S1 (Rhine-Ruhr S-Bahn) Services ran via Düsseldorf Airport Terminal station from 24 May 1998 to 28 May 2000. Services were extended from Düsseldorf to Solingen on 13 December 2009, replacing part of the former line S 7 service. S1 (Rhine-Ruhr S-Bahn) Line S1 is a S-Bahn line on the Rhine-Ruhr network. It is operated by DB Regio. It runs from Dortmund west over Essen to Duisburg. From there it travels south to Düsseldorf and Hilden before continuing to Solingen. It is operated at 20 minute intervals, using coupled sets of class 422 four-car electrical multiple units. Line S 1 runs over lines built
Rhine-Ruhr 20th century. Since the Middle Ages, Cologne, Dortmund and other cities were important regional trading cities, but during the 19th century the city of Düsseldorf grew to become the administrative center of the region and since 1945 its political capital. Today, the Rhine-Ruhr metropolitan region accounts for roughly 15% of the GDP of the German economy, which would place it as the 4th largest GDP of metropolitan area in the European Union and the 16th largest GDP in the world. Despite this size, the Rhine-Ruhr region as a whole often lacks international competitiveness because it lacks a unified presentation. Cities