火室

Firebox is a chamber onboard a steam vehicle, where the fuel is burned in order to heat up the water inside the boiler. Coal powered fireboxes have a firedoor, which the engineer can keep open while shoveling coal inside. The door should be kept closed whenever possible. Even though its effect on firebox temperature is minimal, keeping the door open can cause blowback when entering tunnels, a reversal of the exhaust flow that can draw fire into the cab and be catastrophic for the crew. Blowback can be prevented by keeping the door closed, or by maintaining intense airflow when entering a tunnel.

火室内の温度は、温度計で測定します。必要な量の蒸気を作り出すために、必要なだけの温度を保つ必要があります。温度が低すぎると蒸気が十分に出ず、高すぎると燃費が悪くなります。

Firebox temperature is controlled by the amount of coal and airflow inside it. Simply having no more coal to burn will cause the firebox to cool down, and adding more coal will warm it up if the airflow is sufficient. The amount of draft depends on whether the steam is being admitted to the cylinders, but can also be adjusted by the blower and damper controls.

Having the firebox full to the brim is not always the best choice. Too much coal with too little airflow negatively affects fuel efficiency, resulting in a lot of coal particles getting spewed out of the chimney before they’re fully burned. This is what makes the smoke dark. When there’s less coal in the firebox it burns cleaner, making the smoke color closer to white.

火室内の石炭の量をより正確に制御するために、運転士は給炭量の少ないエキスパートスコップを使用できます。また、火室の焚口戸の隣にある石炭排出レバーを使用して、余分な石炭を捨てることもできます。