The Wolfenbüttel–Helmstedt railway is a 51 km-long railway line in the south-east of the German state of Lower Saxony. It was opened in 1843 and 1858 in two stages. It opened up the area south of the Elm hills and was therefore also called the South Elm Railway (German: Südelmbahn). The main intermediate stations were Schöningen and Schöppenstedt, which were connected to Helmstedt and via Wolfenbüttel to Brunswick. The 33 km section between Schöppenstedt and Helmstedt was closed on 8 December 2007, leaving only the western section in operation. The section from Wolfenbüttel to Jerxheim was opened in 1843 and was one of the oldest railways in Germany and part of the main line between Berlin and western Germany until the opening of the Berlin–Lehrte railway in 1871.
In 1838 Wolfenbüttel was connected by rail to Brunswick with the opening of the Brunswick–Bad Harzburg line. On 10 July 1843 a line was opened by the Duchy of Brunswick State Railway from Wolfenbüttel to the Magdeburg–Halberstadt line at Oschersleben via Schöppenstedt, Jerxheim and Gunsleben. Until the opening of Berlin–Lehrte railway in 1871 this was part of the shortest connection between Hanover and Berlin.
A branch line built was opened on 20 July 1858 from Jerxheim to Helmstedt via Schöningen. This new line involved less construction and crossed easier terrain than the direct Brunswick–Helmstedt line opened in 1872, which forms part of the present Brunswick–Magdeburg line. Other lines were built connecting to the Wolfenbüttel–Helmstedt line, particularly at Jerxheim. On 1 May 1868 a link was opened between Jerxheim and Börßum, connecting to the Brunswick Southern Railway to Kreiensen (the western section of this line is now the Warne Valley Railway from Börßum to Salzgitter-Bad). On 15 September 1872 the Eilsleben–Völpke–Schöningen line opened. These lines were particularly important for long-distance freight trains and also were used by occasional express passenger trains. Later branch lines were added to Dedeleben and Nienhagen and the Brunswick-Schöningen line. The sections from Wolfenbüttel to Jerxheim and between Schöningen and Helmstedt, however, had only medium importance and were not used by express trains in 1914 or 1939.
Following the separation of East and West Germany by the Inner German border after World War II, only the Helmstedt–Magdeburg line of the lines north of the Harz continued to operate over the border. As a result, the Jerxheim–Börßum link lost its importance and was closed for passengers in 1976 and for freight in 1988. Between the border and the Elm hills, only the Wolfenbüttel–Jerxheim–Helmstedt line was left. It was maintained despite moderate traffic to connect with the lignite mines in the Helmstedt district and the Buschhaus Power Station. The line between Wolfenbüttel and Schöppenstedt it is now operated as a branch.
After German re-unification there was much consideration of the reopening of the lines in the vicinity, including the Jerxheim–Dedeleben line to provide a connection between Halberstadt and Helmstedt and Brunswick, but this did not proceed. Since the reopening of the Halberstadt–Vienenburg line in 1996 and the closure of the line to Dedeleben in 2001, the reopening of the line is no longer under discussion.
A relocation of the railway line to allow the expansion of the mines was considered too costly, instead it was abandoned between Schöppenstedt and Schöningen in December 2007. This saved resources, which are available for a proposal to build a regional light railway between Brunswick and Schöppenstedt. The implementation of this project is uncertain.
Meanwhile, parts of the line between Helmstedt and Schöningen were removed for open cast mining in 2009.