The Düsseldorf–Solingen railway is a railway in the German state of North Rhine-Westphalia. It is a 19 kilometre line, entirely double track and electrified with overhead line. It is now used by the S 1 of the Rhine-Ruhr S-Bahn and Regional Express service RE47, operated by Regiobahn.

Line S1 is a S-Bahn line on the Rhine-Ruhr network. It is operated by DB Regio. It runs from Dortmund via Bochum and Essen to Duisburg. From there it travels south to Düsseldorf and Hilden before continuing to Solingen. It is operated on weekdays at 15-minute intervals between Dortmund Hbf and Essen Hbf, at 20-minute intervals between Düsseldorf Hbf and Solingen and at 30-minute intervals between Düsseldorf and Essen, using coupled sets of class 422 four-car electrical multiple units.