On March 11, 2022, Mass Rapid Transit Authority of Thailand signed a contract for the construction of the southern section of the purple tunnel of MRT Tao Poon - Rat Burana. In total, 6 contracts were signed with construction companies, including a Chinese-Thai engineering and construction company and an Italian-Thai development company.
The road will be built in 5 stages along the following segments: Tao Poon - National Library, National Library - Phan Fa, Phan Fa - Saphan Phut, Saphan Phut - Daukhanong, Daukhanong - Kru Nai. The total length of the route is 23.6 km, including an underground section with a length of 13.6 km or 10 stations and an aboveground section with a length of 10 km or 7 stations.
The construction is planned to be completed by 2027. The opening of new stations will significantly affect the price of real estate in the area of construction of the new MRT tunnel.