Air conditioning is another reason that our subway system is way behind other countries, but I understand that ours is a lot older which makes it hard to change things than if you’re building from scratch. In Japan the subway stations are air conditioned, and I think their system is even larger than New York’s by a long shot. We’re so spoiled nowadays because no a/c in an subway car is a minor inconvenience whereas however many years ago it was strictly the reality. Some train platforms are particularly unpleasant during the summer. Canal street would have to be on top of my list because of the addition of overpowering smell enhanced by the heat.