China has completed a major underwater railway tunnel beneath the Yangtze River, marking step in the expansion of its high-speed rail network. The 14.25-km Chongming-Taicang Yangtze River tunnel includes an 11.18-km section running under the river. Once operational, it is expected to support bullet train movement at speeds of up to 350 kmph. The project links Chongming District in Shanghai with Taicang in Jiangsu province and is among the most advanced underwater rail tunnels in the world.
Project Overview
The tunnel is part of a broader high-speed rail corridor in eastern China. It was built using the shield tunnelling machine named Linghang. The underwater section required advanced engineering to manage pressure, stability, and alignment beneath the riverbed. The project reflects China’s continued investment in large-scale transport infrastructure and inter-city connectivity.
Engineering Significance
The tunnel is designed for high-speed rail operations, which demands strict safety and precision standards. Its long underwater stretch makes it a notable civil engineering achievement. Such projects require careful control of groundwater, soil conditions, and tunnel lining strength. The structure also supports smoother travel between major economic zones in the Yangtze River Delta.
CR450 Bullet Train Development
The tunnel is linked to China’s next-generation CR450 bullet train programme. The CR450 has been presented as the world’s fastest bullet train in trials. It has recorded a top speed of 453 kmph and a relative passing speed of 896 kmph. Its design includes a longer nose cone, reduced air resistance, lowered height, and lighter weight. These features improve speed and energy efficiency.
Broader Transport Context
China continues to expand its high-speed rail system as part of long-term infrastructure modernisation. The Yangtze underwater tunnel and the CR450 project together show the country’s focus on faster regional mobility, advanced rail technology, and engineering innovation in transport networks.
Last Modified: April 27, 2026