The Haard-Bahn (RE 42) operated at an interval of about half an hour after RE 2 on the section between Münster and Essen. This differed only by an additional stop in Recklinghausen Süd, which RE 2 stops at only in the off-peak.
On 11 December 2016, the Haard-Bahn was renamed the Niers-Haard-Express (RE 42) and extended to Duisburg, Krefeld and Mönchengladbach. Since December 2019, the additional trains in the peak hour between Haltern am See and Essen have been replaced by a service every 30 minutes between Münster and Essen.
^"Rhein-Haard-Express". NRW rail archive (in German). André Joost. Retrieved 10 April 2016.