The Rhein-Weser-Express (RE 6) is a Regional-Express service route in the German state of North Rhine-Westphalia, connecting some of the most important cities in Westphalia (among others Minden, Bielefeld and Hamm) with the Ruhr (especially Dortmund, Bochum, Essen, Duisburg, Düsseldorf, Neuss and Cologne). Cologne, Neuss, Düsseldorf and Duisburg lie on the Rhine while Minden lies on the Weser. Until the timetable change in December 2016, this services was called the Westfalen-Express and ended in Düsseldorf Hauptbahnhof. The line is part of the Rhine-Ruhr Express (RRX) network and is operated by National Express. History Until the timetable revision of 2002, the NRW-Express (RE 1) operated with five, and sometimes up to eight, double-deck carriages from Aachen to Bielefeld. In 2002 services were extended to Minden and at the same time the service was split into two routes. The Westfalen-Express was established, taking over the Hamm–Bielefeld–Minden section and extending to Düsseldorf. This change was intended in particular to improve the timeliness of the entire service. A service called line RE 6a was put into operation as a pre-operation for the Rhein-Ruhr-Express on 13 December 2015. For the first time, Düsseldorf Hauptbahnhof was regularly connected with Cologne/Bonn Airport, serving on the way Neuss Hauptbahnhof, Dormagen, Cologne Hauptbahnhof, with some services also stopping in Köln Messe/Deutz in the peak. This interim line was scheduled to be operated with double sets of class 425 EMUs. The reason for the temporary separation of RE 6 and RE 6a was the lack of emergency brake connections between the double-deck cars used on line RE 6 (Minden–Düsseldorf), which were not allowed to run through the Cologne Airport loop. At the change of timetable in December 2016, the rolling stock was replaced by retrofitted double-decker trains, the RE 6 was extended to Cologne/Bonn Airport and the line RE 6a service was discontinued. The RE 6 services has been named the Rhein-Weser-Express since its extension. Since the timetable change in December 2019, the Rhein-Weser-Express has been operated by National Express with Siemens Desiro HC EMUs. Route The Rhein-Weser-Express runs on a total of four railway lines: all of the Hamm–Minden line (which carries all forms of regional and long-distance passenger services and freight traffic over a four-track route.) all of the Dortmund–Hamm (which carries all forms of regional and long-distance passenger services) all of the Dortmund-Duisburg line (on the long-distance tracks, which carry all regional and long-distance services), the Cologne–Duisburg