Rätia is a EuroCity train service that linked Hamburg in Germany with Chur in Switzerland via Dortmund, Cologne, Mannheim, Basel and Zurich, following the river Rhine for a significant part of its journey.

From the north, the service starts at Hamburg-Altona, and runs over the Altona link line through to Dammtor and Hamburg Hauptbahnhof.

From Cologne the train heads south again, sticking close to the Rhine on the west bank, via Bonn, Koblenz, and Mainz.

At Zurich, the train changes direction again, and for the remainder of the journey it takes on the stopping pattern of an InterRegio service.

After a stop at the junction station of Sargans, the train heads south towards Landquart and rejoins the Rhine, crossing it, then running parallel to it, as well as the narrow-gauge Rhätische Bahn railway until its final destination of Chur.

Two years later, service 8/9 was truncated entirely to Zurich, while 6/7 was redirected to Interlaken Ost, with Chur now served by ICEs from Hamburg, running via Hanover rather than the Rhine.