Brenner Base Tunnel: Europe’s Longest Rail Link – Impact & Innovations

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Introduction

The Brenner Base Tunnel (BBT) project achieved a major milestone in September 2025 with the first physical connection between Italy and Austria. This connection, established at a depth of around 800 metres, involved engineers breaking through a 400-metre section of rock in the exploratory tunnel beneath the Brenner Pass.

Project Overview

The BBT, when completed, will span 64 kilometers between Fortezza in Italy’s South Tyrol and Innsbruck in Austria, including the Innsbruck bypass, making it the world’s longest underground rail link, surpassing Switzerland’s Gotthard Base Tunnel. This project is a core component of the Scandinavian–Mediterranean corridor, one of the EU’s priority transport routes.

Construction and Engineering

The exploratory tunnel runs 12 metres beneath the alignment of the future twin rail tunnels. Contractors have used advanced tunnel boring machines (TBMs), capable of excavating up to 20 metres per day. The breakthrough required precise alignment of excavation fronts, demonstrating international cooperation. Geological challenges, including fractured rock and water inflows, continue to shape the progress of the project. More than half of the tunnel system has been excavated.

Impact and Benefits

The BBT will facilitate the shift of freight and passenger traffic from road to rail. Travel time between Innsbruck and Fortezza will decrease from two hours to 25 minutes. The project is expected to reduce CO₂ emissions by an estimated 1.5 million tonnes annually and alleviate congestion, noise, and pollution in Alpine valleys. The construction phase currently supports approximately 4,000 jobs across Austria and Italy. Passenger trains will operate at speeds of up to 250 km/h. A single freight train through the tunnel could replace up to 150 lorries on Alpine roads.

Management and Funding

The project is managed by BBT SE, which is jointly owned by Austria and Italy, with substantial funding from the European Union. The EU supports the BBT through the Connecting Europe Facility, viewing it as essential to its climate and connectivity goals. Once open in the early 2030s, the BBT will accommodate around 400 trains a day.

Conclusion

The Brenner Base Tunnel project has achieved a key milestone with the initial connection between Italy and Austria. The project, set to be the world’s longest rail tunnel, is designed to enhance transport efficiency, reduce emissions, and foster regional integration.

Company Summary

BBT SE: A company jointly owned by Austria and Italy, managing the Brenner Base Tunnel project.

Technology

TBMs: Tunnel Boring Machines, used for excavating tunnels, capable of excavating up to 20 meters per day.

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