The twin-bore Gotthard Base Tunnel in Switzerland is the first flat low-level route through the Alps Mountain and is situated 2.3 km deep under the Alps. It was built in 17 years by 2,400 workers, at a cost of over 12 billion dollars as a part of the AlpTransit project, also known as New Railway Link through the Alps (NRLA). The project consists of two single-track tunnels connecting Erstfeld (Uri) with Bodio (Ticino) and passing below Sedrun (Graubünden).

Main purpose of the Gotthard Base Tunnel: (i) Increase total transport capacity across the Alps, especially for freight. (ii) Shift freight volumes from road to rail to reduce fatal crashes and environmental damage caused by ever-increasing numbers of heavy lorries. (iii) Provide a faster connection between northern and southern Europe, cutting journey time for passenger trains by about an hour.