[6] In Buggingen, south of Freiburg, the freight bypass and the Rhine Valley Railway will meet up again and run in parallel to Schliengen.

Between Schliengen and Eimeldingen the new line runs through the Katzenberg Tunnel, which with a length of 9.4 kilometres is the largest single structure in this section.

According to the federal government, although the speeds could have been increased to 300 km/h (190 mph) on some disconnected sections, this would not have had significant travel time benefits.

[8] In the 20th century, there were demands for a new railway line to stimulate the central and southern Upper Rhine economically and to allow additional traffic to run.

[9] A study in 1964 for the executive board of Deutsche Bundesbahn proposed the straightening of the line—particularly in Rastatt and Offenburg—to achieve significant travel time savings.

[18] As part of the Stufe I (“level I”) of the BVWP 1980, the first work would have been a new double-track line between Rastatt and Offenburg to be built by 1990 for DM 960 million.

Stufe der ABS/NBS Karlsruhe – Offenburg – Basel ("level 1 of the Karlsruhe–Offenburg–Basel upgraded and new line") with an investment cost of DM 1,678 million.

It developed three groups of options that could be combined for the section between Freiburg and Basel: along the Rhine Valley Railway, along the autobahn and bypass routes.

Considerations of passenger traffic bypassing Freiburg with a route that was about 7.5 kilometers shorter and would serve the city with a station at the intersection with the Freiburg–Colmar railway at Hochdorf have since been discarded.

[17] In the second half of 1993, a continuous four-track upgrade of the Rhine Valley Railway was an element of the draft Federal Transport Infrastructure Plan 1992.

[15] In 1988, it was planned to leave the section between Offenburg and Basel as double track, but to upgrade it for maximum efficiency and a top speed of 200 km/h.

[32] When the Swiss parliament took the decision in 1991 to adopt the NRLA project, it also assumed that the line south of Offenburg would be rebuilt with four continuous tracks.

According to the previous assessment an upgrade of the existing line, including equipping it with CIR-ELKE (a now-superseded form of computerised operations and control of railways developed by Deutsche Bundesbahn in the 1990s) would only become necessary with the full utilisation of the new Alpine crossing.

[37] At the end of June 2000, DB Netz was studying the needs of for Offenburg-Niederschopfheim, Schliengen-Eilmeldingen and Haltingen Weil am Rhein sections.

[40] On 4 March 2013, the project advisory board unanimously selected the so-called Bürgertrasse ("citizens’ route") through the Markgräflerland as well as the implementation of additional measures to control noise on the freight train bypass of Freiburg.

[42] In 2009,[3] a project advisory board was established with representatives of the federal and the state department of transport, district administrators, local politicians and citizens' groups.

[41] After five years of discussion, the Projektbeirat Rheintalbahn (“Rhine Valley Railway Project Advisory Group”) held its tenth and final meeting on 26 June 2015.

[45] On 12 December 1987, work began on the construction of two additional tracks on the Rastatt–Offenburg section in Achern station in the presence of the then Chancellery Minister Wolfgang Schäuble.

[27] Earthworks, including the track base, were completed at the end of 2006 over a length of over 7.5 kilometres for the new line between Karlsruhe and Rastatt, which was built together with the parallel construction of a new section of federal highway 36.

It branches from the old Rhine Railway at the Bashaide block post near Durmersheim and runs to the approximate beginning of a future trough structure on the approach to the Rastatt Tunnel south of Ötigheim.

[49] After nine years of construction and the investment of approximately €260 million, the 20 km-long section between Rastatt Süd and Buhl went into operation at the timetable change on 12 December 2004.

[51] According to the federal government, the piece-by-piece upgrade of the Rhine Valley Railway will provide sufficient capacity for the growth of traffic on the line when it is needed.

[52] According to the Federal Ministry of Transport, progress favours the completion by 2022 of the upgrade to four tracks with the exception of the 40-kilometre section between Offenburg and Riegel/Kenzingen.

[53] A forecast for the Federal Transport Infrastructure Plan indicates that 38 pairs of trains in long-distance traffic will run on the Offenburg–Basel section each day.

[7] The German government expects the most heavily congested section of the Rhine Valley Railway to carry 335 trains per day in 2025.

[3] In December 2013, Deutsche Bahn announced its intention to call for tenders for a number of construction projects in the planning approval sections 9.0 to 9.3 for a total of around €200 million.

[54] The Federal Government considers the substantial completion of the project by 2030 is possible if two core requirements, the Offenburg Tunnel and the section next to Autobahn 5 around Freiburg, are omitted.

[35] On 24 August 2012, Federal Ministry of Transport, Construction and Urban Development and Deutsche Bahn completed a financial agreement providing €693 million for the most northerly section of the project.

[59] According to press reports, the additional cost of this option (compared to the route next to the current line as originally proposed) amounts to €300 million.

[61] A number of citizens' initiatives, which have combined as the Interessengemeinschaft Bahnprotest an Ober- und Hoch-Rhein (“community of interest of the railway protest of the Upper and High Rhine”; abbreviated IG BOHR), which have been referred to as Baden 21, presented an alternative approach; 172,000 signatures were collected in support of this.