A domestically manufactured 14-meter-class super-large diameter shield tunneling machine, named "Pioneer" rolled off the production line on July 17, 2026. Photo: VCG

A domestically manufactured 14-meter-class super-large diameter shield tunneling machine, named "Pioneer" rolled off the production line on Friday, the Xinhua News Agency reported, citing its developer.

The 14.02-meter-diameter machine, jointly built by China Railway 14th Bureau Group and China Railway Construction Heavy Industry Co, will be used to bore the Taihu Lake crossing section of the Wuxi-Yixing intercity railway (the S2 Line) in East China's Jiangsu Province, according to China Railway Construction Corporation (CRCC).

The S2 Line, which links the cities of Wuxi and Yixing, is a key project in the effort to build a "half-hour commuter circle" between the two cities and boost the integrated development of the Yangtze River Delta region.

With a total length of about 61 kilometers and a design speed of 160 kilometers per hour, the line's Taihu Lake tunnel, stretching 21.6 km, is a crucial part of the project. It will be constructed in five sections using four 14-meter-class super-large diameter shield machines, making it the country's first ultra-large diameter shield tunnel beneath Taihu Lake.

Tian Zhaoping, the shield project manager from China Railway 14th Bureau Group, said the Pioneer features a pressurized composite cutterhead design with various cutter types, including disc cutters, scraper cutters and overcutters, which can be flexibly replaced according to the geological conditions.

The machine is also equipped with a high-precision guidance system, an intelligent excavation management system, a high-power crusher system, and a synchronous single-liquid thick slurry grouting system.
  
Once completed, the S2 Line will connect major transportation hubs such as Sunan Shuofang International Airport, Wuxi Railway Station and Yixing high-speed railway station. 

Global Times