This combo photo shows passengers boarding an old-style green train on a platform at the Genhe Railway Station in Hulun Buir, north China's Inner Mongolia Autonomous Region, on Jan. 31, 2016 (top, photo taken by Lian Zhen); and a bullet train which is about to depart from Chongqing West Station in southwest China's Chongqing, Feb. 12, 2018 (bottom, photo taken by Liu Chan). (Xinhua)