The Wilma tunnel boring machine (TBM) has completed 5 km of excavation in the western main tunnel, marking a success for the Pfons–Brenner section, part of the Brenner Base Tunnel (BBt).
The Wilma TBM started operating in September 2024, digging the 5 km northward in a year and a half. The machine has covered approximately 70% of the total length, with about 2.4 km of tunnel remaining to be excavated until the completion of the 7.4 km tunnel.
At the same time, work is also progressing in the main eastern tunnel, where the Olga TBM, also known as the “twin sister” of the Wilma machine, has already completed almost half of its route. The Olga TBM is currently drilling through the mountain over a distance of more than 7.6 km, also in a northward direction.
“The year 2026 thus begins with promising results and a decisive contribution to the future longest underground railway link in the world, a visionary infrastructure dedicated to European mobility,” says BBT SE, the company responsible for the construction of the Brenner Base Tunnel.
The Pfons–Brenner section is an essential and final section of the Austrian part of the Brenner Base Tunnel (BBT) railway project, connecting Pfons with the Italian border. During 2025, major progress was made on this section, with important breakthroughs in the eastern and western main tunnels. These decisive steps bring the project closer to completion and consolidate the construction of the world’s longest underground rail link, with a significant impact on European transport.
The Brenner Base Tunnel (BBT) connects Tulfes/Innsbruck in Austria with Fortezza in northern Italy. The total length of the tunnel is 64 km, and the length of the base tunnel is 55 km. The entire project consists of the creation of a tunnel system with a total length of 230 km.
The Brenner Base Tunnel will be operational in 2032, 16 years behind the original schedule and four years behind the estimate made in a 2020 report by the European Court of Auditors (ECA). According to the updated ECA report (in November 2025) and published in January 2026, the project costs have increased by 40% compared to the initial total estimate. In 2019, the project was estimated at 5.97 billion EUR, and a recent estimate shows costs of 8.5 billion EUR. The ECA report for 2025 shows that the investment has been revised to 8.37 billion EUR, down 1% from the 2020 report.
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