Every time I’m on a business trip with the German bullet train ICE, the overhead rack is full of black suitcases. Often there’s another Rimowa case next to my one.
One way to avoid confusion when picking your case from the rack when leaving the train, is to put some kind of unique luggage tag onto your case.
I went one step further and put an URL sticker on the front of the case.

Suitcase with URL sticker
tinkr.de also leads to this website 🙂