The Cologne-Duisburg line has been continually modernised as traffic has grown and it has been electrified along its entire length.
Number of tracks
The number of tracks on the line varies between three and eight. In the section of line between Cologne and Cologne-Mülheim there are six tracks, two towards Düsseldorf and Duisburg, two towards Gruiten and Wuppertal, and two S-Bahn tracks. Between Cologne-Mülheim and Langenfeld, there are two long-distance tracks and sections of the S-Bahn are only single track sections. North of Langenfeld, there are again two tracks. From Düsseldorf-Oberbilk station north there are two additional tracks to the right and left of the S-Bahn to Düsseldorf; together with the local lines in this section there are eight rail tracks. From Düsseldorf to Düsseldorf-Derendorf station the line also has up to eight single tracks, including up to two freight lines. There are six tracks past the S-Bahn branch to Düsseldorf Airport Terminal station to Düsseldorf-Unterrath Karthäuser Weg junction where the S-Bahn and two long distance-tracks merge at grade on the approach to Düsseldorf Airport station. The station itself has four platform tracks, plus two through tracks. After the airport station, the route continues as a four track line, with the platform tracks at S-Bahn stations passed by Regional-Express trains at up to 140 km/h. Immediately south of Duisburg-Großenbaum station two separate S-Bahn tracks recommence in addition to four mainline tracks, a total of six tracks. North of Duisburg-Buchholz the line becomes five tracks with two mainline tracks, two S-Bahn tracks and one freight track. North of Duisburg Hauptbahnhof lines connect to the CME’s line to Oberhausen and Dortmund, and more importantly for today's passengers, the Ruhr route to the east via Essen to Dortmund of the former Bergisch-Märkische Railway Company.
Technology
To shorten the travel time on the long-distance trains from Cologne via Duisburg to Dortmund, the mainline was upgraded in the 1980s to enable trains to run at 200 km/h and, with the exception of the area of Düsseldorf station, equipped with the GermanLinienzugbeeinflussungtrain protection system. This makes it possible to operate trains between Cologne and Dortmund via Duisburg in the same time as it takes on the shorter but more tortuous route via Wuppertal and Hagen. This makes it possible to provide connections between two long-distance routes across platforms at Cologne and Dortmund.
Train services
Services operating across the total length of the line are three ICE services, two IC services and two Regional-Express services, the RE 1 NRW-Express and the RE 5 Rhein-Express. Between Düsseldorf and Duisburg additional services operating are the RE 2 Rhein-Haard-Express, the RE 3 Rhein-Emscher-Express, the RE 6 Rhein-Weser-Express, the RE 11 Rhein-Hellweg-Express and the RE 19 Rhein-IJssel-Express. It is planned to replace the Regional Express services on the line by faster services, known as Rhine-Ruhr Express, which will require additional track.