I smoked once on the S-bahn station (wouldn't imagine it can be allowed on U-bahn), and the security politely informed me with a smile that it's not allowed. In

I smoked once on the S-bahn station (wouldn't imagine it can be allowed on U-bahn), and the security politely informed me with a smile that it's not allowed. In my homecountry I'm not used to any form of security being polite. Not only beer, you forgot gluhwein :)