Shame they pick railway stations though. Why not police locker rooms?
Or the city banks! Or the Houses of Parliament!
I'm sure there is far more casual and abundant use of drugs in City banks than there is on or around your common-or-garden railway station, that's for sure.
It wasn't so long ago that some docu-prog looked into drug use in the City and found that tons of toilets in offices and bars, plus bank notes used in that area, had substantial traces of cocaine detected in and on them.