Taking luggage on the trains
If you can carry your bags in one go, then you can take along your luggage yourself. You can put your luggage in the designated space over the seats, between the backrests, or at the end of the coach. Keep an eye on your luggage at all times. Theft mostly occurs at larger crowded stations.
If you have more luggage than you can carry, or if you want to travel more comfortably, then it's recommended to use a luggage service.
Storing luggage at the station
All larger rail stations have lockers you can rent for 24 hours. Many of them also have a staffed left luggage office where you can store your luggage for any amount of time.
You can take along your bike in most trains. In some trains it's not possible. Some trains require a reservation. The timetable shows whether these exceptions apply. You need to buy a bike ticket. Packed folding bikes are free to take along.