Hi Phil,
for using the train in D the following tipps:
- it is not possible to travel in the ICE with the bike!
- for using the IC you have to reserve the place for the bike in advance
- in other trans (RE, RB) you can take your bike with you. But there are different rules depeding on the region. I think it is possible in Berlin/Brandenburg and in Saxony. You have to buy a ticket for the bike too.