送風器和火箱進氣口

空氣中的氧氣是火焰燃燒時不可或缺的；控制火箱的進氣量便能控制燃料的燃燒強度，間接調整火箱的溫度。

The most basic way the air gets fed into the firebox is simply by draft from opening the regulator and propelling the vehicle. As the steam from the cylinders is expelled through the blastpipe, it draws fresh air into the firebox with every cycle. The higher the cutoff setting the higher the draft.

此外，還有兩個裝置能用於調節火箱進氣量：「送風器」和「火箱進氣口」。

Blower is usually operated by a valve. When open, it releases steam from the boiler around the chimney area. This creates draft, bringing more air into the firebox. This is used when there is a desire to increase the temperature of the firebox, but not to accelerate, such as in the case of going downhill or being stationary. Having the blower open while accelerating is wasteful however, because the acceleration draft is superior and the blower in that case simply wastes steam into the atmosphere.

Damper is usually operated by a lever. When closed (pushed down) it chokes the airflow, drastically reducing fire temperature. This is used to reduce steam production when it is no longer needed.