Re: Rotary air

Correction Cokerman - OY and OM have 11" pumps. Single lung pumps came in 8", 9 1/2" and 11" sizes. The Rotaries are set up to handle the automatic air on the train, but for techical reasons we never did. The lead locomotive handled the automatic air on the train. The air compressors have to function on each locomotive in order for the brakes on each locomotive to work. In other words, there has to be main reservoir pressure in each locomotive for the brakes to function on each locomotive. Diesels MU the main reservoirs together in a lashup, but steam locomotives don't.
The piston rings on the OY's flanger air cylinder leak badly, and when the flanger is raised, a lot of air is lost that way. It would be a rather involved project to fix this. A project that never got very high priority.
A single lung pump has a much louder exhaust than a compound pump, which is another reason it is so much more noticable on the tape.