U-Bahn station was opened on 15 February 1912. In 1918 the station expanded to its current six platform tracks during the construction of the Walddörfer (forest villages) Railway, now part of U-Bahn line U2. Alte Wöhr station was opened in 1931 under the name of Stadtpark. It was renamed in the early 1970s to avoid confusion with the nearby U-Bahn station then also called Stadtpark, but now called Saarlandstraße. Rübenkamp station was opened in 1913 to serve the new hospital in Barmbek and later the residential area of Barmbek-Nord. Ohlsdorf station was the terminus of the Stadtbahn when it opened in 1906. Since 1914 it has been possible to interchange between the S-Bahn and the U-Bahn (now line U1). In 1918, the Alster Valley Railway opened from Ohlsdorf to Poppenbüttel. In 1924 it was incorporated into the Hamburg suburban railways. In 1940, the Ohlsdorf–Poppenbüttel section became the first line of the Hamburg S-Bahn to be electrified with direct current. Just south of the station is the Hamburg-Ohlsdorf depot where all Hamburg S-Bahn trains are stored and maintained. On 11 December 2008, the underground S-Bahn line opened from Ohlsdorf to Hamburg Airport. Operations S-Bahn lines S11 (Blankenese–Ohlsdorf), S21 (Elbgaustraße–Aumühle) and S31 (Altona–Neugraben) run on the two northern tracks of the link line (the Stadtbahn). The two southern tracks are used by long-distance and regional trains. Many trains to or from the south serve not only the Hauptbahnhof, but also Altona station. The original purpose of the link line, the handling of freight traffic, is now served by the Hamburg freight bypass, running through the northern suburbs. References Footnotes Sources Railway lines in Hamburg Hamburg S-Bahn Railway lines opened in 1865