A staff worker directs passengers at Guomao Subway Station on Line 10 of the capital’s underground network on Wednesday. Security and maintenance checks on the subways has been stepped up after a tragic accident on Tuesday morning. [Photo provided to China Daily]

BEIJING - All 1,331 escalators and elevators at subway stations citywide have been checked for faults, transport authorities assured on Wednesday, in an effort to ease fears following an accident that killed a teenager.

The use of 257 escalators made by OTIS, the company that installed the machinery that malfunctioned at Line 4's Beijing Zoo Station on Tuesday morning, has been suspended until after detailed safety checks, transport commission officials said at a news conference.

Zhang Wenqiang, who works for the commission, said Beijing's quality supervision bureau is poised to launch an investigation of OTIS escalators and "will demand a product recall if necessary".

Beijing MTR Corporation, which operates Line 4, and OTIS Elevator Company have both issued apologies on their websites since the accident, which happened at 9:35 am when a crowded rising escalator suddenly reversed.

A total of 30 people were injured, while a 13-year-old boy surnamed Wu from East China's Anhui province was crushed to death.

The youngster was with his father and sister on their way to Beijing Zoo when the accident happened. His father suffered a spinal injury, while his sister received a head wound. Both are being treated at Peking University People's Hospital.

New Express reporters described seeing Wu's father at the hospital in a wheelchair, bare-footed and with blood on his T-shirt and pants. They quoted him only as saying: "I miss my son."

Yang Ling, spokeswoman for Beijing MTR Corporation, said 24 of the injured people were discharged from hospital on Wednesday, while the conditions of six others are stable.

She said her company will cover the cost of transportation and accommodation for victims, while the amount of compensation is still to be negotiated.

Following an investigation, Beijing's quality supervision bureau put the cause of the accident down to a malfunction in the escalator's forward lifting mechanism, which resulted in the chains breaking and the steps falling downwards.

A systematic examination of all 14,000 or so escalators and moving walkways in Beijing will be conducted, the bureau pledged in a statement.

Beijing has the third busiest subway network in the world. Line 4 was put into trial operation on Sept 28, 2009. The Beijing MTR Cooperation, established in 2006, was the first joint venture in China's rail transit sector.

Meanwhile, authorities say a nationwide safety check is being launched to catch similar safety problems, with quality control chiefs in Shanghai and Shenzhen ordering inspections at airports, department stores, subway stations and other locations where escalators are used extensively.