Left:
Installation of twin-shaft mixer
is scheduled in 2030, Fedro’s improvement project will then renovate the current tunnel. Traffic is to be able to run through both tubes from 2033. The tunnel will also house an infrastructure channel for third party companies, for example the Swiss national grid company, which would replace the high voltage transmission line over the Gotthard Pass. The new power cable would be located along the dedicated channel, below the roadway. Fedro estimates the total project cost of building the
new tube and renovating the existing tube to be SFr2.14 billion (incl VAT), or US$2.7 billion, £2.0 billion. Safety was, is and will be the highest concern of
Fedro and all the companies involved in the construction. The existing service and infrastructure tunnel (SISto) will run between the two main tubes. It is connected to the main tunnel via 68 No. cross-passages. It has its own ventilation system, at a higher pressure than the main tunnel to prevent smoke or gas entering. Construction work also has had to be done on the
SISto, including: its entrances have been moved to make way for those of the second tube; and five new underground ventilation centres are being built for connection to the SISto.
Due to its enormous length, the project was divided
in two sections, North and South. The tunnel mouth of the northern part is located in the German-speaking mountain region Göschenen, next to the ski resort Andermatt; the portal of the southern part is located in the Italian speaking town Airolo. Due to the length of the tunnel, a TBM is drilling from the south end at the same time as another TBM is drilling from the north. In 2027 the breakthrough of the main tunnel is expected. Fedro awarded the contract for the North package
of tunnel works to the JV Implenia (60%) and Frutiger (40%). The tunnel is 12.3m-diameter and the majority of
the Northern section (7.3km) is to be excavated by TBM and lined with concrete segmental rings. The TBM was installed in February 2025 and started to work after a 160m-long conventionally mined section. A section of 460m-long required a special heading through a fault zone and had to be mined conventionally. The TBM will then be towed through this area and the time will be used to completely overhaul the cutterhead. To make the actual breakthrough between the North and the South section of the new tunnel, the rock will be blasted.
Left:
Installation of cement screws in the tunnel PHOTO CREDIT: FEDRO
November 2025
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