What’s the longest railway tunnel in the world? © iStock

What’s the longest railway tunnel in the world?

The race is on, but who will win? These countries are steaming ahead.

Asked by: Rob Haynes, London


Line 3 of the Guangzhou Metro in China has a main branch line that is 60.4km (37.5 miles) long. If you discount urban metro lines, the title currently goes to the Seikan Tunnel in Japan, which connects the islands of Hokkaido and Honshu. This is 53.85km (33.5 miles) long and is also the deepest rail tunnel in the world, running 100m below the seabed. This record will be beaten next year when the 57.1km (35.5 mile) Gotthard Base Tunnel through the Swiss Alps opens. And both will be eclipsed by the 123km (76.4 mile) tunnel planned to cross the Bohai Strait in China by 2023.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.