Construction sites

Saint Martin de la Porte
Saint Martin de la Porte

12 construction sites between France and Italy: 9 are civil engineering works and 3 related activities

Active or completed construction sites
The base tunnel

The construction sites for the Lyon-Turin base tunnel are active in the two countries. The base tunnel, the main work for the cross-border section, is a complex infrastructure, consisting of: two parallel, 57.5-km-long, tubes to accommodate the tracks for the passage of freight and passenger trains; 204 safety bypasses and 4 declines.

In addition to the underground work, TELT manages and coordinates the surface sites, both in Italy and France, which ensure the connection to the respective national lines through the new international stations.

The construction sites are checked around the clock via a series of internal and external monitoring stations that measure 135 different environmental parameters (water, dust, asbestos, radon, etc.). These measurements are carried out under the supervision of national control bodies, to ensure the respect of the territory and the health of workers and citizens.


Progress: december 2023

35 Km dug
Digging and constructions 21.6%
Cantierizzazione 2018
The access adits

The access adits are three on the French side – Villarodin-Bourget/Modane, La Praz and Saint-Martin-La-Porte – and one is in Chiomonte on the Italian side; in total, the access adits constitute approximately 18 km of tunnels that will be used both for the construction and maintenance of the base tunnel and as emergency accesses.

More specifically, the access adits have represented 4 different ways to ascertain and evaluate the main geological obstacles and to develop the most efficient solutions for the construction of the base tunnel: the re-use of excavation materials at the Villarodin-Bourget/Modane construction site; water management in tunnels at La Praz; rock convergence at Saint-Martin-la-Porte; and mechanised excavation at Chiomonte.

In this phase, the access adits serve as access routes to the base tunnel construction site. Once the tunnel is operational, they will serve as maintenance access tunnels and as safety accesses.