I wrote some stuff about train travelling with a bass through Germany (and from Hamburg to Copenhagen to BASS2012).
It is the officially the inofficial guide to train travel to BASS2012, since I always stayed in contact with the BASS2012 organization.
Traveling with a bass by train is risky but generally possible. The main problem is the lack of space (specially in ICE trains) and you cannot make reservations for the bass in any train.
If you can go there by car, ship or plane this should generally be preferred.
You can visit my hints at http://spix.homeip.net/~jgspix/bass-traintravel/
in german and english language.
Since this is my old server at home, it might crash while I'm on vacation. So if you need the information, better download the files.