This just in, the 7 line extension will have platform doors!
What the hell those? Platform doors are sliding glass doors at the edge of the subway platforms. They create a floor to ceiling barrier between the platform and the open tracks.
What for? They not only provide a safe barrier from people ending up on the tracks, but they also save cooling energy. By keeping the platforms sealed off from the tunnels when trains are not in the station, hot air cannot fill up the platforms. Therefore, the stations are kept cooler, and energy is saved. See what they could look like HERE.
The platform doors are estimated to cost $2 million per station. However, the cost is made up in energy savings.
Perhaps the 7 line extension will clear the way for doors on the 2nd Avenue line to have the doors as well.