THE world's fastest train hit its first speed bump in the form of a disobedient smoker less than a week after it began running in southern China.

A cigarette triggered an alarm that forced a two-and-a-half hour stoppage, nearly as long as the train takes to cover the 1100km distance between Guangzhou, capital of Guangdong province, and the central city of Wuhan.

Managers of the bullet train, which debuted on Saturday, were unable to catch the smoker who fled the scene before the alarm sounded, the official Xinhua news agency reported.

"Smoking is strictly forbidden on the Wuhan-Guangzhou high-speed train, even in the toilet," a spokesman with the Guangzhou Railway Group Corporation said.

"It could trigger the alarm and even cause equipment failures."

The train was in the Guangzhou rail station when it was delayed and had not yet begun its 350km/h journey, Xinhua added.

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