Switzerland contains the world’s longest railway tunnel, the 57.1-kilometre Gotthard Base Tunnel.
The tunnel runs beneath the Swiss Alps between Erstfeld in the canton of Uri and Bodio in Ticino. It opened fully to scheduled passenger and freight traffic on 11 December 2016, after an official inauguration earlier that year.
Two parallel single-track tubes pass through the mountains at a relatively low elevation, reducing the steep gradients and sharp curves that affected older Alpine routes. The project took roughly 17 years to build and required extensive excavation through hard rock.
The Gotthard Base Tunnel is sometimes confused with the road tunnel through the same mountain region. The older Gotthard Road Tunnel carries vehicles, whereas the base tunnel is a railway route designed to shift Alpine freight from roads to trains.