A new tunnel boring machine presented on the Lyon-Turin construction site

A 2.300-tonne behemoth with a power of 8.100 kW, 180 metres long and more than 10 metres in diameter: the tunnel boring machine, delivered by the German company Herrenknecht, is currently being assembled in Saint-Julien-Mont-Denis in Savoie.

Its mission: to dig 9 kilometers, at an average of 350 meters per month, in the northern gallery, "parallel to that already carried out by the tunnel boring machine Federica in the southern gallery, between Saint-Martin-La-Porte and La Praz", explains TELT.

"What is expected are advancement speeds of reasonably between ten and fifteen metres per day, or even more, depending on the sections, depending on the geological conditions. These advancement speeds are significantly higher than those using the conventional method," Emmanuel Humbert, construction director for France at TELT, explained to journalists.

The machines were built specifically for the site, dismantled and transported to the site, "pre-assembled outside and now assembled underground to start digging soon," he explained.

"The first steps will probably take place after the summer," added Mr. Humbert.

In addition to the machine delivered, of the seven tunnel boring machines intended to dig 75% of the base tunnel, four have been validated in the factory, and one ordered.

Two tunnel boring machines had already been used earlier, in the first phases of work.

Excavation of the base tunnel, which connects France and Italy for the future Lyon-Turin rail link, began in 2016 and 15,7 km have already been dug.

In total, as of January, 40 km have been excavated out of the 164 km planned for the entire project, consisting of two parallel railway tunnels, ramps and safety branches, according to TELT data.

For this project, 11 sites are planned for open-air and underground work, including four sites for the excavation of the base tunnel.

Currently some 2.800 people work there, a number that will reach 4.000 "at the peak of the work".

The company is aiming for completion in 2033.

At the end of 2024, the French State officially chose the so-called "large gauge" route for French access routes to the entrance to the cross-border tunnel which passes under Mont-Cenis.