Austria and Italy have reached one of the most significant milestones in the construction of the Brenner Base Tunnel (BBT) after the two main bores of the future railway line were broken through almost simultaneously beneath the Alps.
The breakthrough, achieved on 28 July, marks the first cross-border railway connection through the tunnel’s two main tubes and represents another decisive step forward for one of Europe’s largest rail infrastructure projects.
The historic moment took place in the H53 Pfons–Brenner construction section on the Austrian side, where the final layers of rock separating Austria from Italy were removed in both main tunnels. At 10:35, the final breakthrough was completed, allowing miners and project managers to pass through the new tunnels into Italy for the first time, where they met their Italian counterparts.
This milestone connects the main tunnels excavated in Austria with those already completed in the Italian H61 Mules 2–3 construction section, around 1,400 metres beneath the Brenner Pass. Following the breakthrough of the exploratory tunnel in September 2025, Austria and Italy are now linked through both main railway tunnels.
“With the connection of the two main tunnels, our project has reached another major milestone. In future, freight and passenger trains travelling between Austria and Italy will pass through here. This success is a remarkable demonstration of what can be achieved when two countries work together towards a common goal. The project has many names, but above all it bears the signature of the people who built it day after day,” said Martin Gradnitzer and Umberto Lebruto, Members of the Executive Board of BBT SE.
Two excavation methods, one shared objective
The breakthrough also marks the convergence of two construction sites that have been progressing independently for several years. On the Italian side, the tunnels were excavated using the tunnel boring machines Virginia and Flavia, while the Austrian section was driven using conventional drill-and-blast methods.
The success of the operation also relied on exceptional surveying accuracy. Measurements taken during the excavation of the exploratory tunnel recorded a deviation of only a few centimetres at the 2025 breakthrough, while the alignment achieved during the connection of the main tunnels was even more precise.
“Tunnel construction means facing new challenges every single day. Throughout this project, the mountain constantly tested us with unexpected conditions. I would like to express my sincere gratitude to the ARGE H53 consortium, comprising PORR and Marti, as well as to the site supervision team, for their outstanding professionalism and dedication,” said Michael Knapp, Project Manager for the H53 Pfons–Brenner section.
Alessandro Marottoli, Project Manager for the Italian H61 Mules section, also highlighted the importance of the achievement.
“Today marks another historic day for this project. The fact that Italy and Austria are now connected through three tunnels of the Brenner Base Tunnel is a source of great pride for the entire BBT team, who work tirelessly on both sides of the border towards a common goal.”
Project representatives stressed that the true heroes behind this achievement are the miners, blasters, machine operators, electricians, surveyors, geologists, safety specialists and engineers who have spent years working under some of the most demanding conditions deep beneath the Alps.
Following this latest milestone, work will continue towards Innsbruck, where the tunnel boring machines Wilma and Olga will complete excavation of the remaining sections of the main tunnels. Once these works are finished, the entire Brenner Base Tunnel railway system will be fully connected, bringing the project another step closer to entering service and transforming the Austria–Italy corridor into one of Europe’s most important rail routes for both passenger and freight transport.
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