A bullet train is seen at Jianmenguan Station of Xi'an-Chengdu high-speed railway in Guangyuan, southwest China's Sichuan Province, Nov. 25, 2017. The Xi'an-Chengdu line is China's first rail route to run through the Qinling Mountains, which are the natural boundary between north and south China. It will begin operation on Dec. 6. [Photo/Xinhua]