汽門

汽門是蒸汽機車 上的控制裝置，與其他動力 種類車輛上的油門 功能相當。汽門用於調整自鍋爐 注向「汽室」的蒸氣 流量。再透過操作逆轉機 控制「汽室」蒸氣進入氣缸 的方向，進而驅動車輛。

The regulator does not directly control a vehicle's acceleration. Rather, steam chest in combination with cutoff does, which is why it has a dedicated gauge to read pressure from. When the regulator is closed, steam stops flowing to the chest, but the vehicle stills accelerate until the chest runs out.

Delay in regulator operation doesn't need to exist only when closing it. If a vehicle uses an early version of superheaters, time it takes from opening the regulator until the steam chest start charging is delayed, too.