Cylinder cocks are valves that release steam condensate (water) that occurs when cylinder temperatures are significantly cooler than that of the incoming steam, typically when the locomotive begins to move. As hot steam comes in contact with a colder surface, liquid water will form which does not compress! As the pistons move up and down, damage can occur if there is too much water in the “compression area”. As soon as the cylinder temperatures rise due to the continuance of incoming steam, the amount of condensate lowers at which point the valves can be closed. Cylinder cocks have very small openings which allow just enough water to be expelled without a drastic reduction in steam pressure, allowing the engine to continue to create power until they are closed for normal running.

There are four manually operated cylinder cock valves, two for each cylinder (top and bottom). The brass valves were purchased online and the linkages, drain pipes, and elbows were fabricated from brass. A simple hand lever opens and closes all four cocks at the same time (up is open and down is closed). The linkage design was inspired from a photo of a prototype Shay running in Cass, WV.