What is the name of the world's longest railway tunnel used by high-speed trains?

What is the name of the world’s longest railway tunnel used by high-speed trains? It is the Gotthard Base Tunnel.

Switzerland’s Gotthard Base Tunnel is the world’s longest railway tunnel, with a route length of about 57.09 kilometres. It runs beneath the Swiss Alps between Erstfeld in the canton of Uri and Giornico in Ticino, forming a low-level north–south rail route.

The tunnel is the central engineering work of Switzerland’s New Railway Link through the Alps project. Construction began in 1999, breakthrough was completed in 2011, and the tunnel opened in June 2016. Regular full service began in December 2016.

The Gotthard Base Tunnel is used by passenger and freight trains, including high-speed-capable services, although normal passenger speeds are lower than the train’s technical maximum. The tunnel’s technical limit is 250 km/h, while scheduled passenger operation is generally around 200 km/h. The Seikan Tunnel and Channel Tunnel are major competitors in length, but neither is longer than the Gotthard Base Tunnel as a railway tunnel.