Mont d'Ambin Base Tunnel
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The Mont d'Ambin Base Tunnel, also known as the Mont Cenis Base Tunnel, is the largest engineering work of the Lyon–Turin rail link project. Wikipedia
Highest elevation: 580 metres (1,900 ft)
Length: 57.5 km (35.7 mi)
Operating speed: Passenger: 220 km/h (140 mph); Freight: 100 km/h (62 mph)
Status: Under construction
System: Turin–Lyon high-speed railway