A 20,000-metric-ton heavy-haul train, No 73003, loaded with thermal coal, departed from Hudong Railway Station in Datong, Shanxi province, at 9:50 am on Thursday, marking a new milestone in freight volume for a single railway line globally.

So far, the cumulative freight volume of the Datong-Qinhuangdao Railway has exceeded 9 billion tons.

The 653-kilometer railway runs from Datong to Qinhuangdao in Hebei province. The railway provides coal to 26 provinces, municipalities and autonomous regions, as well as more than 300 power plants and 6,000 mining enterprises.

It handles one-fifth of the country's railway coal transport and has become a vital energy link connecting coal-rich regions such as Shanxi and Shaanxi provinces, and the Inner Mongolia autonomous region.

The railway has continually deepened independent innovation and made equipment upgrades since the first phase of the project opened in 1988. The whole line opened to traffic in 1992.

Since its operation, the railway has continuously broken annual freight records in response to national economic development needs. As the most important railway in the country for coal transport, its annual freight volume increased from over 20 million tons in 1989 to a peak of 451 million tons in 2018.

The cumulative freight volume reached 1 billion tons for the first time in 2004, the second billion in 2008 and the third billion in 2011.

Since 2012, the railway has added another billion tons every 2.5 years. Currently, the railway has an annual transportation capacity of 450 million tons, providing robust support for national energy security and economic and social development.

"We have established a complete system featuring 'matching of production, transportation and demand', 'coordination of collection and distribution', and 'integration of speed, mobility and heaviness' with independent intellectual property rights," said Zhang Wei, director of Hudong Railway Station. "The system has set and maintained several railway world records, including the highest density of heavy-haul trains operating on a single heavy-haul railway, the largest transportation capacity and the best transportation efficiency."

"It has led China's heavy-haul transportation to the forefront of the world," he said. "Meanwhile, the transportation volume of more than 9 billion tons also reflects the vigorous vitality of China's economic and social development."

The system has been applied to other heavy-haul railways, such as the Watang-Rizhao Railway. On April 2, 2014, a nearly 4-kilometer-long 30,000-ton heavy-haul train was successfully tested on the Datong-Qinhuangdao Railway, making China one of the few countries in the world mastering 30,000-ton railway heavy-haul technology.

In February 2020, a new generation of wireless synchronized control systems for heavy-haul trains was successfully tested on the railway. Breakthrough advancements have also been made in research on auxiliary driving for heavy-haul trains and new controllable end-of-train devices in recent years.

Over the past decades, the railway has undergone three major capacity expansion and renovation projects, with continuous upgrades to infrastructure and equipment. The railway tracks have been updated to the fifth generation, achieving high performance, longevity and strength. "Digital vehicle maintenance system has increased overall maintenance efficiency by 20 percent, while continuously enhancing the safety and efficiency of railway transportation," said Yu Wenbin, Party secretary of the train's wheel set workshop at the station.

Contact the writers at zhouhuiying@chinadaily.com.cn