Originally Posted by
noglider
Air conditioned subway cars came in the 1980s if I remember right. It made the overall subway riding experience better, but the downside is that the station platforms are intensely hot. The trains spew a lot of heat, and that heats the tunnels as well as the stations. The platforms are hot for weeks after the summer heat is gone because the bedrock retains the heat so well.
I have very often wondered why they don't do a better job of venting the platforms. Besides heat the staleness of the air is not too pleasant. Subways in Europe (and Wash DC?) aren't nearly as bad as NYC even on the hottest and most humid days.
Then there's the issue of walking by or over the vents in the sidewalks. Ugh. Rather fascinating though is 58 Joralemon Street in Brooklyn that looks like a townhouse but is actually a vent and tube access. Seems there are a few of these around NYC.