OK, so here is a serious exhaust fan for those concerned: selectable 50, 80, and 110 CFM exhaust, "whisper quiet". Will that do?
The restroom works out to about 67.5 cubic feet. So at its highest power, this fan could totally replace the entire restroom volume about twice a minute! What a rush (of clean air)!
Chuckle: I suppose I might need an outside air intake at the floor level, so this jet engine doesn't pull all the heated or cooled air from the train room out the roof.
