Lyon-Turin Euralpin Tunnel

The longest railway tunnel in the world

The creation of the Lyon-Turin transalpine rail link is in line with the European Community’s ambition to develop sustainable transport infrastructures based on rail and designed to help reduce car traffic. At the heart of this new line is the construction of an exceptional structure, a 57.5 km tunnel passing under Mont-Cenis. Artelia is assisting the contracting authority (TELT) with this unique project.


Crossing the Alps over 57.5 km between Saint-Jean-de-Maurienne (France) and Susa (Italy), the TELT (Tunnel Euralpin Lyon Turin) will be the longest rail tunnel in the world. It will be the key structure in a new rail link between France and Italy, designed to carry 5 million passengers a year and almost 40 million tonnes of freight, thereby reducing road transport and the resulting pollution issues.

It is a highly complex infrastructure comprising two parallel tubes 57.5 km long, as well as more than 200 safety branches and 4 descents (access roads to the construction site, later used for maintenance). TELT has adopted an ESG approach to this project. To ensure the safety of workers and local residents, the worksites are continuously monitored by control centres that take readings of 135 environmental parameters (water, dust, asbestos, radon, etc.).

TELT has chosen Artelia to head the project management assistance consortium that is helping it to successfully complete this major project, currently scheduled for completion in 2030. Artelia is coordinating the many parties involved and carrying out various technical and regulatory studies in all the fields covered by the project (civil engineering, geology, geotechnics, railway equipment, railway operations, environment, safety, etc.).

Photo credits: TELT