Since May and June of 2023, the two TBMs Lilia and Ida have been working southwards on the Austrian H41 Sill Gorge-Pfons construction site of the BBT project. The excavation work is being carried out by RTI H41.

TBM Ida has spent about 18 months working under highly challenging geological conditions and on the 26/01/2025 completed excavation of the first 6 km out of a total of 8.4 km of the main west tunnel of the Brenner Base Tunnel.

 After crossing through two major fault zones, named Viggarta and Walzn with no problems, there was a third fault zone, Werner, located below the Arztal valley in the municipality of Pfons. This fault zone was  about 35 m thick, but was also passed without any problems in January. TBM Ida has already covered approximately three quarters of its route, excavated 510,000 m³ of rock and installed 21,500 segments in the west line tunnel. The segments are produced directly at the Ahrental construction site, thus saving as many as 27,000 truck trips on the local roads. The TBM will reach its final destination in the municipality of Navis in the coming months. 

TBM Lilia, Ida's twin, has so far progressed about 5.4 km and is expected to complete excavation of the main east tunnel within this year.

Project status

The Brenner Base Tunnel is a 230 km tunnel system. To date, 185 km of tunnels have already been excavated: 84 km for train transit, 56 km for exploratory tunnels and 45 km of other tunnels.

For further information on the project click here, at/16 and it/103 for the tunnelbuilder archive and also visit  https://www.bbt-se.com/. 05/24.