Reserving tandem and recumbent trike slots on trains in Europe.

I have spent some time recently investigating accompanied recumbent trike transport by train in Germany. Deutsche Bahn (DB) the main long-distance train operator in Germany does not carry these vehicles on their long-distance trains (Fernverkehr). It is possible though I suspect difficult to transport these on some regional and local trains ((Nahverkehr), but reservations are not possible. If one is unlucky and the train is full, that's it you wait for the next one, or the next but one, or…

I contacted all of the companies running long-distance trains in Germany and was overjoyed to receive a positive answer from ÖBB Austrian Railways. The company runs Nightjet sleeper and couchette trains across Europe. One can travel with tandem or trike on the following trains:

• NJ 466 Vienna - Linz - Zurich 
• NJ 467 Zurich - Linz - Vienna
• NJ 490 Vienna - Linz - Hanover - Hamburg
• NJ 491 Hamburg - Hanover - Linz - Vienna
• NJ 40420 Innsbruck - Munich - Hamburg
• NJ 40491 Hamburg - Munich - Innsbruck

"For recumbents, tandems or bicycle trailers, two spaces must be booked. These can only transported  in special luggage compartments." 
(My translation of an email from ÖBB in German.) 

It's not many train pairs but it is a start. It strikes me to charge for two slots is a more sensible solution than a blanket "NO!". I suspect many train operating companies have issues with bicycles.