Valley Railway share tracks between Eutingen und Horb. The line crosses six districts of the state of Baden-Württemberg, plus the district of Stuttgart, and is part of 5 public transport associations. In the Stuttgart area, and in the district of Böblingen, namely between Stuttgart Hbf and Bondorf, the line is part of the transport-and-tariff association Stuttgart (Verkehrs- und Tarifverbund Stuttgart (VVS)). The station in Ergenzingen is the only station in the district of Tübingen, and is part of the Neckar-Alb-Donau transport association (Verkehrsverbund Neckar-Alb-Donau (NALDO)). Between Eutingen and the industrial station at Neckarhausen, the route traverses the district of Freudenstadt, and its transport association (Verkehrs-Gemeinschaft Landkreis Freudenstadt (VGS)). From Sulz am Neckar to Rottweil-Neufra, the Gäubahn crosses the district of Rottweil, and the transport association (Verkehrsverbund Rottweil (VVR)). Traveling from Aldingen to Tuttlingen, the line then makes its way through the district of Tuttlingen, and its transport association (Verkehrsverbund Tuttlingen (TUTicket)) to Hattigen. History History of the name Gäubahn and Overview The Gäu line from Stuttgart to Singen was originally cobbled together using a collection of sections of smaller railways, and these only combined in 1934 to become the line as it is today. The term Gäubahn was initially used as the name of the railway running from Stuttgart via Eutingen im Gäu to Freudenstadt, which largely travels through the Gäu, and which was put into service in 1879. Only in the section from Stuttgart to Eutingen do the two identically named lines share tracks. However, the section between Eutingen and Freudenstadt is also called the Gäubahn today. Before 1934, the name Gäubahn was used for the section Stuttgart-Eutingen, which became an important part of north-south train connections, as well as the name for the section of the Nagold Valley Railway (Nagoldtalbahn) between Eutingen and Horb am Neckar, and for the section of the Upper Neckar Railway (Obere Neckarbahn) between Horb, via Tuttlingen, to Immendingen. Therefore, by 1934 the name Gäubahn was synonymous for the railway sections between Stuttgart and Immendingen, on the border between Württemberg and Baden. In 1934, the name started to be used in yet another form: When the connection between Tuttlingen and Hattingen was completed, this line then connected the Gäu line to the section of the Black Forest line between Hattingen and Singen, forming a contiguous railway between Stuttgart and the Swiss border near Singen. This entire railway then adopted the term Gäubahn. The section