The first of two tunnel boring machines (TBMs) destined to carve out the Italian side of the Mont Cenis Base Tunnel – the core of the future Turin–Lyon railway line – has officially been delivered to the Herrenknecht plant in Germany.

Built for the UXT consortium (comprised of Itinera, Ghella and Spie Batignolles); the TBM will be begin its journey at the Chiomonte construction site in the Susa Valley, from which it will excavate the second access tunnel before continuing to bore the south tube of the base tunnel, which is already underway on the French side, advancing as far as Susa.

Peak times over the course of the next few years will see seven TBMs in operation at any one time, carrying out 75% of base tunnel excavation works in both Italy and France.

A delivery ceremony for the TBM was attended by Daniel Bursaux, Chairman, and Maurizio Bufalini, CEO of TELT – the binational Italian-French company responsible for the construction and future management of the cross-border section of the Turin–Lyon line – representatives of the UXT consortium, and construction supervision consortium IS2P (FS Engineering, ARX, Systra, Setec). Also present were Pietro Falcone, Italian Consul in Freiburg, and Elena Chiorino, Vice-President of the Piedmont Region. Remote speeches were delivered by Matteo Salvini, Italian Deputy Prime Minister and Minister of Infrastructure and Transport, and Philippe Tabarot, French Minister of Transport.

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The TBM itself measures 235 metres in length, and consists of a cutterhead with a diameter of 10.16 metres and an external shield protecting both workers and the machine itself during excavation. It is equipped with 13 motors capable, and is capable of generating a total power output of 4,550kW, advancing approximately 10 metres per day by means of hydraulic cylinders that push against installed concrete segments.

In order to meet specific requirements of this section of the tunnel, a dual-mode TBM has been designed that is capable of operating in both hard rock (open mode) and water-bearing loose ground (closed mode). During closed-mode, excavated material is removed by using a closed slurry circuit instead of a conveyor belt. This system also includes a crusher that reduces the size of all excavated rocks, as well as a pipeline that transports a mixture of water, bentonite and crushed material to the surface.

The TBM is also equipped with a hyperbaric compression & decompression chamber, which allows human intervention in pressurised environments when necessary, as well as a pressurised shuttle system that allows personnel to exit safely and undergo gradual decompression during longer interventions without interrupting typical construction activities.