Mont d'Ambin Base Tunnel

Mont d'Ambin Base Tunnel

Cross-section of the tunnel
Overview
Status	Under construction
System	Turin–Lyon high-speed railway
Start	Maurienne, France
End	Susa Valley, Italy
Operation
Work begun	2002
Constructed	2019–present
Traffic	passenger trains and freight trains
Character	Twin tube Passenger and freight
Technical
Length	57.5 km (35.7 mi)
No. of tracks	Double track
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge
Electrified	Electrified 25 kV 50 Hz AC
Operating speed	Passenger: 220 km/h (140 mph) Freight: 100 km/h (62 mph)
Highest elevation	580 metres (1,900 ft)
Tunnel clearance	8.4 metres (28 ft)

The Mont d'Ambin Base Tunnel, also known as the Mont Cenis Base Tunnel,^[1] is the largest engineering work of the Lyon–Turin rail link project. Once completed, it will facilitate the principal high-speed rail link between Italy and France, conveying both high-speed passenger trains and rail freight between the two countries. At 57.5 kilometres (35.7 mi), that tunnel will be the longest rail tunnel in the world, ahead of the 57.1 km (35.5 mi) Gotthard Base Tunnel. It represents one third of the estimated overall cost of the project and is the only part of the line where work has started.

Crossing the Alps between the Susa Valley in Piedmont and Maurienne in Savoie.^[2] It has an estimated cost of €8 billion.^[3] During September 2016, a key agreement towards the tunnel's construction was reached by France and Italy. Three years later, competitive tenders to perform packaged elements of the construction work were sought. As of late-2022, the expected completion date for the base tunnel was 2032.^[4]