Zimmerberg tunnel
The Zimmerberg tunnel is a 1984 meter long single-track railway tunnel through the Zimmerberg . It is entirely located in the municipality of Horgen , in the Swiss canton of Zurich .
The tunnel was opened on June 1, 1897 by the Schweizerische Nordostbahn (NOB) as part of the Thalwil – Arth-Goldau railway , which serves as the access to the Gotthard Railway from Zurich. Today the line belongs to the Swiss Federal Railways (SBB). The access route from Zurich to Horgen Oberdorf has been expanded to two lanes and will become a single lane in the railway station of the same name in front of the eastern tunnel portal.
When leaving the western tunnel portal at Sihlbrugg Station , the Sihl is crossed, the Sihl Valley Railway followed shortly before the eponymous railway station, which is also the apex of the route. Shortly after the train station, the railway line disappears into the Albis tunnel , which is also single-track .
The single-lane Zimmerberg tunnel and the adjoining Albis tunnel form a bottleneck between Zurich and Zug. To eliminate this bottleneck, the Zimmerberg Base Tunnel was designed, which would make the line double-track throughout and at the same time eliminate the 13 per thousand ramps on the Zurich Gotthard approach.
Two-lane expansion of the route with shallow tunnels
The Zurich – Thalwil section, which has been in operation since 2000 - actually a flank tunnel - is now often referred to simply as the Zimmerberg tunnel, although this is the name given to the single-lane tunnel between Horgen Oberdorf and Sihlbrugg that was opened in 1897. The travel time of the long-distance trains between Zurich main station and Thalwil has been shortened by two to three minutes thanks to the new base tunnel .
This expansion project was divided into two stages and the first stage (Zurich – Thalwil) was implemented as part of Bahn 2000 ; the second stage (Thalwil – Litti / Baar) should have been implemented as part of AlpTransit for the Gotthard axis, but was postponed for an indefinite period due to the lack of funding.
Coordinates: 47 ° 15 '1.5 " N , 8 ° 35' 4.5" E ; CH1903: 686 747 / 233913