| Zimmerberg Tunnel | |
|---|---|
Tunnel portal (Sihlbrugg end) | |
![]() Interactive map of Zimmerberg Tunnel | |
| Overview | |
| Official name | German: Zimmerbergtunnel |
| Other name | German: Horgerbergtunnel[1] |
| Line | Thalwil–Arth-Goldau railway |
| Location | Zürich, Switzerland |
| Coordinates | 47°15′01″N8°35′07″E / 47.2503°N 8.5853°E / 47.2503; 8.5853 |
| Status | Active |
| System | Swiss Federal Railways (SBB CFF FFS) |
| Crosses | Zimmerberg |
| Start | Horgen Oberdorf |
| End | Sihlbrugg |
| Operation | |
| Constructed | September 1894 – August 1896 |
| Opened | June 1, 1897 (1897-06-01) |
| Owner | SBB CFF FFS |
| Operator | SBB CFF FFS |
| Traffic | Train |
| Character | Passenger and freight |
| Technical | |
| Length | 1,984 metres (6,509 ft)[note 1] |
| No. of tracks | Single |
| Track gauge | 1,435 mm (4 ft 8+1⁄2 in) |
| Electrified | 15 kV/16.7 Hz AC |
| Grade | 13‰[2] |
The Zimmerberg Tunnel is a 1,984-metre (6,509 ft)-long[note 1]railway tunnel under the Zimmerberg mountain in the Canton of Zurich, Switzerland which opened in 1897.[3][4]
Construction began in September 1894 from the Horgen portal.[1] Breakthrough was achieved on 15 March 1896, and construction finished in August 1896.[1] The tunnel was opened to traffic on 1 June 1897 along with the rest of the Thalwil–Zug railway line.[5][6][7] On 5 February 1923, electrification of the railway line, including the tunnel, was completed.[7]
Together with the Albis Tunnel, the tunnel forms the railway passage through the Zimmerberg and Albis on the Thalwil–Arth-Goldau railway line which is an important feeder to the Gotthard railway.[5]
The segment leading through the two tunnels constitutes a single-track section on the Thalwil–Arth-Goldau railway.[3][7][8]
The proposed phase II of the Zimmerberg Base Tunnel aims to resolve the bottleneck formed by the single-track sections and to allow for faster traffic on the Thalwil–Arth-Goldau railway.[9]