Durango, Co Tri-cocks (3 valves) provide a secondary means of checking the boiler’s water level on a steam engine. These are on the engineer’s side of the backhead of D&SNG 478 (formerly D&RGW 478) in Durango, Co.

Silverton, Co Trains need air for braking, and in the old days it was provided by a steam driven air pump. This one is on D&SNG 486 (formerly D&RGW 486), a K-34 class Mikado (2-8-2).