The Purple train ran into the back of the red train that sits to the right of the image. They are in a braking zone. The railing on the right of the track is an emergency unloading zone if a train has to stop in a braking area. From what I can tell this is the next to last braking zone before the train enters the station. Trains entering this braking zone would not generally come to a full stop. But they would if there was a train ahead of them waiting to enter the station.Link
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.