Rescuers try to reinforce the walls of a tunnel, while searching for trapped workers in Shandan County of Zhangye, Northwest China's Gansu province, April 21, 2011. Twelve workers who were trapped in the collapsed railway tunnel were feared dead as rescuers have detected no signs of life at the scene Thursday afternoon. The tunnel is located along a new rail link currently being constructed between Gansu's provincial capital of Lanzhou and the city of Urumqi in the Xinjiang Uygur autonomous region. [Photo/Xinhua]