A train runs past the bridge over Yachi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province, Dec. 2, 2019. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

A train runs past the bridge over Yachi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province, Dec. 2, 2019. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

A train runs past the bridge over Yachi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province, Dec. 2, 2019. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

Aerial photo taken on Dec. 2, 2019 shows a train running past the bridge over Xixi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

Aerial photo taken on Dec. 2, 2019 shows a train running past the bridge over Xixi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

A train runs past the bridge over Yachi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province, Dec. 2, 2019. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

A train runs past the bridge over Yachi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province, Dec. 2, 2019. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

A train runs past the bridge over Yachi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province, Dec. 2, 2019. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)

A train runs past the bridge over Yachi River during a trial operation of Chengdu-Guiyang railway in southwest China's Guizhou Province, Dec. 2, 2019. The 650-kilometer railway is an important part of the country's high-speed rail network consisting of eight main north-south lines and eight main east-west lines, with a design speed of 250 kilometers per hour. (Xinhua/Liu Xu)