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
Ruhr breaks between the individual city boroughs. Thus the Ruhr is described as a polycentric urban area, which shares a similar history of urban and economic development. Because of its history, the Ruhr is structured differently from monocentric urban regions such as Berlin and London, which developed through the rapid merger of smaller towns and villages with a growing central city. Instead, the individual city boroughs and urban districts of the Ruhr grew independently of one another during the Industrial Revolution. The population density of the central Ruhr is about 2,100 inhabitants per square kilometre (about 5,400 per square mile)—low compared