Passengers walk to board K4076 train, the first extra train for the 2016 Spring Festival travel rush from the railway station of Shenzhen, south China's Guangdong Province, to Chengdu, southwest China's Sichuan Province, on Jan. 24, 2016. Over 2.9 billion trips will be made around China during the 40-day Spring Festival travel rush, which kicked off Sunday, traffic police authorities estimated. Spring Festival, China's most important holiday centering around family reunions, will fall on Feb. 8. (Xinhua/Mao Siqian)