Originally Posted by
Machka
In Switzerland, you will need to book the bicycle, and it will be a bit expensive.
Fortunately, this is not always true. Bookings are only required on the ICN trains (the fast city-to-city trains) from 21 March to 31 October. Almost all other trains accept bikes (mostly self loading) without a booking. Costs vary, but it's never more than CHF 18.- for a day card. Otherwise, for short journeys you can just buy a regular ticket for the bike.
More information is here.