In the summer of 2001, DB Reise&Touristik abandoned InterRegio line 22, which ran from Frankfurt on the Ruhr–Sieg railway to Düsseldorf. The RE 16 service was established to replace it from the timetable change of 10 June 2001 by the transport association of the Rhine-Ruhr, Ruhr-Lippe and Westfalen-Süd. The newly created service ran initially via Siegen to Au ; this branch was taken over in December 2002 by the RB 95 service operated by Deutsche Bahn and operated since December 2004 under the brand name of DreiLänderBahn. In 2004, the operations of the RE 16 was tendered together with the RB 40, RB 56 and RB 91 services as the Ruhr-Sieg network. The tender was won by Abellio Rail and the operations of the tendered lines was awarded for twelve years from 9 December 2007. Since the commencement of Abellio services, Welschen Ennest has been added as a stop. As a result of the reductions in regionalisation funds, a change to weekend services was implemented at the 2007/2008 timetable change: as well as the normal RB 91 services, RE 16 services stop every 2 hours either at Meggen or Kirchhundem and at either Littfeld or Eichen from 4 pm or 5 pm to 8 pm on Saturdays and all day to 8 pm on Sundays. Because of this scheme, these four stations are served more often on Saturdays than on other days. Moreover, RE 16 services in the weekday peak towards Essen serve all stations between Siegen and Hagen. In the evening weekday peak RE 16 services from Essen serve all stations between Hagen and Siegen.
Route
The Ruhr-Sieg-Express runs daily every hour and utilises four railway lines built by the Bergisch-Märkische Railway Company:
the Ruhr line from Essen to Witten, using the long-distance tracks, which is also used by regional and long-distance trains,
A special feature of the service is the coupling and uncoupling of trains at Iserlohn-Letmathe. The trains from Iserlohn and Siegen are coupled in Iserlohn-Letmathe and run together via Hagen, Witten and Bochum to Essen. In the opposite direction the trains run coupled to Iserlohn-Letmathe, where they are separated with one section running to Siegen and the other to Iserlohn. Even the trains that run from/to Iserlohn, now carry the designation of RE 16, the former Iserlohner Bahn service now no longer exists as a separate service. The service to Siegen is usually made up of a three-part Stadler FLIRT set and the service to Iserlohn is usually made up of a two-part FLIRT set. On weekends the service to Iserlohn-Letmathe is operated as a three-part set, with a one or two part FLIRT continuing to Siegen and the rest going to Iserlohn.
Future
There are plans, with the start-up of the Rhine-Ruhr Express network planned for 2020, for the Ruhr-Sieg-Express and the Ruhr-Lenne-Bahn services to run between Essen and Bochum on the S-Bahn route via Wattenscheid-Höntrop instead of on the main line via Wattenscheid. The Ruhr-Lenne-Bahn would then run via Essen-Steele rather than Essen-Kray Süd.
NRW regular interval timetable
The Ruhr-Sieg-Express is operated under the integrated regular-interval timetable of North Rhine-Westphalia, called NRW-Takt, under which trains arrive at major interchange stations at roughly the same time in order to facilitate transfers. To supplement services in parallel with the Ruhr-Sieg-Express, two Regionalbahn services are operated, the Ruhr-Lenne-Bahn between Essen and Hagen and the Ruhr-Sieg-Bahn between Hagen and Siegen/Iserlohn. Due to the different number of intermediate stops for the different services, the combined services only provides stops at stations served by the express trains at approximately 30-minute intervals. In Siegen, the Ruhr-Sieg-Express has regular-interval connections with the Rhein-Sieg-Express towards Cologne, the Sieg-Dill-Bahn to Au and Dillenburg, as well as the Main-Sieg-Express to Gießen, continuing every two hours to Frankfurt. There are other connections in Iserlohn to the Ardey-Bahn to Dortmund and in Finnentrop to the Biggesee-Express to Olpe. In Iserlohn-Letmathe, it is a possible to change from services from Siegen to services to Iserlohn and vice versa each hour. Coming from Siegen/Iserlohn on the RE 16, it is possible to change in Hagen to the Volmetal-Bahn to Dortmund and Lüdenscheid, the Maas-Wupper-Express to Hamm and Venlo, the Sauerland-Express to Warburg and long distance services to Bremen/Hamburg and Hannover/Leipzig.
Rollingstock
In the early days of the Ruhr-Sieg-Express it was mainly operated with class 425electric multiple units, but later the rollingstock used varied considerably. So sometimes two class 426 EMUs were coupled, sometimes a class 425 and a class 426 set were coupled and sometimes singled sets were operated. Occasionally a triple set of class 426 was operated, which sometimes caused problems. In the last weeks before the change of operator, this often occurred, as the class 425 sets were no longer used. The use of both classes ended at the timetable change on 9 December 2007, when Abellio Rail NRW took over operations on the line with two-and three-part Stadler FLIRT EMUs. The contract with Abellio runs until December 2019.
