The A3 motorway section at the Kerenzerberg tunnel in the direction of Sargans has been in operation for over 30 years. In order to ensure road safety for the coming years and long-term operation, the OFROU (Federal Roads Office) is carrying out a complete renewal of the Weesen - Murg section. Firstly, a new 5.5km safety tunnel will be built, then the repair of the Kerenzberg tunnel will be started. The new safety tunnel,  on the lake side and parallel to the existing Kerenzberg tunnel, will be driven from both sides.

On the West side at Gäsi portal the site installation began on the 02/03/2020. The access to the tunnel adit is available via a temporary auxiliary bridge over the Escher Canal. The site installation in Tiefenwinkel (east side)  will start on the 23/03/2020.

Tunneling work will take place on both sides in autumn 2020. Construction time will be about 4 years for the safety tunnel, without significant traffic restrictions on the national road.

The new 5.5 km long safety tunnel  will then be connected with Kerenzeberg tunnel with a bypass.  A modern ventilation system will ensure, in the event of a fire in the tunnel,  that the hot flue gases are extracted into a ventilation duct and then directed outside. Preliminary works for the repair of the existing Kerenzeberg tunnel will begin in mid-2023 and it is expected to last until the end of 2026.

For further information please click ch/64 for the tunnelbuilder archive and also visit https://www.astra.admin.ch. 12/20.

l