Since the nationalisation of the GB in 1909, the entire route has belonged to the Swiss Federal Railways (Schweizerische Bundesbahnen, SBB).

This is followed by the 3,359 metre-long, single-track Albis Tunnel and then the Litti operations yard, from where the line has run as a double track to Baar since 1979.

A stress test was carried out on the newly built bridge with eight Ae 4/7 locomotives during the night from 28 to 29 March 1981.

In order to be able to achieve a half-hourly journey for express trains on the route from Zurich to Ticino, a second track has been built near Walchwil between June 2019 and December 2020.

Regional traffic has been served by buses during this period, while long-distance trains was diverted via the western side of Lake Zug.

Changes included 1.7 kilometres (1.1 mi) of double-tracking north of Walchwil and enlarging tunnels to allow double-decker trains.