China has successfully conducted a trial run of a railway innovation that allows freight trains to travel together in convoy without physical couplers. The test took place on Inner Mongolia’s dedicated Baoshen cargo line on 8 December 2025, which connects to Shenmu in Shaanxi province and is a major coal transport route.
The trial saw seven freight trains with a combined load of 35,000 tonnes, the equivalent of 20,000 cars or 4,000 Tyranosaurus Rexes, operate in a coordinated formation or convoy, using wireless technology instead of any mechanical connectors.
Reducing the physical distance required between separate trains running on the same line is a way to increase rail capacity while avoiding the expensive construction of new railways. This trial successfully reduced the time interval between all seven trains, reducing any risk of collision, using wireless technology to ensure they could brake and accelerate simultaneously. Doing it without physical coupling has been called “a major engineering feat” by state media reporters at China Daily and a “breakthrough system” by Interesting Engineering.
China has completed the world’s first test of a 35,000-tonne heavy-haul train group in north China’s Inner Mongolia, achieving fully synchronized operation of seven 5,000-tonne freight trains without mechanical couplers.
— China Science (@ChinaScience) December 9, 2025
Powered by a domestically developed wireless control… pic.twitter.com/8zLbtdqmZQ
The achievement follows theories published in a Mathematics journal by Central South University scientists and builds on long-term work towards this moment by China Shenhua Energy, part of China Energy Investment Corporation, and various research partners. CHN has previously tested two lighter rail convoys using the same method. At the time, it said the real-time wireless communication and advanced algorithm trials enabled it to “master group train operation control systems.”
@heytoddy_ The #world's first 35,000-tonne heavy-haul train operating without physical couplers has successfully completed a trial run in northern #China. This #milestone ♬ 原声 – Toddy
It’s all part of China’s ongoing strategy to increase freight rail capacity. China Daily reported the transport of over three billion tonnes of cargo by rail in the first three quarters of 2025 alone, while CCTV has said China’s freight rail capacity could grow by over 50% without a single new track as a result of the groundbreaking approach. That’s, of course, in addition to major expansions of Chinese rail links elsewhere, such as long-distance heavy-haul goods transport via China Railway Express connections to numerous European and Asian hubs. “Leveraging train-to-ground and train-to-train communication, the technology employs a two-dimensional control mode integrating relative speed and absolute distance, enabling dynamic close-formation operations,” CHN Energy said in a statement cited by SCMP.
The domestically developed intelligent system could also become a model for other regions or nations seeking ways to grow their long-distance freight capacity or improve safety parameters. It is being hailed as a cost and time-efficient innovation that requires almost zero large-scale infrastructure work.
