The tunnel runs from the western approaches to Zürich Hauptbahnhof railway station, east under the station and city centre before turning north and surfacing on the southern approach to Zürich Oerlikon railway station, and allows trains running between east and west to pass through Zürich without reversal.

It includes a new set of underground platforms at Zürich Hauptbahnhof, and carries twin standard gauge (1,435 mm or 4 ft 8+1⁄2 in) tracks electrified at 15 kV AC 16 2/3 Hz using overhead catenary.

[1][2] The tunnel was opened on 14 June 2014, and forms part of the Altstetten–Zürich–Oerlikon cross-city line, also known as the Durchmesserlinie Zürich, which also includes new elevated approach tracks from Altstetten to Zürich Hauptbahnhof, and the rebuilding of Oerlikon station with two additional tracks and platforms.

At Zürich Hauptbahnhof, the tunnel serves a pair of underground island platforms, with four platform tracks, numbered as Hauptbahnhof tracks 31 to 34 but sometimes referred to as Löwenstrasse station.

All three tunnels emerge from adjacent portals to the south of Oerlikon station.