Albtalbahn
Traffic on the Alb Valley Railway increased in the first years of its operation, but after the First World War the railway faced increasing economic difficulties. The operation could only be maintained with financial support from the district of Karlsruhe, leading to a reduction in services in the timetable. The city of Karlsruhe introduced in the mid-1920s a parallel bus service between Karlsruhe and Rüppurr, reducing the economic viability of the railway.