"Fahrkartenloeser" means "ticket-buyer".
Public transport in Germany operates on kind of an honor-system here. There are no turn-stiles and tickets are only checked randomly. So, it's possible to ride for free. But if you get caught, you get fined $30. It's kind of an interesting gambling game to play: Save a $2 ticket at the risk of a $30 fine. It's completely possible to ride 15 times and not get caught, but then again, you could get caught twice in one day. It's a cruel little psychological game the ticket-checkers play: 2 or 3 board the train in plain-clothes. When the doors close and no one can escape, they stand up, display their badges, and with a sadistic grin announce "A very good morning to you. Your tickets please." You can see the look of panic in eyes of those who dont have tickets. Well anyway, a Fahrkartenloeser is someone who cant handle the risk of Schwarzfahren (riding w/o ticket). That's me. It makes me too nervous ;-)