Summary：Construction began on the Chongqing Yangtze River tunnel of the Chongqing-Hunan high-speed railway on Wednesday, ra...

Construction began on the Chongqing Yangtze River tunnel of the Chongqing-Hunan high-speed railway on Wednesday, railway developer Yuqian Railway Co announced.

The company said it will be China's longest underwater tunnel for high-speed rail.

This tunnel, which will run through the Yuzhong and Nanan districts of Chongqing, will be 11.9 kilometers long and have a maximum depth of 330 meters. Trains will run up to 120 km per hour.

The line is a major part of the Xiamen-Chongqing High-speed Railway in a network of eight horizontal and eight vertical railway lines depicted in the nation's medium- and long-term rail development plan.

The 295-kilometer Chongqing section, which is currently under construction, is projected to begin operations in June 2025 and will be the first mountain railway in the municipality to run at a speed of 350 km per hour.