In Wildegg, the Seetal Railway formerly branched off to the south towards Lenzburg, but operations on this part of the line were closed in 1984.

It was planned to continue the line via Turgi, through the lower Aare valley to Koblenz and along the Rhine to Basel.

In 1850, a national council commission with the help of the English railway engineer Robert Stephenson recommended, among other things, that the connection between Zurich and Basel should not run via Koblenz, but instead via Olten.

Therefore, the Swiss Northeastern Railway (Schweizerische Nordostbahn) planned the continuation from Baden along the Limmat to Turgi, then along the Aare to Aarau.

The electrification with the usual Swiss Federal Railway (SBB) system of 15 kV 16 2/3 Hz was completed on 21 January 1925.