This project is part of a broader discussion on major international rail infrastructure developments and relates to long-distance train routes.

The project is planned to open in 2032 and will ultimately form a long, continuous underground railway corridor between the two countries.

A notable feature is an exploratory tunnel running the full length of the BBT to study rock mass and drainage and to help reduce costs and construction time.

Construction details highlight ongoing exploratory tunnel work, which is expected to reduce future costs and shorten timelines while informing engineers about surrounding geology.

The estimated construction cost is about 8.54 billion euros (around 7.4 billion pounds).

The Brenner Base Tunnel comprises a 55-kilometer (34-mile) railway tunnel designed for both passenger and freight trains, with a projected cost of about 8.54 billion euros.

The Brenner Base Tunnel is a major rail project under construction that will create a continuous underground corridor between Innsbruck, Austria and Fortezza/Franzensfeste, Italy, and will become the world’s longest tunnel when it opens in 2032.

An Inn Valley tunnel, 12.7 kilometers long, already opened in May 1994 and forms part of the existing route, expanding the overall underground connection to about 64 kilometers.

The Inn Valley bypass links with the Brenner Base Tunnel, creating a combined 64-kilometer underground route for passenger and freight trains.

When finished, the BBT will be the longest underground railway connection in the world, linking Austria and Italy across two time zones.

Plans aim to connect Innsbruck and Fortezza/Franzensfeste in a single railway corridor, with the BBT improving drainage and construction efficiency through the exploratory tunnel.

The exploratory tunnel sits about 12 meters below the main tunnels and has a 5-meter diameter, designed to optimize costs and schedule.