火箱

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.

火箱內的溫度能透過一個溫度計監控。火箱應保持在剛好足以產生所需蒸汽量的溫度。溫度過低將無法產生足夠的蒸汽，溫度過高則可能導致燃料消耗效增加。

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.

司機員若要精準控制火箱中的煤炭量，可以選用專家鏟子。使用位於火箱門旁的拉桿也能將火箱內的煤炭自當中排出。.