Artists perform in the carriage of the first high-speed train from Xi'an, capital of northwest China's Shaanxi Province, to Chengdu, capital of southwest China's Sichuan Province, Dec. 6. 2017. High-speed rail line linking Xi'an and Chengdu went into operation Wednesday, slashing the travel time between the two cities from about 11 hours to just 4. [Photo/Xinhua]