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.
"Previously, using traditional single-line track-laying equipment, a single crew could lay around 4 kilometers per day," Song said.
"Now, with the dual-line system, a single crew can complete 9 kilometers per day, while significantly reducing process steps and labor intensity."
To coordinate complex, concurrent operations, teams are using cloud-based tracking and transit management systems. These platforms monitor equipment around the clock, providing real-time dispatching and early warnings to maintain safety and keep the project on schedule.
Construction crews are also leveraging green and smart technologies, including high-power electric rail vehicles, energy-storage mobile welding units, robotic bolt fasteners and eco-friendly rail cutters.
"The robot can secure two bolts every five seconds, improving efficiency by two-thirds compared to manual labor and maintaining consistent performance," said Ou Jinping, director of the materials and equipment department of the project from the China Railway First Group.
Advanced stress-release systems, intelligent rail collision machines and high-precision inspection carts are being used to ensure the track meets strict safety and smoothness standards.
Underground works including roadbeds, bridges and tunnels have been largely completed, while station buildings and electrical systems are progressing on schedule.
Once operational, the high-speed line will ease heavy passenger traffic along the Yangtze River corridor, and help divert Shanghai-bound transit off existing coastal and Beijing-Shanghai routes.