Officials in the southwestern Chinese city of Kunming said on Thursday that a train struck a group of railway workers, killing 11 people and injuring two others.

The officials said the train, which was testing earthquake-detection equipment, hit the workers on a curved section of track at the Lvyang Town railway station.

They added in a statement that the station in Yunnan province has resumed normal operations, while authorities have opened an investigation into the cause of the accident.

China has the world’s largest railway network, stretching more than 160,000 kilometres (100,000 miles) and carrying billions of passengers each year.