Workers lay railway tracks at the construction site of the Chengdu-Guiyang railway line in Bijie, southwest China's Guizhou Province, Oct. 10, 2018. The track laying work of the Yunnan-Guizhou section of the Chengdu-Guiyang railway line started on Wednesday. (Xinhua/Liu Xu)

Aerial photo shows workers laying railway tracks at the construction site of the Chengdu-Guiyang railway line in Bijie, southwest China's Guizhou Province, Oct. 10, 2018. The track laying work of the Yunnan-Guizhou section of the Chengdu-Guiyang railway line started on Wednesday. (Xinhua/Liu Xu)

Workers lay railway tracks at the construction site of the Chengdu-Guiyang railway line in Bijie, southwest China's Guizhou Province, Oct. 10, 2018. The track laying work of the Yunnan-Guizhou section of the Chengdu-Guiyang railway line started on Wednesday. (Xinhua/Liu Xu)

Aerial photo shows workers laying railway tracks at the construction site of the Chengdu-Guiyang railway line in Bijie, southwest China's Guizhou Province, Oct. 10, 2018. The track laying work of the Yunnan-Guizhou section of the Chengdu-Guiyang railway line started on Wednesday. (Xinhua/Liu Xu)

Aerial photo shows workers laying railway tracks at the construction site of the Chengdu-Guiyang railway line in Bijie, southwest China's Guizhou Province, Oct. 10, 2018. The track laying work of the Yunnan-Guizhou section of the Chengdu-Guiyang railway line started on Wednesday. (Xinhua/Liu Xu)