In December 2025, China ran seven 5,000-ton coal trains across Inner Mongolia as a formation heavier than three Eiffel Towers combined, without physically connecting them; engineers believe it could boost rail capacity by over 50% without new tracks

In December 2025, China pulled off a railway experiment that sounds almost like something from a futuristic transport system: seven freight trains, each weighing 5,000 tons, ran on the same line in a compact formation without being connected by mechanical couplings, synchronizing their acceleration and braking exclusively through an intelligent wireless control system.

The test, conducted on the Baoshen railway in Inner Mongolia, brought the combined weight of the seven trains to 35,000 tons, which is equivalent to more than “three Eiffel Towers.”

Instead of physically connecting the trains, engineers used wireless communication and precise control technology to make the separate train units behave like a single coordinated formation.


China Energy Investment Corporation (CHN Energy) said on December 8 that it had successfully completed the world’s first 35,000-ton heavy-haul group train system test at the south yard of Wanshuiquan South Station on the Baoshen Railway in Inner Mongolia Autonomous Region.

The experiment points to a potentially important question for heavy-freight rail: Can railways move more cargo without building more tracks?

China ran seven 5,000-ton trains without physically coupling them

Traditional heavy-haul freight trains are mechanically connected, meaning the locomotives and wagons form a single physical train.

China’s latest test took a different approach. Seven separate 5,000-ton freight trains were brought together virtually using wireless communication. The trains, positioned at four stations, Nalingoumen, Shabazi, Guannianfang and Dalate North, formed what CHN energy described as ‘virtual coupling.’

The trains could then operate in close-following mode while remaining physically separate. The key was keeping their movements synchronized.

How exactly does “virtual coupling” work?

The technology essentially creates a digital connection between trains that have no physical connection. The system continuously monitors and processes information, including the relative speed between trains and their absolute distance from points on the line. Two-way communication between trains and ground infrastructure allows the control system to coordinate their movements in real time, as explained on the railway pro webpage.

That means one train does not simply travel behind another and react manually. The system is designed to coordinate acceleration and braking across the formation while maintaining safe spacing.

In the latest trial, the trains operated together at speeds of up to 60 km/h. Test data showed the following distances of 1,091 meters between 5,000-ton loaded trains and about 943 meters between 5,000-ton empty trains, demonstrating the system’s ability to maintain stable spacing under heavy-haul conditions.

The trains can group together and separate automatically

One of the more unusual aspects of the test was that the virtual formation was not simply created and then left intact. The seven trains were gradually brought into the virtual group as they moved along the Baoshen line. Once formed, they continued toward Wanshuiquan South in coordinated close-following mode.

At the terminal station, the system demonstrated another capability: automatic separation.

The trains separated from the virtual formation and entered the station individually, while the wireless control system continued to coordinate their movements.

Why does this matter for China’s freight railways?

The experiment is particularly relevant to heavy-haul routes, where more freight volumes can create pressure on existing railway infrastructure.

Building additional tracks is expensive and can take years. Increasing the amount of freight that an existing line can handle, therefore, offers another route to expanding capacity.

CCTV and Chinese technical reporting have said the technology could increase freight line capacity by more than 50% without major infrastructure investment.

That possibility is significant for routes such as the Baoshen Railway, a major corridor for coal transportation between Shenmu and Ordos.

Instead of treating every freight train as an entirely independent movement, a virtual convoy could allow several trains to occupy the same operational window while remaining physically separate.

The idea has been years in development

The 35,000-ton trial was not a one-off demonstration. The test formed part of the Technology Research and Application of Heavy-Haul Group Operation Control Systems project, jointly undertaken by China Shenhua and Baoshen Railway under CHN Energy, together with the CRSC Research & Design Institute Group Co., Ltd.

The project began in 2022 and has since tested multiple operating scenarios, including single-locomotive runs, 5,000-ton loaded and empty trains and 10,000-ton empty trains.