Brenner Base Tunnel’s western main bore breaks through

The western main bore of the Brenner Base Tunnel has broken through, ORF reported on Tuesday, creating a continuous 55-kilometre tunnel connection from Innsbruck to Franzensfeste in South Tyrol.

Tunnel-boring machine Wilma completed the breakthrough after nearly two years of work. The connection links numerous separate tunnel sections between the Sillschlucht area near Innsbruck and Franzensfeste.

Wilma began operating on 18 September 2024 and excavated around 7,500 metres of rock. During the work, the machine encountered geological fault zones where the characteristics of the mountain changed within a few metres, presenting significant challenges for the project teams.

The machine is 180 metres long, has a drilling diameter of 10.37 metres and weighs 2,700 tonnes. Its operations included the automated installation of concrete segments to secure the tunnel walls, the removal of excavated material, technical maintenance and monitoring of geological conditions.

Logistics also played a key role in the work, according to Michael Knapp, project manager for the Pfons-Brenner construction section. The project team aimed to limit transport by road and said this saved around 45,000 truck journeys.

The concrete segments, each weighing about 10 tonnes, were delivered by rail via the Wolf rail connection and prepared for installation inside the tunnel-boring machine. Excavated rock was transported by conveyor directly from the construction site to the nearby Padastertal disposal site.