Swiss Northern Railway

It was absorbed into the Swiss Northeastern Railway (German: Schweizerische Nordostbahn, NOB) in 1853 and extended from Baden to Brugg in 1858.

It is electrified at 15 kV 16.7 Hz and its eastern 16 km section from Zürich to Killwangen-Spreitenbach is now part of the Zürich–Olten trunkline and has four tracks.

It was the first line built in Switzerland, except for the line built from Mulhouse to Basel by the French company Chemin de fer de Strasbourg à Bâle, opened to a temporary station outside Basel's walls on 15 June 1844 and to the permanent station on 11 December 1845.

In 1836 Friedrich Hünerwadel of Lenzburg pointed out to the government of the canton of Aargau—through which the line had to pass—the importance of the route of a railway from Zurich to Basel for Aargau's commerce and industry.

[1] In 1837, the Zürich Chamber of Commerce commissioned the engineer Alois Negrelli to investigate the route of such a line.

Although the Aargau parliament passed a law permitting compulsory purchase in November 1840, several shareholders lost their financial guarantees, and the company had to be dissolved in December 1841.

In May 1843 representatives of the cantons of Aargau, Zurich and Basle met in the Baden City Hall, but they failed to come to any agreement.

With an assurance that Alois Negrelli would direct the engineering and that a branch line would be later built from Baden to Lenzburg and Aarau, the Aargau parliament approved the project in July 1845.

[1] The 1,435 mm (4 ft 8+1⁄2 in) standard gauge was chosen,[2] Negrelli relocated the station in Baden to the north side of the town, requiring the construction of the 80-meter-long Schlossberg tunnel.

At the end of 1845 the Nordbahn company was founded with a share capital of 20 million francs, in the spring of 1846 construction work started.