Oooh - according to the NY Times, the MTA has been investigating the possibility of installing floor-to-ceiling glass walls and sliding doors at the Second Avenue subway. Apparently, having walls and doors might "allow substantial energy savings" and "reduce temperatures by about 10 degrees." Whoa, imagine that - no more super hot platforms on those summer days?

The interesting back story is that former NYC Transit President Lawrence Reuter rejected the idea when it was presented during earlier iterations of the Second Ave. subway plan; since he left the agency in February, MTA planners went back to engineering firms to ask them about platform doors. Still, the MTA denies the second look has anything to do with Reuter's departure, telling the Times it's more about energy savings and safety benefits - maybe even more subway efficiency (less track fires from trash!).

One question is how trains will work with the doors; will the subway car's exits line up each time? And there's a quote from Reuter himself: “I definitely discouraged it because it’s a cost item and it’s a maintenance item. It’s only going to apply in a few stations. What good is it going to do if you can’t adapt it to the rest of the system? I didn’t see any benefit, plus it’s going to cost extra money to maintain them.”

Photograph of the Hong Kong subway by Ian Muttoo on Flickr