Given that the exact same question is the current top post but for driving instead of transit, I feel this question was needed.
My answer: I saw some guys hooking up a Raclette Grill to the outlet in an otherwise empty German intercity rail waggon. They had it unpacked in one of these 4 person seats with a small table. No idea if that could work or if draws too much power from the board net. I just headed on to the next waggon.
Lol your raclette experience reminded me when we once hooked up an electric cettle on a swiss alpine train to make an alcoholic drink called „fröschli“. It worked great but it also uses a lot less power. :D