The service between Berlin, Hamburg and Copenhagen is operated mainly by Deutsche Bahn's InterCity Express (ICE) trains, although a couple of services are InterCity trains. There is only one direct service between Berlin and Copenhagen each day in either direction, but plenty of connecting trains available from Hamburg for the final leg to/from Berlin. The route includes a train-ferry crossing between Rodby and Puttgarden. Passengers are able to leave the train once on-board the ferry to explore a variety of duty free shops, cafes, lounges, bathrooms etc.
Puttgarden is a village and harbour on the Danish island of Fehmarn. The harbour lies on an important route between Germany and Denmark for cars and to a lesser extent trains.