Passengers pass by an escalator out of service in the Huaqiang Station of the Shenzhen Subway Line 4, in Shenzhen City, south China's Guangdong Province, July 10, 2011. Escalators in the subway line 4 stations were temporarily supended after an escalator suddenly ran backward at the Qinghu Station of the Shenzhen Subway Line 4 at around 9:00 p.m. (1300 GMT) Sunday. The accident caused at least two people injured. [Xinhua/Li Jianqiang]