TUNNELLING on the Brenner Base Tunnel (BBT) project, which at 64km will become the world’s longest railway tunnel when it opens in 2032, reached a key milestone on March 30 with the breakthrough of the eastern bore of Mules 2-3 section.

Webuild is overseeing construction of the lot and the arrival of TBM Virginia at the Austrian border was celebrated by Italian minister of infrastructure and transport, Mr Matteo Salvini, members of the BBT management council, Mr Gilberto Cardola and Mr Martin Gradnitzer, chief executive of Italian Rail Network (RFI), Ms Vera Fiorani, and chief executive of Webuild, Mr Pierrot Salini. The VIPs witnessed the ceremonial dyeing of the last prefabricated tunnel ring section in the Austrian and Italian national colours.

Webuild has now completed 91% of the excavations on Mule 2-3, which is described as the most challenging part of the project. Virginia excavated 14km beneath the Alps in less than four years, commencing its journey on May 22 2019, and proceeding at an average daily speed of 10.2m, installing 56,800 prefabricated tunnel rings.

The Brenner Base Tunnel will run south-north from Fortezza to Innsbruck and will reduce travel times from 1h 20min at present to 25 minutes when complete, offering a step-change in performance on the Verona - Munich line. The line is part of the Scandinavian-Mediterranean TEN-T corridor.

Mules 2-3 involves excavation of 65km of tunnels, including the two mainline tunnels as well as cross tunnels and an emergency stop, including the related access tunnel. Traditional methods are being used on 20km and TBMs on 45km of the section, which comprises 40.3km of main tunnels, 14.7km of exploratory tunnel, the emergency stop in Trens, and cross passages located every 333m.

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