The construction site measures 12 hectares and is the largest Italian construction site for the Lyon-Turin railway line.
The Chiomonte/Giaglione construction site employs more than 700 workers. Two TBMs will excavate 30 km of tunnels, including the tunnel tubes, the Maddalena 2 tunnel and the Clarea safety site. The Maddalena 1 tunnel was used to explore the mountain and will be used for maintenance and ventilation. As the largest construction site on the Lyon–Turin line in Italy, Chiomonte has been a site of strategic national interest since 2012 and will be used as the Italian access route to the base tunnel. To guarantee the safety of workers and citizens, in 2018 the CIPE approved the variant design that provides for the start of the main excavation on from Chiomonte iand not from Susa as initially planned. The site extends over 12 hectares in the municipalities of Chiomonte and Giaglione, beneath the A32 motorway viaduct.
Pictures of the construction site
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The companies at work
TELT awarded the one-billion-euro work contract to the UXT group of companies composed of Itinera (group head), Ghella and Spie Batignolles. The project management was awarded to the group of companies, composed of Italferr, Systra Italia and Pini Group SA.
What is the current status of the construction project?
Data updated in May 2025
80%
Work techniques and completed work
A total of approximately 30 km of excavation work is planned with both conventional method and TBM, depending on the geological conditions. The work includes the two base tunnel tubes, the Maddalena tunnel, the bypasses between the two tubes, the Clarea safety site and the artificial tunnel at the Susa eastern entrance. For the excavation from the Clarea safety site to Susa, the use of two dual-mode TBMs is planned; these are capable of changing their advancement mode according to the type of terrain they have to face. Between 2012 and 2017, the 7,020-m-long Maddalena exploratory tunnel was excavated by the GEA TBM to explore the Massif d’Ambin and collect all the geological, hydrogeological, geomechanical and excavation data necessary to the design of the base tunnel. Equipped with logistics niches, it now serves as an operational access point and will be used as a service, safety and ventilation tunnel.
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