When I first rode the train in 2009 there was a plastic rack in the Cafe car that holds train schedules, advertisements, and a special form we affectionately called "The Blue Card". Basically a complaint form to report bad service, bad quality etc.
We used to joke about filling these out every time the cafe car ran out of Stone Arrogant Bastard beer, which happens often on Fridays. But I think I used this really only one time when a certain person was extremely rude and insulting. It disappeared forever shortly after that.
The image you see to the left is that of perhaps the last remaining copy.