What is the world’s longest railway tunnel, opened in Switzerland in 2016?

The world’s longest railway tunnel, opened in Switzerland in 2016, is the Gotthard Base Tunnel.

The Gotthard Base Tunnel runs for 57.09 kilometres beneath the Swiss Alps between Erstfeld and Bodio. It opened for regular passenger and freight service on 11 December 2016. By crossing the Alps at a comparatively low elevation, it created a flatter north–south route and reduced the need for trains to climb steep mountain grades.

The tunnel consists of two parallel single-track tubes connected by cross-passages. Construction took about 17 years and involved boring through difficult rock formations at great depth. It forms the central part of the New Railway Link through the Alps, a major Swiss transport project intended to shift freight from roads to rail.

The Channel Tunnel is often mentioned alongside it, but the Channel Tunnel is shorter and passes beneath the English Channel. Japan’s Seikan Tunnel is also a railway tunnel, but it is shorter than Gotthard. The Gotthard title refers to railway-tunnel length, not the longest tunnel of every possible type.