Bullet trains are seen in a station in Chengdu, southwest China's Sichuan Province, Dec. 2, 2017. High-speed trains linking Xi'an, capital of Shaanxi Province, and Chengdu, will begin operation on Dec. 6, authorities said Sunday. Tickets for the trains are available for purchase from 6 p.m. Sunday. (Xinhua/Xue Yubin)