The multi-billion-euro Brenner Base Tunnel project has launched a single 2,000-ton machine named Kathrin to bore the South Tyrolean approach near Funes, while workers in Austria manage a massive 7.7-million-cubic-metre excavation dump in the Padaster Valley to ease decades of Alpine freight friction.
Deep in the heart of the Austrian Alps, engineers are carving out what will become the longest railway tunnel in the world. The Brenner Base Tunnel project stands as one of Europe’s biggest construction sites, designed to fundamentally reshape continental transit through the multi-billion-euro railway development. While the base tunnel itself secures prime ministers and ceremonies, the logistical reality of moving millions of cubic metres of blasted rock requires monumental civil engineering on both sides of the pass.
Excavating the South Tyrolean Approach With a Massive Reversible Borer
On the Italian side of the project, a distinct engineering feat is underway in a South Tyrolean side valley. The Fortezza-Ponte Gardena stretch serves as the first functional lot of the southern approach to the main tunnel. Operations kicked off when a colossal machine entered the ground at Funes on June 20, 2025, according to the infrastructure monitoring body OTI Nord.
Measuring 472 feet long and weighing 2,000 metric tons with a cutterhead spanning 31.8 feet, the machine named Kathrin faces an unusual logistical challenge. Rather than being abandoned or cut up for scrap after completing its first bore—as is common with heavy tunneling equipment—Kathrin must be completely disassembled, dragged backward through its own hole, and reassembled in a dedicated cavern at Funes to dig the second tube.
According to Webuild, the contractor overseeing the work, the machine has a total scope of more than 16 kilometres of tunneling across twin single-track tubes and interconnections, alongside roughly 9,000 precast concrete lining segments. The machine already proved its operational flexibility by passing safely beneath the Brenner motorway without disrupting surface traffic.
Managing Europe’s Largest Excavation Dump in the Padaster Valley
North of the main subterranean works, handling the sheer volume of extracted material presented landscape planners and geologists with an environmental puzzle. Sebastian Reimann, a project manager responsible for construction section H53 in the Pfons/Brenner tunnel segment, illustrated the scale of the task for Euronews Earth.
“We have a huge construction site here with a landfill volume of 7.7 million cubic metres of excavated material,”
Sebastian Reimann, project manager
This massive repository represents the largest excavation dump by volume in the European Union. During peak operations, four separate tunnel-boring machines advanced underground simultaneously, generating upwards of 250,000 cubic metres of spoil every month that had to be brought to the surface.
To prevent local communities from being overwhelmed by heavy lorry traffic, project engineers installed an enormous conveyor belt system running through an exclusive access tunnel. At its longest point, the conveyor belt reached 30 kilometres, hauling rock chippings directly from the mountain’s core up into the Padaster Valley without relying on road transport.
Environmental Mitigation and River Diversion in an Alpine Valley
The transformation of the Padaster Valley required careful regulatory compliance. To accommodate the massive landfill, the local Padasterbach river had to be temporarily moved. Andreas Ambrosi, a colleague of Reimann, noted the current appearance of the site.
At the moment it is still a grey stony desert,
Ambrosi conceded.
However, project planners emphasized that the disruption is temporary. A legally required 1,500-metre diversion tunnel was constructed to provide the Padasterbach with a temporary riverbed, a mandatory condition for securing approval for the mega landfill. Work on a permanent new riverbed is already underway alongside the 1,400-metre-long landfill structure, with the long-term goal of restoring a blossoming Alpine landscape within a decade.
The Legal Battle Over Alpine Freight Traffic
Beyond the engineering triumphs and environmental mitigation efforts, the entire infrastructure project carries immense geopolitical significance. For decades, the Brenner Pass has been a political flashpoint due to heavy freight traffic, generating three separate rulings from the European Court of Justice since 2005.
The legal friction persists. An Advocate General at the European Court of Justice delivered an opinion indicating that three of Austria’s current truck bans still breach European Union law. Although the opinion is non-binding and existing restrictions remain in force while the Court deliberates without a set timeline, completion of the Brenner Base Tunnel and its approaches aims to shift trans-Alpine freight onto rail, potentially resolving a 20-year legal dispute between Austria and the European Union.
