Q. Why are grates made so they can be rocked?
A. To shake out the burned refuse next to the grates and keep the fire light and clean, thus offering the best opportunity for the admission of air through the grates.
Q. Is there any rule to determine how often grates should be shaken?
A. No. The kind and amount of coal being used and the manner in which an engine works the fire alone can determine this. Practical experience and observation on the part of the fireman will soon enable him to determine for himself the manner in which to handle the grates to obtain the best results.
Q. What is the effect of getting an ashpan too full of ashes?
A. It shuts off the draft through the dampers, and if allowed to reach the grates may cause them to burn out.
Q. How does the exhaust steam passing through the stack create a draft on the fire?
A. It creates a vacuum in the smokebox, and air entering through the damper passes through the fire and flues to fill this vacuum. In its passage through it loses a certain amount of its oxygen. This process is constant and rapid while an engine is working steam.
Q. What is the use of a blower?
A. to clean up the smoke when the throttle is shut, used with the door slightly open and the dampers down. To obtain steam when necessary on an engine that is leaking, it should be used as lightly as possible at all times.
Q. Name some abuses of a boiler?
A. Allowing the temperature to vary greatly in the firebox, the fire to get heavy, firing heavy and failure to keep the grates loose.
Q. What should be done to keep leaky boilers in the best shape?
A. Fire light and keep the fire from growing heavy, maintain firebox at as near the same temperature as possible and heat feed water when possible.
Q. Will noting the water level in the boiler assist one in firing?
A. It will.
Q. In what manner?
A. By permitting one to fire to suit the needs of the water supply.
Q. What should a fireman do after arrival?
A. Care for any signals displayed, see that there is a supply of water in the boiler and sufficient fire to last the engine until the arrival of the engine dispatcher. If at night put out lights that are not needed.
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