Passengers buy train tickets by TVM (Ticket Vending Machine) at Qingdao Railway Station in Qingdao, east China's Shandong Province, April 30, 2014. The four-day period of Labor Day travel peak began on Wednesday. National railways are expected to receive 36,400,000 passengers from April 30 to May 3, 2014. (Xinhua/Wang Haibin)