Hirschengraben Tunnel

The Hirschengraben Tunnel is a railway tunnel in the Swiss city of Zürich. The tunnel runs from the western approaches to Zürich Hauptbahnhof railway station, east under the station, the river Limmat and city centre before turning south and surfacing at Zürich Stadelhofen station. It includes a set of underground platforms at Zürich Hauptbahnhof, and carries twin standard gauge tracks electrified at 15 kV AC 16,7 Hz using overhead catenary.
The tunnel was opened in 1989, and initially allowed trains to run through Zürich onto the Lake Zürich right bank line without reversal. The original routing of the right bank line, which departed from Zürich Hauptbahnhof station in a westerly direction before performing a clockwise 270 degrees turn via a viaduct over the Limmat and passing through Letten station and the Letten Tunnel to Stadelhofen, was closed after the opening of the Hirschengraben Tunnel. The following year, the Zürichberg Tunnel opened from a junction to the south of Stadelhofen to Stettbach station, thus allowing trains to run to and from points to the east and north of Zurich without reversal.

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