The line is 136.3 km ( 85 mi ) in length .
The line was built during the Cultural Revolution from 1966 to 1975 to exploit coal fields in western Guizhou and support inland industries as part of the Third Front .
The line is 136.3 km ( 85 mi ) in length and was built during the Cultural Revolution from 1966 to 1975 to exploit coal fields in western Guizhou and support inland industries as part of the Third Front .