The 16.9 km long Gotthard road tunnel needs to be closed to traffic during renovation work necessitated by its age. To ensure the important north-south connection can nevertheless be maintained, a second, parallel tube is being built and then the existing tunnel will be renovated. 

Preparations for construction of the second tube include the construction of two access tunnels. For this, Herrenknecht received orders for two tunnel boring machines – a Single Shield TBM (Ø 7,390 mm) for the southern tunnel and a Gripper TBM (Ø 7,000 mm) for the northern tunnel. The official factory acceptance of the Single Shield TBM took place in January 2022, the acceptance of the second machine in May 2022. The miners started the mechanized excavation of the southern access tunnel in June 2022 and in August 2022 of the northern tunnel. The miners successfully finished the mechanized excavation of the access tunnels as early as April and August 2023.

The construction companies will employ two Herrenknecht Single Shield TBMs (Ø 12,310mm in the south and Ø 12,225mm in the north) for the construction of the second main tunnel.

Once all work on both tunnels has been completed, one tunnel each with one lane (plus emergency lane) will be available for southbound and northbound traffic. A significant increase in safety compared to previous operation with twoway traffic in one tube.