The line will be designed for 200km/h operation and will be used by freight trains as well as passenger services.
The project is due to be completed in 2020, reducing the journey time between the two cities to around four hours.
CONSTRUCTION is expected to begin in October on a 339km direct line linking Chongqing with Changsha, the capital of China's Hunan province, after China's Ministry of Environmental Protection approved plans for the Yuan 37.6bn ($US 6.1bn) project.
The line will be designed for 200km/h operation and will be used by freight trains as well as passenger services.
The project is due to be completed in 2020, reducing the journey time between the two cities to around four hours.