Earlier quoted context omitted.
Something like this maybe? http://philly.curbed.com/archives/2014/10/23/korean-company-...
I think it's crazy that the MTA hasn't already done this. Not only would it save a lot of lives, but it would also allow the platform to be climate controlled. You have no idea how many times I've sat there underground for 30+ minutes in sub-freezing or 100+ degree heat.
Furthermore, platform doors require you to have trains that have the doors in the same positions on the car body, which much of the newer subway fleet (R142,R188 & R143,R160,R179) has but the legacy fleet does not. This issue get compounded even more where multiple lines intersect (which is often due to the NYC subway's unique connectedness) requiring that certain stations would need to support 3 or 4 different car classes.