A man works at a girder factory in Dushan County, southwest China's Guizhou Province, Oct. 20, 2020. Guiyang-Nanning high-speed railway is designed with a maximum speed of 350 km per hour. (Photos: Xinhua/Liu Xu)

Aerial photo shows the construction of Lali grand bridge of Guiyang-Nanning high-speed railway, in Dushan County, southwest China's Guizhou Province, Oct. 20, 2020. Guiyang-Nanning high-speed railway is designed with a maximum speed of 350 km per hour.

Aerial photo shows the construction of Yinpo River grand bridge of Guiyang-Nanning high-speed railway, in Dushan County, southwest China's Guizhou Province, Oct. 20, 2020. Guiyang-Nanning high-speed railway is designed with a maximum speed of 350 km per hour.

Aerial photo shows the Lali grand bridge of Guiyang-Nanning high-speed railway, in Dushan County, southwest China's Guizhou Province, Oct. 20, 2020. Guiyang-Nanning high-speed railway is designed with a maximum speed of 350 km per hour.

People work at a girder factory in Dushan County, southwest China's Guizhou Province, Oct. 20, 2020. Guiyang-Nanning high-speed railway is designed with a maximum speed of 350 km per hour.

Aerial photo shows the construction of Yinpo River grand bridge of Guiyang-Nanning high-speed railway, in Dushan County, southwest China's Guizhou Province, Oct. 20, 2020. Guiyang-Nanning high-speed railway is designed with a maximum speed of 350 km per hour.