17-Minute Commute Between Chongming & Baoshan: Cross-Yangtze Rail Tunnel Hits Milestone

Travel time between Shanghai's Chongming Island and Baoshan District could be cut to just 17 minutes once a cross-Yangtze River rail tunnel is completed, with the project reaching a major construction milestone.

The tunnel, officially named the Chongming-Taicang (Chongtai) Yangtze River Tunnel, is a critical section of the Shanghai-Chongqing-Chengdu High-Speed Railway.

Its tunnel boring machine – over 15 meters in diameter, fully developed in China and the world's largest of its kind – passed the 10-kilometer excavation mark on Tuesday, a first for equipment of that size, according to project manager Xu Weiqing.

Spanning a total of 14.25 kilometers, the tunnel connects Shanghai's Chongming Island with Taicang City in neighboring Jiangsu Province. Of that length, 13.2 kilometers run underground beneath the Yangtze River.

It will enable high-speed trains to cross the Yangtze without slowing down, drastically reducing travel times between Chongming, Taicang and Baoshan. Railway stations are currently under construction in both Chongming and Baoshan to link up with the tunnel.

Xu said the construction pace is exceptional for high-speed rail tunnels. The machine completed the underground segment in fewer than 20 months, navigating embankments, shipping lanes and the river's deepest point – roughly 89 meters below the surface.

The machine is now less than 1 kilometer from the Yangtze River's southern bank, and the project is entering one of its most challenging phases as it nears completion. Engineers said preparations are underway in Taicang to receive the tunnel, with related equipment already being installed and tested on site.

Once completed, the Chongtai tunnel is expected to rank among the world's longest single-bore high-speed rail tunnels. It will also boast the highest design speed for an underwater rail tunnel and the deepest riverbed rail crossing on the Yangtze River.

The eastern section of the Shanghai-Chongqing-Chengdu High-Speed Railway, which connects Shanghai, Nanjing in Jiangsu, and Hefei in Anhui, is scheduled to open by the end of 2029 and is expected to play a key role in improving rail connectivity across the Yangtze River Delta region.