Washington Metro has had this at every station for ages, save for the pedestrian crossing bit. Lights on the platform flash when a train is approaching.

>>132927
More like they weakly dim. Not like anyone pays attention to them anyway, the hot blast of sewage-smelling air is a better warning system :D

>>132928

This is all true.

>>132927
I've seen them, I think they're a great idea! Not so much to keep people from walking off the edge but for when you're standing ready to embark, staring at your phone, they'll blink as if a heads up to be ready