14km Underwater Rail Shortens Shanghai-Chengdu Travel Time by 5. 5 Hours

The world's largest diameter high-speed rail tunnel boring machine (a shield TBM), independently developed by China and named "Linghang Hao" (Navigator), has successfully completed 11.18 kilometers of tunneling beneath the Yangtze River.

Since setting off from Shanghai's Chongming Island on April 29, 2024, the machine has been steadily tunneling for 23 months.

So what does this mean?

It's nothing short of a miracle in underwater high-speed rail construction – after all, a full 14 kilometers of the line runs beneath the river!

What You Need to Know:

1. Travel time between Shanghai and Chengdu, capital of southwest China's Sichuan Province, will be cut by 5.5 hours.
2. Starting from Shanghai, the route will link three major city clusters across a stretch of about 2,000 kilometers.
3. More than 20 smaller cities along the line will, for the first time, enter the era of 350km/h high-speed rail.
4. Once completed and operational, it will enable high-speed trains to cross the Yangtze River without slowing down.
5. It is being operated at a depth of 89 meters beneath the riverbed.

The Chongtai Yangtze River Tunnel (from Chongming Island to Taicang), with a total length of 14.25 kilometers, involves an investment exceeding 500 billion yuan (US$72.3 billion). It is expected to drive nearly 1.5 trillion yuan in added value across upstream and downstream industries.

The shield TBM are highly complex and technologically advanced systems. Using a rotating cutterhead, the machine excavates rock and soil at the tunnel face while simultaneously installing pre-made segments to form the tunnel walls, creating a complete tunnel underground as it advances.

A single shield TBM consists of more than 20,000 components and is widely regarded as a key indicator of a country's manufacturing capabilities. Standing inside this machine, you would find it as tall as a five-story building.

At the same time, it has set a world record: For the first time, a 15-meter-class large-diameter shield TBM has achieved a continuous single-drive advance of 11,182 meters – completing an unprecedented "ultra-long-distance run" beneath the river.

Back in 1997, China imported its first two shield TBMs from Germany at a cost of nearly 700 million yuan. Before 2006, the country had imported more than 130 shield TBMs, spending over 10 billion yuan in total.

But things have changed.

Today, Chinese shield TBMs command around 70 percent of the global market share, with products exported to more than 40 countries and regions across five continents.