Labeled as the project of the century for the German metropolitan region, the Rhine-Ruhr express (RRX) will help alleviate the continuously worsening transportation issues along the Rhine and Ruhr from 2018. The municipalities involved in the new RRX rail transport concept commissioned Siemens to supply 82 electric multiple units, type Desiro HC, and to provide maintenance services for a period of 32 years. With a total volume of more than 1.7 billion euros, this is the largest regional rail service order in Germany so far for Siemens.

The region is one of the largest conurbations in Europe, with a population of approximately ten million and numerous transit routes. On the main section between Cologne and Dortmund in particular, mobility has been heavily restricted for years now by overstretched public transport networks and train connections. Through a targeted extension of the railway network and the shift of traffic from road to rail this enables, the RRX is expected to replace roughly 31,000 individual car trips every working day. The first RRX trains began operating in December. Commercial operation will begin on Line RE 11 that connects Düsseldorf, Essen, Dortmund, Hamm, Paderborn and Kassel. During rush hours the eventual target is one train every 15 minutes.