Line S 5 is a S-Bahn line in the Rhine-Ruhr network. It is operated by DB Regio. It runs from Dortmund Hbf via Witten Hbf to Hagen Hbf. There are current plans to expand the line by building five new stations. It is operated between Düsseldorf and Wuppertal-Oberbarmen at 30 minute intervals using class 422 electric multiple units.
Line S 5 runs over the Elberfeld–Dortmund railway opened by the Bergisch-Märkische Railway Company on 20 December 1848.
S-Bahn services commenced on the whole length of the route on 29 May 1994.
- Eisenbahnatlas Deutschland (German railway atlas) (2007/2008 ed.). Schweers + Wall. 2007. ISBN 978-3-89494-136-9.