The Xindading mountain tunnel of the Fuzhou-Xiamen High-speed Railway in East China's Fujian province completes construction on July 12. [Photo/CFP]

The Xindading mountain tunnel of the Fuzhou-Xiamen High-speed Railway in East China's Fujian province was completed on July 12, after 27 months of construction.

Located in Minhou county in Fuzhou, the Xindading mountain tunnel is a double-track high-speed rail tunnel with a total length of 4,054 meters and a maximum buried depth of 187.5 meters.

Officials of China Railway Nanchang Group said that the complex geological conditions and poor construction environment brought difficulties to the tunnel's construction process. They used nearly 20 informatization methods, such as surrounding rock monitoring and measuring, to ensure construction safety and quality.

The Fuzhou-Xiamen High-speed Railway is China's first cross-sea high-speed train, with a design speed of 350 kilometers per hour.

The 277.42-kilometer railway line will pass major cities in Fujian province, including Fuzhou, the provincial capital, Putian, Quanzhou, Xiamen, and Zhangzhou.

The railway is expected to be put into service in 2023. It will shorten the travel time from Fuzhou to Xiamen by one hour, form a half-hour traffic circle among Xiamen, Zhangzhou, and Quanzhou, as well as boost the rapid development of the southeast coastal city cluster.