Construction initiates on Purple Line river tunnel project
Bangkok's MRT Purple Line Southern Extension: A Major Boost to Mass Transit Infrastructure
The MRT Purple Line Southern Extension, a 23.63 km-long mass transit project, is making significant progress in Bangkok. The extension, which features 17 new stations (10 underground and 7 elevated), is expected to be operational by 2028, a year later than initially planned.
The line will extend from Tao Poon station, connecting with the existing Purple Line northern section, and pass through important historic areas like Rattanakosin (Bangkok old town), enhancing connectivity with central Bangkok and interchanging with existing lines.
Construction contracts were signed in March 2022, and as of August 2025, tunneling under the Chao Phraya River, a critical segment of the extension, is in progress with 60% completion reported and expected to be completed by May 2026.
This extension will significantly improve access to central Bangkok and key tourist destinations, aiding the tourism sector and urban mobility.
Starting on Oct 1, passengers will pay no more than 20 baht per trip on any of the eight electric train lines in Bangkok and surrounding areas. However, it's important to note that this flat fare policy does not apply to any other modes of public transportation in the city.
The ministry overseeing this project has put heavy emphasis on safety during construction, with the Rail Transport Department and the Mass Rapid Transit Authority of Thailand (MRTA) directed to implement safety protocols, manage traffic, and implement flood prevention measures at construction sites.
Environmental impacts are being closely monitored, with efforts to control dust and maintain air quality during construction. The number of passengers is expected to increase to 250,000 per day from the current 150,000 due to the implementation of the 20-baht flat fare policy.
The MRT Purple Line's southern extension will integrate with the existing MRT Blue Line and Purple Line at the Tao Poon interchange. The completion of this project is scheduled for May next year, with full services across the entire MRT Purple Line's southern extension route scheduled for 2030.
This is the second such tunnel under the Chao Phraya River, a testament to the city's commitment to improving its mass transit infrastructure. The project is expected to significantly improve urban mobility, boost tourism, and enhance the quality of life for Bangkok's residents.
[1] Bangkok Post [2] The Nation [3] Thai PBS [4] Bangkok Metropolitan Administration [5] Mass Rapid Transit Authority of Thailand
The MRT Purple Line Southern Extension, a key project in Bangkok's mass transit infrastructure, is set to enhance the city's finance sector by boosting urban mobility and attracting more tourists. This integration with existing lines like the MRT Blue Line and Purple Line will also facilitate smooth transitions within the public-transit system, thereby improving transportation efficiency.
