气缸旋塞

Cylinders are steam engine components that house pistons that propel the vehicle. Typically, there are two cylinders in the front of the vehicle, one on each side. They are alternately fed steam from the steam chest , with every full rotation of the driving wheels, in the amount set with the cutoff .

Steam in cylinders pushes the pistons inside, mechanically linked to the driving wheels, propelling the vehicle. The used steam is then expelled through a blastpipe, where it mixes with smoke from the firebox in the smokebox, and together they are exhausted to the atmosphere through a chimney.

当蒸汽不再进入气缸时，它们会迅速冷却下来。这是因为它们与锅炉和燃烧室分开。汽缸中的蒸汽很快又凝结成水。由于水不可压缩，不像蒸汽，如果足够多的水聚集在汽缸中并被活塞推动，它会破坏汽缸并导致灾难性的动力系统故障。

To prevent this, steam engines come equipped with cylinder cocks. They are usually operated by a lever from inside the cab , and allow water to be expelled from the cylinders. However, since steam escapes through the cocks too, they should only remain open for a short time, typically just a few seconds, when the vehicle begins moving from a standstill.

Cylinders can also fill with water if the boiler is overfilled , or from running the vehicle with the cutoff set in the opposite direction.