# China undersea high-speed rail infrastructure development

> Live situation record from CLSTR: https://clstr.news/situations/china-undersea-high-speed-rail-infrastructure-development
> Updated: 2026-09-04T06:00:00.000Z. Sources: 4. Developments: 2.

China is advancing major undersea and underwater high-speed rail infrastructure projects. In Nanjing, the production of the ‘Linghang’ tunnel boring machine (TBM) was completed for a project involving a 20.4-kilometer tunnel beneath the Yangtze River. This project features a segment reaching depths of 107 meters, making it the deepest and highest-pressure railway shield tunnel constructed along the river.

Simultaneously, the Jintang Undersea Tunnel, intended to connect Ningbo and Zhoushan beneath the East China Sea, has completed its underground construction phase. As the world’s longest undersea high-speed rail tunnel, the project utilizes advanced TBMs to manage complex seabed geology and seismic risks to facilitate regional economic integration.

## Timeline

### 2026-09-04: Jintang Undersea Tunnel completes underground construction phase

China has completed the underground construction phase of the Jintang Undersea Tunnel, the world’s longest undersea high-speed rail tunnel, linking Ningbo and Zhoushan.

2 sources. https://clstr.news/cluster/jintang-undersea-tunnel-completes-underground-construction-phase

### 2026-08-31: China completes massive TBM for Yangtze River high-speed rail tunnel

China has completed a massive 145-meter tunnel boring machine to build a high-speed railway tunnel under the Yangtze River in Nanjing, reaching depths of 107 meters.

2 sources. https://clstr.news/cluster/china-completes-massive-tbm-for-yangtze-river-high-speed-rail-tunnel

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Cite as: China undersea high-speed rail infrastructure development. CLSTR, https://clstr.news/situations/china-undersea-high-speed-rail-infrastructure-development