Brugg and opened to Aarau on 15 May 1858, where it met the line from Olten built by the Schweizerische Centralbahn. The line was incorporated in the Swiss Federal Railways on 1 January 1902. The whole line from Zürich to Olten was electrified on 25 January 1925. Heitersberg Tunnel On 23 June 1874 the Aargau Southern Railway (German: Aargauische Südbahn, AS) was opened from Rupperswil to Wohlen as part of the project to connect the Gotthard Railway to Olten and Basel, largely for freight trains. On 6 September 1877 the Swiss National Railway (German: Schweizerische Nationalbahn) opened a line from Wettingen to Zofingen as part of a plan to connect Singen, Germany and Lake Geneva in competition with the established railway companies. The line went bankrupt in 1878 and was taken over by the NOB. Part of this line between Mellingen and Gexi junction (near Hendschiken) together with the AS line between Gexi junction and Rupperswil was incorporated into the current main line between Zürich and Olten when a shorter and straighter line between Killwangen-Spreitenbach and Rupperswil was opened through the long Heitersberg Tunnel on 22 May 1975. Notes References Railway lines in Switzerland Railway lines opened in 1847 1847 establishments in Switzerland Swiss Federal Railways lines 15 kV AC railway electrification it:Ferrovia Zurigo-Baden