Remember one thing, the engineer is responsible for the fire, even if he does not make it. He must therefore know when a fire is good and when it is bad, why and what to do.
We shall, however, describe two styles of fire, the thoroughly bad and the thoroughly good. All intermediate grades every man must learn for himself.
How To Build a Bad Fire.
Pile your coal up in the shape of a cone, by shoveling all the coal into the middle of the fire box, and putting as little on the sides as you possibly can.
Such a fire possesses the following characteristics: Uncertainty as regards steam making, positive certainty as regards the destruction of fire boxes and tubes. It generally draws air at the walls of the fire-box, and in consequence, the fire-irons are always in the fire, knocking it about and wasting the fuel.
As such fires are found in the center of the grate, they weigh down the bars and burn them out in the middle in short order. Lastly, the cold air being admitted into the fire-box up the sides instead of in the middle, comes in direct contact with the heated plates and stays, doing them a great deal of damage by causing contraction and expansion.
Take the best engine ever built and let an engineer run it awhile with these "haycock" fires, as they are called—and many do it—you will be sure to find the boiler subject to sudden leakage, either in the joints of the plates or in the stays, the tubes, or the foundation ring. Such engines are always in the repair shop, and because of bad firing and nothing else.
How to Build a Good Fire.
The good locomotive fire should maintain steam under all circumstances of load or weather, should consume its own smoke, should burn up every particle of good matter in the coal, or, in other words, capable of being worked to the highest point of economy.
Such a fire requires to be made at the beginning, and maintained in a form almost resembling the inside of a saucer, shallow and concave, with its thinnest part in the center.