Passengers walk down stairs to board trains at Yinchuan Railway station in Yinchuan, Northwest China's Ningxia Hui autonomous region, on July 1, 2012. China's summer travel peak which starts on July 1 and ends on August 31 is estimated to transport 372 million people, 21.6 million more than last year, with a daily volume of 6 million. [Photo/Xinhua]