Glossary Results for Word "Drain Cock"
|Drain Cock||When steam enters a cold cylinder it condenses into water. Water is incompressible, and so Drain Cocks are left open when an engine starts off, and closed once the engine is on the move. It is steam escaping from the Drain Cocks that gives the very distinctive plume of steam at the front of the engine (just above track level) when a steam train departs. Drain cocks are operated from the footplate. Also known as Cylinder cocks.|