The Caiyuanba Yangtze River Railway Tunnel in Chongqing will form a key section in a new line linking the megacity with the southeast coast
2-MIN READ2-MIN ListenAlice LiPublished: 8:00pm, 25 Jul 2026China finished the first high-speed railway tunnel under the Yangtze River on Friday, marking a major step forward in the construction of a line that will one day connect the inland of the country with the coast.
The 11.9km (7.4-mile) Caiyuanba Yangtze River Railway Tunnel links two districts in Chongqing and will be a key link in a high-speed line between two key hubs in the southwestern megacity and Xiamen in the southeastern province of Fujian.
The project had to overcome the challenges posed by the city’s geography and dense urban landscapes as it tunnelled beneath mountains, residential areas and riverbeds.
The constructor, China Railway 14th Bureau Group, used a customised boring machine – named Changjiang, the Chinese name for the Yangtze – which can withstand high water pressure while cutting through alternating rock layers deep under the riverbed, state news agency Xinhua reported on Saturday.
The network – formed of eight north-south and eight east-west routes – stretches as far as Gansu province in the northwest, the cities of Hong Kong and Shenzhen on the southern coast, and transport hub Harbin in the northeast.
By March, construction work on the grid was already 84 per cent complete, according to state-owned China Railway Group.
