A “fog flashover” caused by trapped soot particles on a section of the Beijing-Guangzhou railway led to a one-hour outage of the system on Wednesday afternoon.
The incident took place as the G513 bullet train, which was en-route from Beijing, arrived in Xinyang East, Wuhan in central China's Hubei province.
Operations were delayed for nearly an hour, according to the Wuhan Evening News.
The Wuhan Railway Bureau released a statement later in the afternoon that said the accident was caused by haze.
Passengers posted on Sina Weibo that they had heard a loud explosion and seen sparks before the train came to a halt.
Fog flashovers, also known as “dirty flashes”, are short-circuits caused by fog-induced moisture or soot build-up on the surface of electrical equipment.
They are a common problem for railway operators everywhere but can be avoided by regular cleaning and installation of high-speed current breakers.