Wu Zhenjin, a worker at Harbin Railway Station in northeastern China's Heilongjiang province, was arrested in connection with Sunday's incident, the Global Times said, citing a China Business Morning Post report.
Wu, who led a railway maintenance team, allegedly disconnected 12 metres of the track, possibly out of anger at being passed over for a promotion, the paper said.
Investigators believe the perpetrator would have needed professional tools to cut the track, the report said, adding that Wu had exhibited "abnormal behaviour" after the incident.