Possibly, but the pressure difference would pop people's ears, moreso than they do already. I'm sure the piston-like effect of moving trains is considered too t

Possibly, but the pressure difference would pop people's ears, moreso than they do already. I'm sure the piston-like effect of moving trains is considered too to help move air around. Question is whether that's enough air movement to offset the heat generated by the trains, after all (and this is secondary school level understanding of thermodynamics), the energy needed to move the train is the train weight itself, plus track friction, plus air resistance. That is, in my head, it costs more energy to move the train than the amount of air that is moved around, so it in itself wouldn't be enough.