Gotthard Base Tunnel

The Gotthard Base Tunnel is a railway tunnel through the Alps in Switzerland. It opened in June 2016 and full service began the following December. With a route length of 57.09 km (35.47 mi), it is the world's longest railway and deepest traffic tunnel and the first flat, low-level route through the Alps. Located at the heart of the Gotthard axis, it is the third tunnel to connect the cantons of Uri and Ticino, after the Gotthard Tunnel and the Gotthard Road Tunnel. The GBT consists of a large complex with, at its core, two single-track tunnels connecting Erstfeld (Uri) with Giornico (Ticino) and passing below Sedrun (Grisons). It is part of the New Railway Link through the Alps (NRLA) project, which also includes the Ceneri Base Tunnel further south (opened on 3 September 2020) and the Lötschberg Base Tunnel on the other main north–south axis. It is referred to as a "base tunnel" since it bypasses most of the existing vertex line, the Gotthard railway line, a winding mountain route opened in 1882 across the Saint-Gotthard Massif, which was operating at its capacity before the opening of the GBT. The new base tunnel establishes a direct route usable by high-speed rail and heavy freight trains.