The AC Turned Off Early?

I feel like the air conditioning on a lot of subway trains was turned off too early.

Honestly, I have no idea how the AC works on the trains.  Don’t know if there is a thermostat or what, but I feel like the AC was cut.  Seems to happen every year.

There was a bit of a cold snap a week ago, so there wasn’t much need for too much AC.  So I think it was cut off on many trains.  Then late last week, it warmed up again, but the AC wasn’t turned back on.

It really gets oppressively hot when theirs no air on the trains.  The heat is one thing, but then it feels like the oxygen in the air is getting thing.  Kind of a panic situation if you are at all claustrophobic.