 Regional Express (RE) line 9 has existed since the introduction of the integrated timetable (, ITF) in North Rhine-Westphalia in 1998.Previously one train ran each day over the line to Mönchengladbach from Gießen to Kaldenkirchen.From 1998 the train service ran on the route from Krefeld via Neuss, Cologne, Siegburg and Siegen to Gießen.