The Haard-Bahn (RB 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, was Haard-Bahn was renamed the Niers-Haard-Express (RE 42) and extended to Duisburg, Krefeld and Mönchengladbach. The additional trains in the peak hour between Essen and Haltern also bear this name, although this is not geographically correct as the Niers flows through Mönchengladbach. The Haard is a ridge in the Haltern Hills.

The Rhein-Haard-Express operated from 1998 to 2002 as the Haard-Express only between Münster and Essen. From the timetable change in December 2002, it ran via Duisburg to Mönchengladbach, taking over the Duisburg–Mönchengladbach section from the Rhein-Emscher-Express (RE 3), which ran to Düsseldorf instead.

With the timetable change on 12 December 2010 there was another exchange of routes with the Duisburg–Mönchengladbach section operated by the Rhein-Hellweg-Express (RE 11), which now runs hourly between Hamm and Mönchengladbach.

In return the Rhein-Haard-Express took over the Duisburg–Düsseldorf section and also operates as an hourly service. In this section, there are normally five Regional-Express services per hour (RE 1, 2, 3, 5 and 6), and four Regional-Express trains per hour on the Essen-Duisburg section (RE 1, 2, 6 and 11).

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