Excavation work on the Italian side of the Brenner Base Tunnel, the world’s longest railway tunnel, has been completed. The consortium led by Webuild, on behalf of BBT SE – the client company controlled on the Italian side by RFI (FS Italiane Group) through TFB (Tunnel Ferroviario del Brennero) – has finished the excavation of the west main tunnel using the 10.71m diameter TBM “Flavia”. The TBM has bored beneath the Alps for the Mules 2–3 lot, reaching the border with Austria. The east main tunnel was already completed in 2023, and overall progress on Lot Mules 2–3 now stands at over 95%.
Once the Brenner Base Tunnel, the world’s longest railway tunnel, is completed, with its 64km in total, will redesign transport between Italy and Austria, strengthening Europe’s sustainable mobility and reducing the environmental impact of transport in the Alpine area. The project work is part of the Munich-Verona railway axis. It also represents a central element of the Scandinavian-Mediterranean Corridor of the TEN-T network, of which it is also the most important section because it allows to go beyond the natural barrier formed by the Alps.
The Tunnel will connect the cities of Fortezza, approximately 50km north of Bolzano, and Innsbruck in Austria. It is called a “Base” tunnel because it runs beneath the Brenner Pass at its base, at an altitude of approximately 800m above sea level. Along its route, passenger trains will be able to travel at speeds of up to 250km/h, cutting travel time from the current 80 minutes to just 25. The Mules 2-3 Lot, which represents the main section of the Italian side of the Tunnel, is a key component of the project. It involves the excavation of a complex system of 65km of tunnels, over 40km of which were bored using TBMs. This section has also seen work by TBM “Virginia”, which completed its journey in March 2023 after finishing the excavation of the eastern main tunnel.
Flavia’s journey began in April 2019, the TBM used to excavate 14.3km along the west main tunnel on the Italian side of the BBT project.
Along Flavia’s route, more than 65,000 precast concrete segments were installed inside the tunnel.
Before Flavia, two TBMs had already reached the state border. Serena, the TBM that excavated most of the exploratory tunnel on the Italian side, arrived at the Brenner in November 2021. Virginia, Flavia’s “twin sister,” reached the Brenner in March 2023. And finally, Flavia: in total, the three TBMs used in the direction of the Brenner excavated nearly 43km.
Alessandro Marottoli, Project Manager for lot Mules 2-3, confirms:
“The determination of the TBM operators and all the professionals involved allowed us to complete another great achievement. After Serena and Virginia, Flavia too has reached her destination.”
“In April 2023, about 3.5km from the Brenner arrival point, TBM Flavia came to a halt. Due to the high overburden of over 1,200m and the low resistance of fractured rock, the rock mass pressed against the cutterhead, preventing it from advancing for several months. After several attempts, the TBM resumed excavation and, after an adventurous journey, we are now witnessing a highly significant result,” explains Stefan Skuk, geologist at BBT SE.
Photo credit: BBT SE
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