The world’s longest tunnel at present is Switzerland’s Gotthard Base Tunnel, which is 57 km long. However, China is now planning to build an even longer tunnel that could change the way people travel between two major cities. Known as the Bohai Strait Tunnel, the project will stretch nearly 76 miles and is expected to reduce a six-hour journey to just 40 minutes.
The tunnel will be built beneath the Bohai Strait and will connect the cities of Dalian and Yantai. The estimated cost of the project is more than £20 billion, making it one of China’s most ambitious infrastructure plans. The tunnel will include two parallel passages for high-speed trains, with trains running at speeds of over 150 miles per hour. This is significantly faster than Eurostar trains, which travel at around 100 miles per hour through the Channel Tunnel.
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Undersea tunnel longer than any before
According to project planners, the Bohai Strait Tunnel could be more than 75 miles long, with around 56 miles built entirely under the sea. This underwater section alone will be longer than the combined submerged lengths of the Channel Tunnel and Japan’s Seikan Tunnel.
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Once completed, the tunnel will cut travel time between Dalian and Yantai by nearly 90 per cent. At present, the fastest way to travel between the two cities is the Bohai Train Ferry, which takes six to eight hours to cross the strait.
Timeline, safety features and economic benefits
The project is estimated to cost 220 billion yuan (over £23.3 billion) and is expected to take 10 to 15 years to complete. Even smaller tunnel projects in the past have taken several years to finish.
Officials have said the tunnel will be equipped with advanced safety systems, including improved ventilation, waterproofing, structural sensors and emergency exits. These features are designed to protect passengers while passing through earthquake-prone areas between the Liaodong and Shandong peninsulas.
Both cities are important economic hubs and the tunnel is expected to boost trade, travel and industrial growth in the region.