Planning Between 1970 and 1983, more than 20 above ground options for section 1, to which the tunnel belongs, were considered. Under planning procedures introduced in 1983, five main above or underground options in the area Rastatt with different design speeds were examined. The initially planned route of the new line through
Durmersheim,
Bietigheim and
Ötigheim was fought intensely by local residents. Under political pressure, the new route was eventually moved to follow the already planned deviation of
federal highway 36. According to
Deutsche Bahn (DB), this transfer was possible at no additional cost, taking into account the need to resolve local issues if the previously considered route was chosen. According to DB, the selected tunnel solution is more economical, has greater capacity, would allow more efficient operations and would allow shorter journey times. As a result, the regional planning process was launched in July 1986 with the proposed route following the proposed new federal highway closely and then passing through a tunnel. In the middle of 1987, Deutsche Bundesbahn intended to initiate the planning approval process in late 1987. In 2002, the tunnel's planned length was . The northern and southern portals had been moved to the north. In mid-2010, the length of the tunnel was quoted as . In early 2009, it was intended to revise the planning for the Rastatt Tunnel, which was now over ten years old and to begin construction in early 2011. Both would be financed from funds from the economic stimulus package II. Because of the high financial requirements and the long duration of the project, it was later separated from the stimulus package. In 2011, Deutsche Bahn proposed an amendment to the plan, with among other things, the longitudinal spacing of the cross tunnels reduced from and special construction methods in the portal area to deal with
tunnel boom. The amendment was approved in November 2012. According to a media report the amendments to the plan were necessary because of new safety regulations (as of February 2012). On 24 August 2012, the
Federal Ministry of Transport, Building and Urban Development concluded a financing agreement on the northernmost section of the Rhine Valley Railway. It includes a northern section of line, which includes the Rastatt Tunnel. The section is designed for operations at up to . Tendering and contracting were to run from May 2013 to August 2014.
Construction During 2001, the construction interval was forecast to take around six years to complete. On 7 April 2011, fresh exploratory drilling for the tunnel began in the district of Niederbühl. Another exploration program began between Ötigheim and Rastatt Süd on 9 May 2012. Three rigs were due to drive 40 holes to depths of up to by October 2012. Work on the ramp at the northern tunnel portal was tendered in March 2013. This was to allow construction work to commence between Basheide junction and Rastatt Süd. The work was expected to be completed by 2015. At the end of 2013, work began on the construction of the northern groundwater basin. As part of works worth about €13 million, a and up to excavation pit was established and approximately of material and of sheet piles were installed. The work was expected to be completed by October 2014 (as of late 2013). It was expected that the construction of the actual groundwater basin would begin in early 2015, By the end of March 2014, the earthworks for the northern groundwater basin has been completed. Starting in July 2014, sheet
piles were driven into the ground in preparation of further construction activity commencing. The contract for construction of the shell of the tunnel was awarded to
Arbeitsgemeinschaft Tunnel Rastatt ("Rastatt tunnel construction community"), a company founded specifically to undertake this project. The technical leadership was taken by
Ed. Züblin AG and the commercial leadership by
Hochtief AG. Due to the
geological and
hydrological environment of the tunnel, a large part of it is being driven by two
tunnel boring machines (TBMs), which travelled its length along the north-to-south alignment. Some of its length was tunnelled through ground that has been stabilised by a combination of
ground freezing (using either
brine or
liquid nitrogen) and
concrete injections. According to an updated schedule of June 2015, the beginning of the tunnel drive had been delayed by three months to the spring of 2016 as the first parts of the tunneling machine would be delivered at the end of 2015. The completion of the tunnel shell is still scheduled for July 2018. From the end of 2015, the first parts of the TBM were delivered at the north portal at
Ötigheim and were assembled there in preparation for driving the eastern tube from early February. The first TBM was symbolically launched on 8 December 2015. It was expected to start driving the eastern tunnel at the end of May 2016. A stretch of earthworks with a length of about was completed to the north of the tunnel at the end of 2006 and it has been extended at Ötigheim since early 2013. In April 2016, the construction of the tunnel's connections were put to tender.
August 2017 collapse Sensors at the tunnel construction site at Niederbühl reported a lowering of the track on the existing line above the tunnel on 12 August 2017 at about 11:00. Signals along the line automatically set to
danger, stopping all train traffic. The track had subsided by half a metre () over a section of track that was about long. In this area, the tunnel is covered by of material. The bore was intended to run over a length of through completely frozen material, representing an innovation in the use of TBMs. As a result of a water spill, the tunnel was not accessible at first. Following work to stabilise the area,
DB Netze commenced work to plan the line's reopening and resumption of construction. By 22 August, a closure of the line until 7 October was expected. During the closure, an emergency bus service was established between Rastatt and Baden-Baden. This service was operated at six-minute intervals from 14 August; passengers were informed to expect extensions of travel time of at least an hour. The residents of four neighbouring houses were asked to leave them on 13 August. The
Netzwerk Europäischer Eisenbahnen estimated the revenue loss for freight companies at €12 million per week. Even with all the large-scale diversions, insufficient capacities would be available, since several detours were also blocked. By 15 August 2017, according to DB information, work was already being carried out on the restoration of the line, although the stabilisation of the tunnel still had remaining queries to address. It was anticipated that a section of the eastern tube would be filled with concrete in order to stabilise the ground, allowing the re-opening of the railway line as soon as possible. This process necessitated the abandoning of the existing TBM, which was valued at €18 million, as it would remain in the ground. At the time, the means of addressing the damaged eastern bore of the tunnel, and the project's overall completion, were unclear. On 2 October 2017, the old rail line, which had been rendered unusable for nearly two months due to damage sustained from the collapse, was reopened. DB had constructed a large concrete slab, being 120 metres in length, 15 metres in width and one-metre deep, to effectively act as a bridge for the old ground level railway over the eastern bore; a second slab was built over the western bore as well to avoid any possibility of reoccurrence. Rail freight operators had sought compensation for the impact to their businesses caused by the collapse and subsequent disruption, some companies publicly criticised DB specifically for failing to provide a temporary low-speed diversionary line around the tunnel site and generally for its lack of disaster mitigation planning. By early October 2017, proposals had been mooted for the recovery of the TBM's remains, which had been intentionally entombed in concrete, by digging it out of the ground; however, there was no immediate plan of how to resume construction of the eastern bore. By July 2018, limited activity was happening on the eastern bore, including the creation of an opening to act as an emergency escape and to aid logistics during further construction work. As agreed,
Arbeitsgemeinschaft Tunnel Rastatt would continue with work to finish the remaining 200 metres of the undamaged western bore, while DB shall reposition a 700-metre section of the old line to follow the course of the completed western bore on the surface, putting it clear of the eastern bore's construction site. After the repositioning, which was anticipated by 2021, the remaining portion of the eastern bore would be excavated using an open 'cut-and-cover' method after inserting concrete walls to the required depth. In August 2025, Deutsche Bahn announced it had completed the civil works for the tunnel, having excavated around 52,000 m3 of earth. == Costs==