'World's toughest railway project' set for completion in Yunnan by 2028

Construction of the Baoshan–Ruili section of the Dali–Ruili Railway in Yunnan province has made significant progress, putting the line on track for full operation by 2028, according to Guoshizhitongche, a social media account affiliated with China News Service.

Widely regarded by industry experts as the world's most challenging railway project, the Dali–Ruili Railway is the first rail line to cross the rugged Hengduan Mountains in southwestern China, it said. The 330-kilometer railway is being built in two sections: Dali–Baoshan and Baoshan–Ruili.

The 133-kilometer Dali–Baoshan section, which began construction in 2008, was completed in 2022 after 14 years of work. Several tunnels along the route, including the Dazhushan and Xiuling tunnels, each took more than a decade to complete. China Railway Engineering Group has described conditions in the Dazhushan Tunnel as extreme, citing heavy groundwater inflows and high geothermal heat. In some central sections, temperatures reached an average of 41 degrees Celsius, forcing workers to rotate shifts every three hours while operating in water-logged environments.

Construction of the Baoshan–Ruili section started in 2015 and has proven even more demanding. Its core project, the Gaoligong Mountain Tunnel, has long been considered the project's main bottleneck. Progress was slowed by complex geological conditions, including heat damage, severe soft-rock deformation, and large-scale water inflows, challenges that engineers likened to rebuilding a structure after it had collapsed.

In late January, Gao Shangjie, a senior engineer at the Mangshi transportation bureau in Dehong Dai and Jingpo autonomous prefecture, said that recent technical breakthroughs had significantly accelerated the tunnel's construction, according to the report. Based on targets set by China State Railway Group and the Yunnan provincial government, the main tunnel is expected to be fully excavated by December 2027, with the entire Dali–Ruili Railway becoming operational in 2028.

Once in service, the railway will reduce travel time between Kunming, the provincial capital, and the border city of Ruili from about nine hours to around 4.5 hours. It will also form a key segment of the China–Myanmar international railway corridor and increase transport connectivity between China and countries in Southeast and South Asia.

Chen Jie, deputy director of the Yunnan Provincial Development and Reform Commission, said Yunnan will accelerate construction of railways along its southwestern border during the 15th Five-Year Plan period (2026–2030). Additionally, the Chongqing–Kunming high-speed railway is expected to be completed within the next five years, creating a high-speed rail loop linking major urban clusters across southwestern China.