We've all seen them mobbing trainless platforms, or standing dumbly in front of open doors- but this bunch are, yes, behind the station. I bumped into them while hunting collectibles: (In the bushes out of frame: a couple dogging, which explains it)
DTG needs to rework the whole passenger thing soon. Currently it's broke and it is broken since years at this point
I noticed this at Aston. I got off and tried to get to street level to cross to the other platform. There was about 50 zombies down there. Probably the queue for drugs knowing some of the fiends at Aston. Also Duddeston has more peds than the whole of the rest of the route combined. Bet none of them pay either.
Remember Carmageddon? Why not a silly zombie mode for TSW where they wander everywhere and you get extra points for taking them out (by train or in 1st person with a handy baseball bat)? It would be a fun halloween thing, and of course the trains would need be suitably "decorated" with zombie goo for each hit.
The TSW passengers look actually more terrifying then Resident Evil Zombies for the most part, especially when they all decide to wear neon-pink baseball caps
MSB has at least one station where this happens. The vast majority of routes I've played do. First time I saw it was early this year. Have a look at the top of the stairs in the underground stations on RT and you'll also see it. The one in the picture from RSN kind of stands out as it's very consistent and in seemingly open space.