Zylinderhähne

Wenn den Zylindern kein Dampf mehr zugeführt wird, kühlen sie schnell ab, weil sie baulich von den Wärmequellen der Dampflokomotive getrennt sind. Dampf kann so vergleichsweise schnell in den Zylindern kondensieren. Da Wasser im Gegensatz zu Dampf nicht komprimierbar ist, kann dies, wenn sich genug davon in den Zylindern ansammelt hat, die Zylinder beschädigen und einen katastrophalen Ausfall des Antriebsstrangs verursachen.

For this reason there are cylinder cocks. They are operated by a valve from inside the cab, allowing water to be released from the cylinders. As some of the steam from the cylinder is lost while the cylinder cocks are open, acceleration is reduced. Typically, the drivers open cylinder cocks for a few seconds after being stationary for some time.

Cylinders can also fill with water in a process called priming. This is the case of the boiler having too much water, or running the vehicle with the cutoff set in the opposite direction, causing water to overflow into the cylinders.

See also: Mechanical Powertrain Damage, Water Level, Cutoff