Mülheim (Ruhr) Hauptbahnhof Mülheim (Ruhr) Hauptbahnhof Mülheim (Ruhr) Hauptbahnhof is a railway station for the city of Mülheim in the German state of North Rhine-Westphalia. It was renamed as a Hauptbahnhof in 1974 at the time of the rebuilding of the Dortmund–Duisburg line as part of the establishment of the Rhine-Ruhr S-Bahn. It is classified by Deutsche Bahn as a category 3 station. The original station is unusual in that it was built as two adjoining stations by the two main private railways buildings lines in the Ruhr area, the Rhenish Railway Company ("Rheinische Eisenbahn-Gesellschaft", "RhE") and the Bergisch-Märkische Railway Company ("Bergisch-Märkische Eisenbahn
S-train tunnel under the central station and the city centre. The high number of large cities in the Ruhr area promotes a polycentric network connecting all cities and suburbs. The "S-Bahn Rhein-Ruhr", as it is called, features few tunnels, and its routes are longer than those of other networks. The Ruhr S-Bahn is the only S-Bahn network to be run by more than one corporation in Germany, and the Salzburg S-Bahn holds a similar distinction in Austria. Most Swiss S-Bahn systems are multi-corporation networks, however. Most German S-Bahn networks have a unique ticket system, separated from the "Deutsche Bahn" rates, instead