There currently is one option to travel by night train from Bischofshofen (Austria) to Bremen (Germany), taking between approximately 14 and 15 hours: Namely the UEX 1310 operated by UEX.
UEX (Urlaubs-Express) runs seasonal night trains and car-carrying trains between Germany and Austria.
You can choose a seat, a couchette berth, a whole couchette compartment, a private sleeper compartment or connected sleeper cabins.
Cars can be taken on the train at the car terminals only, and the vehicle is booked together with the ticket.
Skis travel free in the ski compartment. A bistro on board sells drinks and snacks.
There is a reduced fare for children who have their own seat or bed.