The Mass Rapid Transit Authority of Thailand (MRTA) updated the progress of the Southern Purple Line MRT from Tao Poon to Rat Burana, reporting overall civil work completion at 75.90% and preparing for a 2030 service opening. They explained the recent tunnel water seepage incident was caused by natural factors.
Information from the Mass Rapid Transit Authority of Thailand (MRTA) states that the Southern Purple Line MRT project from Tao Poon to Rat Burana (Kanchanaphisek Ring) — known as the "Southern Purple Line" — is a key rail project connecting the northern network to the southern side of the Chao Phraya River. Progress continues steadily, with civil work averaging 75.90% complete as of the end of June 2026, and service is expected to open as planned in 2030.
During construction, the project faced unexpected incidents caused by both engineering challenges and natural disasters, with two major events:
Road subsidence incident. Occurred on 24 September 2025 near the entrance of Vajira Hospital on Samsen Road, close to the construction site of Entrance-Exit 4 at Vajira Hospital Station (PP19).
Tunnel water leakage incident. Occurred most recently on 8 July 2026, primarily due to heavy natural rainfall causing water to seep into the sump pit about 30 meters deep under the underground MRT tunnel at Wongwian Yai intersection, located in Contract 4 area (Phuttha Bridge–Dao Khanong section). This led to a large volume of water entering the construction tunnel.
The Southern Purple Line MRT project is divided into six main contracts, with progress in each as follows:
Contract 1 (Tao Poon–National Library) is 89.10% complete, the most advanced section, with major station structures and underground tunnels largely in place.
Contract 2 (National Library–Phan Fa) is 86.05% complete, progressing with underground structure and station construction, serving as a key connection in the city center.
Contract 3 (Phan Fa–Phuttha Bridge) is 69.45% complete, located in the inner city requiring careful construction management to minimize traffic impact.
Contract 4 (Phuttha Bridge–Dao Khanong) is 74.69% complete, with accelerating tunnel and station construction to support cross-Chao Phraya travel to Thonburi side.
Contract 5 (Dao Khanong–Kru Nai) is 54.11% complete, with main structures for the park-and-ride and train parking buildings under construction.
Contract 6 (Rail system installation along the route) is 66.25% complete, involving track laying, supporting structures, and train operation components.
The Southern Purple Line MRT project from Tao Poon to Rat Burana is among the country's major transport infrastructure initiatives, crucial for connecting Bangkok's rail networks and metropolitan areas. Upon completion, it will expand travel options, alleviate traffic on main roads, and enhance the city's public transport efficiency.
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