High-speed rail in Switzerland

High-speed rail in Switzerland consists of two new lines and three new base tunnels, including the world's longest railway and deepest traffic tunnel: the Gotthard Base Tunnel whose length is 57 km (35 mi). Each of these tunnels have a technical maximum speed of 250 km/h (155 mph), which is reduced, at least in the Gotthard Base Tunnel and the Ceneri Base Tunnel, to a maximum authorized speed of 230 km/h (145 mph), for environmental and economic reasons.

Source: Wikipedia — High-speed rail in Switzerland (CC BY-SA 4.0)