The Cologne–Aachen high-speed line is the German part of the Trans-European transport networks project high-speed line Paris–Brussels–Cologne. It is not a newly built railway line, but a project to upgrade the existing railway line which was opened in 1841 by the Rhenish Railway Company. When it was continued into Belgium in 1843, it became the world’s first international railway line.
The line inside Germany has a length of about 70 kilometres (43 mi). The first 40 km (25 mi) from Cologne to Düren have been rebuilt. Since 2002 the line allows for speeds up to 250 km/h (155 mph). Separate tracks have been built parallel to the high-speed tracks for local S-Bahn traffic.
The remaining line from Düren to Aachen allows speeds up to 160 km/h (100 mph) with some slower sections. Upgrades of Düren–Aachen are planned for the near future. In Belgium, the high-speed line is continued as HSL 3.
Regional-Express services on the line are RE 1 (NRW-Express) and RE 9 (Rhein-Sieg-Express) with push-pull trains with six double-decker carriages. Long-distance trains are operated by Thalys between Paris and Cologne (six pairs of trains each day), three pairs of ICE 3M trains daily between Frankfurt and Brussels Monday to Saturday and a morning ICE 2 between Aachen and Berlin.
