The Wutach Valley Railway is a 61.7-kilometer-long, standard-gauge, single-track railway line. It connects Lauchringen station, on the High Rhine Railway, with the Hintschingen junction near Immendingen, where it joins the Black Forest Railway.
The winding route of the middle section, and especially the reversing tunnel in the Stockhalde, gave it its nickname, the Sauschwänzle Railway.
The line was built for strategic reasons for the military and opened in 1890. Because the standard railway line partially runs through Switzerland, the aim was to bypass it.
Because the geography of the Wutach Valley in the middle section, from Weizen to Blumberg, resulted in an elevation difference of over 230 meters, the line had to be artificially extended. At just 9.6 km as the crow flies, the railway line is 25 kilometers long. This artificial extension was achieved with several bridges, a circular reversing tunnel, and a double loop. The circular reversing tunnel is the only structure of its kind in all of Germany. With a gradient of only 10 ‰, heavy (military) trains could be transported without additional traction.
Since this artificial extension of the line also increased ticket prices and travel times, passenger service was insignificant and was discontinued on the central section in 1967.
Today, the central section is used for heritage services, usually with steam locomotives.