Zimmerberg Base Tunnel
| Overview | |
|---|---|
| Line | Gotthard Line |
| Location | Zürich, Switzerland |
| Coordinates | 47°19′40″N 8°31′52″E / 47.3277°N 8.5312°E |
| Status | Active since 2003 |
| System | Swiss Federal Railways (SBB CFF FFS) |
| Start | Zürich |
| End | Thalwil |
| Operation | |
| Opened | April 2003 |
| Owner | SBB Infrastructure |
| Operator | SBB CFF FFS |
| Traffic | Railway |
| Character | Passenger and freight |
| Technical | |
| Length | 9.4 km (5.8 mi) |
| No. of tracks | 2 |
| Track gauge | 1,435 mm (4 ft 8+1⁄2 in) (standard gauge) |
| Electrified | 15 kV 16.7 Hz |
| Operating speed | 160 km/h (99 mph) |
The Zimmerberg Base Tunnel (ZBT) is a railway tunnel under the Zimmerberg mountains in Switzerland. Phase I of the tunnel was opened to traffic during April 2003.
The ZBT has been divided into two phases of work; as of 2024, only Phase I is operational while Phase II remains in the planning and preparation stages. Zimmerberg I is about 10 km long; it links Zürich with Thalwil, bypassing a section of the Lake Zürich left-bank railway line, which allows rail traffic to traverse the mountains more efficiently.