Two cargo trains collided Thursday on a railway that connects China’s top coal-producing regions and its key distribution port, potentially hindering transportation of the fuel at a time when coastal provinces are struggling with low supplies.

The crash took place around 1 p.m. at a Tianjin railyard on the Datong-Qinhuangdao line, state broadcaster CCTV reported. A video provided by the broadcaster showed a freight train hitting a parked locomotive, causing several wagons to derail and overturn. The moving train began sliding while parked at the station, according to the report.

Eleven wagons fell from the railway and no casualties have been reported, according to CCTV. Rescue and repair teams have been activated. It’s unclear how long the clean-up and disruption to transport might last.

The 653-kilometer-long (406 miles) rail line, known as Daqin, is China’s busiest freight route. It connects the coal-rich province of Shanxi to Qinhuangdao port southeast of Beijing. More than 420 million tons of coal traversed the conduit last year to be loaded on vessels that deliver the fuel to southern provinces.

Those regions, including China’s industrial powerhouse Guangdong province, are already facing tight coal supplies as imports dwindle and a resurgent virus clogs up transport of the nation’s mainstay fuel, an industry official warned Wednesday.

Daqin has already delayed its planned maintenance period twice this year and shortened it from 30 days to 20 days. It’s currently scheduled to begin May 1, instead of April 8 as originally intended, according to the China Coal Transportation and Distribution Association.