[guard-of-terra]

Your other option is: you press a button in a wagon, ask to call the cops to the wagon with problematic passenger, and on the next station cop patrol is already there on the platform waiting eagerly. And the issue pretty much dies right there. Come on, it's totally doable, isn't it?

P. S. I understand that usage of the word "wagon" makes native english speakers' heads explode.

[BugBrother]

The term is "Swenglish". I am losing control. My Swedish use as much US/English idioms as my English use Swedish idioms. :-(

tunnelbana == tunnel + path/track

tunnelbanevagn == subway car.