Excavation works for the Brenner Base Tunnel (BBT) on the Italian side are officially finished. The team handling the tunnel-boring machine (TBM) Flavia completed the digging of the Italian section of the future west tube. On the Austrian side, a little over 19 kilometres of main tunnels still need to be dug.
The excavations on the Italian side were carried out by three TBMs: Serena was deployed to dig the exploratory tunnel and reached the Italy-Austria border in 2021. Virginia took care of the east tunnel and reached the Brenner border in March 2023. Flavia reached Austria on Monday 5 May 2025. Flavia’s slight delay was also due to a forced break due to geological issues in April 2023.
The three TMBs dug a total of 43 kilometres of tunnels. Excavation was not the only task for the machines and the teams manning them. While digging, prefabricated tubbing rings were also placed to coat both tubes on the Italian side of the BBT. On the Austrian side, excavations are continuing on the Sill Gorge-Pfons (to be completed by 2028) and Pfons-Brenner (to be completed by 2029) sections, where respectively three and 16 kilometres of tunnels still need to be dug.
The Brenner Base Tunnel
With roughly 64 kilometres in total length, the BTT will be the world’s longest railway tunnel and will become the main border crossing between Italy and Austria. Construction started in 2007, and a grand opening is not expected before 2032. The line will connect Fortezza and Innsbruck, replacing the old Brenner Railway which unravels through the mountains.
The new infrastructure would create a much improved link along the TEN-T Scandinavian-Mediterranean Corridor, on the Verona-Munich axis. The project should cost a little over 10 billion euros. Once the tunnel is completed, freight trains running from Fortezza to Innsbruck will take 25 minutes instead of the current 80.