If you have an Interrail Pass, night trains are a convenient way to save time and money. You must reserve and pay for your sleeping accommodation in advance, but as a Pass holder, you only pay the reservation fee—not the full ticket price. Reservation costs vary by train and comfort level.
While reservations add to your costs, you save on hotel or hostel expenses. Most night trains offer both beds and seats; seats are usually cheap or sometimes free, but availability is limited, so book early.
If your night train departs one day and arrives the next without a train change after midnight, you use only one travel day (the departure day). If you change trains after midnight, you use two travel days. Note: You can't use your Pass for a night train on your last travel day, as validity ends at 23:59.
Find more details about night trains, sleeping options, and reservation costs here. With some planning, you can travel comfortably and affordably by night train.
Also, read Rail Planner App – Editing journeys & Night trains for guidance on adding night trains to your trip.