[15] As part of the South Hesse Integrated Planning (Integrierten Planung Südhessen), operational investigations were carried out to increase capacity between Frankfurt and Mannheim from 1997 to 1999.

The original approval documents, which provided for a connection to Mannheim, were withdrawn, and the regional planning procedure was stopped at the end of February 2000.

[19] In March 2000, Deutsche Bahn CEO Hartmut Mehdorn, announced that after the completion of the new line, no fewer trains than at present would stop at Mannheim Hauptbahnhof.

[21] Deutsche Bahn presented two possible routes, including one running through Mannheim Hauptbahnhof, to the Karlsruhe regional administration as part of a first scoping stage on 30 October 2000.

On 18 April 2002, representatives of Deutsche Bahn confirmed that the company was continuing with its application for the implementation of the regional planning procedure (Raumordnungsverfahren).

[34] A working group on the Baden-Württemberg section of new line, initiated by minister president Günther Oettinger, was due to commence operations at the beginning of September 2007.

[39] In December 2008, Deutsche Bahn AG initiated the planning approval for a 13 km-long section between Frankfurt Stadion station and the municipal limits of Mörfelden and Erzhausen.

[53] On 21 July 2014, the commissioned company, Intraplan, presented the first results of the Korridorstudie Mittelrhein (Middle Rhine corridor study).

The full opinion was originally expected to be presented in autumn 2014, followed by a public consultation phase before a decision was taken on the Federal Transport Infrastructure Plan 2030 (Bundesverkehrswegeplan 2030) by mid-2015.

[56] The "NBS Rhein/Main – Rhein/Neckar" project was listed in the "draft proposals" in the Federal Transport Infrastructure Plan 2015 of 5 May 2014 on the "(Frankfurt am Main Stadion –) Zeppelinheim – Mannheim-Waldhof" route with a top speed of 300 km/h (186 mph).

[58] Deutsche Bahn and the ministries of transport of Hesse and Baden-Württemberg presented a roadmap for future planning at the Technical University of Darmstadt on 30 September 2016.

[62] In addition to the concept favoured by Deutsche Bahn of a double-track new line used during the day by long-distance passenger trains and at night by freight trains, three other concepts were discussed: In May 2018, Deutsche Bahn continued to favour a new double-track line that would be used during the day for long-distance traffic and at night for freight traffic.

For the Lorsch–Mannheim section (PFA 5 and 6), the alignment was still pending with the selection of the route expected to take place at the beginning of 2019 and the planning approval documents to be submitted in 2022.

For options I and II, soundproofing measures of just 6.3 km in length were recommended as part of a noise analysis; the number of citizens affected was stated in the regional planning procedure at 65,940.

[69] At a press conference on 2 February 2007 in Darmstadt, the DB CEO Hartmut Mehdorn, the Hessian Minister of Economics Alois Rhiel, Darmstadt Lord Mayor Walter Hoffmann and district council leaders Alfred Jakoubek (Darmstadt-Dieburg) and Matthias Wilkes (Bergstraße) for the Hessian part of the route called for the so-called consensus or bundled route.

[70] This starts after the existing underground connection with the Cologne-Frankfurt high-speed railway south of the Frankfurter Kreuz and runs on the eastern side parallel to the A5.

[71] The Bund für Umwelt und Naturschutz Deutschland criticised the route for touching several flora and fauna habitats and bird reserves.

[72] In an interview on 15 September 2006, Oliver Kraft, DB Netz's board member responsible for investments, threatened to suspend planning at the end of 2006 if Darmstadt and Mannheim continued to insist on all trains stopping in these cities.

[73] In April 2008, district administrator Matthias Wilkes of Bergstraße presented a feasibility study, according to which a tunnel through the Hessian Ried was cheaper than the ground-level route favoured by DB.

This line would branch off between Weiterstadt-Riedbahn and the Täubcheshöhle nature reserve towards the Hauptbahnhof and reconnect in the area of Kelley Barracks (near Pfungstadt) south of the Darmstadt interchange.

The 13 km-long[33] connection from Darmstadt Hauptbahnhof was considered structurally complicated, as several major roads and land formerly used by the US Army and areas protected under Natura 2000 have to be crossed.

[33] At the end of March 2009, the mayor of Darmstadt surprisingly announced that he could no longer pursue the bypass option, which would cost up to €112 million, and instead opted for a long-distance station on the new line.

Since only the connection to Darmstadt Hauptbahnhof is part of the Federal Transport Infrastructure Plan, such a long-distance station would have to be financed from Deutsche Bahn's own funds.

[83] At the end of August 2010, the city's Transport and Environment Committees drew up a proposal to connect Darmstadt with the new line only to the north, which would support a shuttle service to Frankfurt Airport.

[85] A "North connection of Darmstadt Hbf to the new line" was included in the "draft of project proposals" for the Federal Transport Infrastructure Plan 2015 of 5 May 2014.

The Middle Rhine Corridor Study (Korridorstudie Mittelrhein), which was submitted in March 2015, proposed various options for connecting Darmstadt Hauptbahnhof.

[87] At the beginning of January 2016, talks about the Darmstadt connection were well advanced according to the Hessian Minister of Transport Tarek Al-Wazir, although the exact routing had not been determined.

Deutsche Bahn sees an advantage of the bypass in that it would largely avoid noise pollution caused by freight traffic in the urban area.

In conjunction with the planned Stuttgart–Augsburg new and upgraded railway the travel time for long-distance traffic between Frankfurt am Main and Munich would be reduced from today's minimum of 31⁄2 to as little as 21⁄2 hours in the future.

The main disadvantage of this option lies in the bypass of Mannheim Hauptbahnhof, a long-distance traffic node, by some of the trains running between Stuttgart and Frankfurt.