Tunnelling under Swiss mountain

6 November 2002 13:26

20 years of planning and preparation and a referendum among the Swiss population preceded the project: the construction of a new rail link between Bern and Zurich. Today, however, the implementation of all the associated sub-projects is in full swing. The most spectacular part is the Onzberg passage, where Wayss & Freytag Ingenieurbau is involved in the excavation work.

Together with Swiss partners, Wayss & Freytag Ingenieurbau is engaged in the construction of the 3.2 kilometre double-track Onzbergtunnel, a contract worth €56 million.

The spectacular element is particularly the grade-separated intersection with another rail tunnel, which connects to the main tunnel underground.

The tunnel will be drilled over a length of 2.3 kilometres. The TBM, with an external diameter of 12.4 metres, has already travelled 1,600 metres since September 2001, progressing an average distance of 25 to 30 metres a day. The drilling process should be finished in December 2002. The carcass is planned for completion in December 2003, after which the rail builders can start work.