The Blauer Enzian is a named express train service that currently runs between Frankfurt in Germany and Klagenfurt in Austria.

It ceased to be a named train in 2002, but was revived in 2017 as an ÖBB EuroCity from Frankfurt to Klagenfurt, with through coaches onwards to Zagreb in Croatia.

In 1951, the West German Deutsche Bundesbahn announced the introduction of the Blauer Enzian as part of the then-new Fernzug network.

[4] The route of the F 55/56 express train, from Hamburg-Altona station to München Hauptbahnhof, included that of the first German high-speed railway, built later.

These cars were hauled by an ordinary express train south of Munich, still called Blauer Enzian and first-class-only, but not designated as a TEE.

[8] In 1970, the full Trans Europ Express route renumbered TEE 80/81 was extended to Austria and the train was split in Rosenheim, with one part going to Klagenfurt and the other to Zell am See via Kufstein and Wörgl.

[9] Although the Zell am See service had disappointing passenger numbers, it remained[6] in the timetable to serve the expected tourists related to the 1972 Summer Olympics.

On 31 May 1987, the Blauer Enzian became part of the newly introduced international EuroCity network,[11] with train number EC20 northbound and EC21 southbound[14] (later renumbered EC12/13).