There currently are a variety of options to travel by night train from Innsbruck (Austria) to Bremen (Germany), taking between approximately 11 and 13 hours: Namely the UEX 1300, the UEX 1302, the UEX 1306 and the UEX 1308. These lines are operated by UEX.
UEX (Urlaubs-Express) operates seasonal night trains, including car-carrying trains (Autoreisezüge), from Germany to Austria and back.
Options range from seats and shared couchettes to private couchette compartments, sleeper compartments and connected sleeper cabins.
You can bring your car, but only between the car terminals, and you book the vehicle along with your ticket.
There is a free ski compartment. Drinks and snacks are available in the bistro on board.
Children with their own seat or bed pay a reduced fare.