Swiss engineers Frutiger and Implenia have won a contract worth $477m for work on the Sisikon Tunnel, which will form part of the Axenstrasse road along the shores of Lake Uri and Lake Lucerne.

The team will blast through the rock to allow the installation of a single 4.4km-long tunnel. They will also build access tunnels, passing places, ventilation hubs and exhaust ducts.

The external works will be carried out by Implenia’s civil engineering units, including the construction of a gallery to protect against natural hazards.

Around 2 million tonnes of excavated material will be moved by boat to a large renaturation project on the Reuss Delta in Flüelen.

A map of the A4 Neue Axenstrasse, with the Sisikon Tunnel on the right (Implenia/axen.ch)

Implenia has a 60% share of the joint venture, and Frutiger has the remaining 40%.

Christian Späth, Implenia’s head of civil engineering, said: “The creation of the Sisikon tunnel involves challenging work in a very special location, making it a perfect fit for Implenia’s strategy as a specialist in large and complex transport infrastructure.

“We will be able to contribute our extensive expertise and experience in tunnel construction and civil engineering.”

Construction is due to start in mid-2025 and be completed by 2034.