Badische Hauptbahn
The first route, called the Baden Mainline ("Badische Hauptbahn"), was built in sections between 1840 and 1863. The first, 18.5 km long, section between Mannheim and Heidelberg was taken into service on 12 September 1840. Other sections followed: to Karlsruhe in 1843, Offenburg in 1844, Freiburg im Breisgau in 1845, Schliengen in 1847, Efringen-Kirchen in 1848 and Haltingen in 1851. The branches to Kehl and Baden-Baden were opened as early as 1844 and 1845 respectively. The extension of the main line through Basle territory required negotiations with the Swiss Confederation, during which differences of opinion over the best place for the junction of the Baden line to the Swiss network – Basle or Waldshut – led to delays.