The term Riedbahn was originally used for the Darmstadt–Worms railway and the two lines share the central section between Groß-Gerau and Biblis.

[2] On 29 May 1869, the line from Darmstadt via Riedstadt-Goddelau and Biblis to Rosengarten station, on the opposite side of the Rhine from Worms, was opened by the Prime Minister of the Grand Duchy of Hesse, Reinhard Carl Friedrich von Dalwigk.

Until the opening of the 9.5-kilometre (6 mi) long Western Entrance to the Riedbahn (westlichen Einführung der Riedbahn, WER) to Mannheim Hauptbahnhof in 1985, trains from Frankfurt came from the south to reach Mannheim and had to reverse to continue south towards Heidelberg or Karlsruhe on the Rhine Valley line.

Some TGV and Intercity-Express (ICE) services continue to use the eastern branch of the Ried Railway to cross the Rhine without reversal.

Almost all regional trains run on the new western approach; Mannheim-Käfertal station is currently operated by one Regionalbahn service each day.

[4] In its successor, the Co-ordinated Investment Program for Federal Transport Infrastructure (Koordinierten Investitionsprogramm für die Bundesverkehrswege) of 1977, the track was included as one of six development projects.

[5] The development project was also included in the Federal Transport Infrastructure Plan (Koordinierten Investitionsprogramm für die Bundesverkehrswege) of 1980.

[6] The Federal Transport Infrastructure Plan of 1985 included the first stage of the route, which was essentially the new approach to Mannheim Hauptbahnhof, as part of the most urgently needed works.

[7] At the timetable change in May 1998, the maximum speed limit on a 15 km length of the southern section[12] was raised to 200 km/h.

Most freight traffic runs over the parallel Main Neckar line because of its better connection to the Mannheim marshalling yard.

In addition to the regional services of the Rhein-Main-Verkehrsverbund and the Verkehrsverbund Rhein-Neckar, three Intercity-Express lines run on the Ried Railway, connecting southern Germany with Berlin, Hamburg and Cologne/Dortmund.

Deutsche Bahn originally proposed to build a bypass of the Mannheim Hauptbahnhof (the most important rail junction in southwestern Germany, although it is not a Category 1 station like Karlsruhe Hbf), but dropped this plan for the time being in 2006 due to strong community and political opposition.

[17][18] The second track of the eastern branch of the Ried Railway in Mannheim is to be reactivated in 2015 and the line will be served by S-Bahn services, according to the Baden-Württemberg Ministry of Environment and Transport.