"Does this mean every City fan with a ticket has a free train ticket from Dusseldorf to Dortmund?"
YES!!!
The train goes via Düsseldorf-Flughafen, Duisburg, Mülheim ( near Oberhausen ), Essen, Bochum to Dortmund.
When you arrive in Dortmund, you leave the station and visit ( 5-10 min. to...