Müllheim–Mulhouse railway

In 1865, there were the first petitions by some of the neighbouring communities to the Grand Duchy of Baden for the building of a railway from Müllheim to Mulhouse. The Baden government published an act on 30 March 1872 for "the creation of a railway from Müllheim to Neuenburg and possibly continuing to Mulhouse."^[5] Work began on the line in late 1876.^[5] The railway was opened in February 1878 to supply the area around Mulhouse with food and timber from the area around Müllheim.^[6]

The Neuenburg–Chalampé bridge over the Rhine was demolished on 12 October 1939 during the Second World War. Deutsche Reichsbahn rebuilt the bridge as a single track in 1940–1941. German troops destroyed it again during their retreat on 9 February 1945.^[7]

The branch line from Müllheim to Neuenburg am Rhein was electrified by May 1965.

From the summer of 1975 there were only four pairs of trains a day between Mulhouse and Müllheim^[8] Passenger services on the Müllheim–Neuenburg section were discontinued on 31 May 1980.^[8] However, the line remained open for freight traffic.

In October 1998, the Breisgau S-Bahn operated a special train with a Regio-Shuttle. Feasibility studies in the spring of 2004 showed that the line would have a favourable cost-benefit ratio.^[8] After a three-week trial operation, the opening ceremony was held for the resumption of passenger service on 27 August 2006. From 2006 to 2012, it was operated on certain Sundays and public holidays as a special event service. Since 9 December 2012, there are up to seven services daily between Baden and Alsace, with at least one pair of trains running directly to and from Freiburg Hauptbahnhof.^[9] Since then, a French X 73900 (called Baleine Bleue in French and Blauwal in German, meaning "blue whale") has been used.

Müllheim–Badenweiler railway

In 1894, the Müllheim–Badenweiler railway (Müllheim-Badenweiler Eisenbahn, MBE) was founded with a significant contribution from the railway construction and operating company, Vering & Waechter. Operations commenced as a steam-powered tramway on 15 February 1896. It was operated by Vering & Waechter until the German Railway Operating Company (Deutsche Eisenbahn-Betriebs-Gesellschaft, DEBG) took over the operational management in 1899. The steam trains were replaced on 7 April 1914 by electric vehicles, which were operated at 1000 Volts DC.

The state of Baden-Württemberg acquired the MBE on 1 March 1955 and the Central Baden Railways (Mittelbadischen Eisenbahnen) took over operations on 29 March 1955. It found that the railway was in very poor condition and that modernisation would not be affordable. It ended all rail traffic on 22 May 1955 and dismantled all track of the MBE by 1970. Apart from the station building in Badenweiler, all of the line's structures had disappeared by 2016.^[10] The station building was demolished in July 2022, so that high speed tracks could be built in its place for the Karlsruhe–Basel high-speed railway. The design of its replacement was still unclear at the end of 2021. As a temporary measure, a temporary structure built out of containers was installed in 2022.^[11][12]