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
S4 (Rhine-Ruhr S-Bahn) has been removed from the integrated transportation plan for North Rhine-Westphalia; a resubmission is possible from 2015. S4 (Rhine-Ruhr S-Bahn) Line S 4 is an S-Bahn of the Rhine-Ruhr S-Bahn, running from to the Dortmund suburb of Dortmund-Lütgendortmund. It is operated by DB Regio on behalf of Verkehrsverbund Rhein-Ruhr. It is operated at 20-minute intervals using class 422 four-car electrical multiple units. Line S 4 runs over several lines: S-Bahn services commenced between old Lütgendortmund station and Unna station on 3 June 1984. The section from Germania to old Lütgendortmund station was closed on 31 August 1987 and operations on