Construction crews are laying the first rails for the Shanghai-Nanjing section of the Shanghai-Chongqing-Chengdu high-speed railway. (Provided to chinadaily.com.cn)

The first rails for the Shanghai-Nanjing section of the Shanghai-Chongqing-Chengdu high-speed railway were laid on Thursday, marking a milestone for a project designed to further integrate eastern China's economic powerhouse region.

At the Tongtaiyang bridge construction site in Nantong, Jiangsu province, automated laying machines pulled out and positioned the first pair of 500-meter steel rails, launching full-line track installation along the line.

"The commencement of track-laying operations lays a solid foundation for completing installation along the entire corridor," said Song Ming, track-laying manager of the project from China Railway First Group Co.

Spanning 422.9 kilometers with a designed speed of 350 kilometers per hour, the line serves a vital link along the Yangtze River corridor within China's "eight vertical and eight horizontal" high-speed rail network.

Starting at the newly built Shanghai Baoshan station, the line passes through the Jiangsu cities of Suzhou, Nantong, Taizhou and Yangzhou before terminating at Nanjing north station. It will feature 12 stations in total.

The track-laying work will require laying approximately 781.5 kilometers of mainline track, installing 283 sets of turnouts, and placing 484,600 cubic meters of ballast.

To enhance efficiency, an intelligent multifunctional dual-line rail-laying system was deployed, which is capable of laying two tracks simultaneously without requiring equipment returns or line switches.