This article is more than 9 years old

This article is more than 9 years old

A teenage boy has been killed and dozens of people were injured when they were thrown off an escalator that suddenly changed direction in a busy Beijing subway station.

The accident happened on Tuesday on one of the capital's newest lines, prompting concerns that China's recent rush to build public transport networks may have led to declining safety standards.

The 13-year-old boy who died was on his way to Beijing zoo when the up escalator suddenly went into reverse, according to domestic media reports.

Witnesses described a strange grinding noise from the shifting gears and then a tumult in which riders at the top of the escalator fell to the bottom in less than two seconds.

The boy and the other riders were thrown down the metal stairs and into a heap at the bottom. Twenty-eight people were taken to hospital, including the dead boy's father and sister. Two were described as being in a serious condition.

Station staff declined to comment, but the railway operator put out a brief online statement expressing remorse for the death and extending "apologies and sympathy to the injured and their relatives".

It said an investigation was under way into the cause of the breakdown at Beijing zoo station. The government has ordered checks on elevators at other stations.

The capital's subway system opened in 1969 and has expanded rapidly in the past few years to become one of the five longest networks in the world with more than 170 stations and 250 miles of track.

Line 4 is one of the most modern. Completed in 2009, it connects the university district to the south of the city.

Commuters were horrified at the safety failure. "This is unbelievable. This is the most basic thing and they can't even do it well. I am very disappointed by Beijing's public transportation system," said Olivia Li, a student at Renmin University who often takes Line 4.

Additional reporting by Cheng Han