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. (Photos: Xinhua)

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.

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.

A worker lays 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.

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.

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.

An 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.

An 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.

An 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.

A worker lays 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.