China completes first high-speed rail tunnel under the Yangtze River

China 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…