The Limmat Valley is of primary historical importance for Swiss public transport as it is the location of the Spanisch-Brötli-Bahn, the first railway line of the country, operational since 1847.

A light rail line, the Limmattal tramway, was operational since 1900, but closed in stages between 1928 and 1955, being replaced by buses.

Construction commenced in August 2017, and phase 1 between Farbhof and Schlieren opened in September 2019,[1] operated by Verkehrsbetriebe Zürich and served by an extension of the existing tram line 2 from Zürich Tiefenbrunnen railway station at the shore of Lake Zurich.

A joint order, with Baselland Transport, was placed with Stadler for the supply of light rail vehicles to operate the service from Altstetten to Killwangen.

[3][13][14] The Federal Office of Transport granted authorization in 22 February 2020 for the construction of a depot for the line 20 at Müsli, between Dietikon and Spreitenbach.