The Purple Line southern extension project will offer a direct route from Nonthaburi, a district located just north of Bangkok, to the south-eastern part of the capital. The line will further expand the city’s metro rail system and provide a more convenient and sustainable way of travelling.
The existing Purple Line begins from Khlong Bang Phai in Nonthaburi and ends in Tao Poon in central Bangkok. The proposed alignment will have 17 additional stations, crossing beneath Bangkok’s old town and ending in Rat Burana in the south. It will connect to existing metro lines, making transfers easier and providing transportation alternatives across the Bangkok and its surrounding districts.
The extension’s total planned length is 23.6 kilometers, of which 12.7 kilometers will underground and 10 kilometers will be elevated. Along this alignment, 10 stations will be built underground and seven will be elevated.
AECOM was commissioned by the client, Ch Karnchang – Sino-Thai Engineering & Construction Joint Venture (CKST-PL JV), to provide detailed design and construction stage technical services for Contract 1 and Contract 2, covering architectural, engineering, alignment and tunneling.
Contract 1 involves the design and construction of approximately 4.85 kilometers of underground structures from the Tao Pun section to the National Library section. This includes three underground stations, bored tunnels, cut-and-cover tunnels, a viaduct, an intervention shaft and ventilation shaft. This also includes the construction of the connections to the existing Purple Line North station, which is in operational service.
Contract 2 refers to the section from the National Library to Phan Fa. It involves the design and construction of approximately 2.35 kilometers of underground structures, including three underground stations, bored tunnels and one intervention shaft.
AECOM is working on this project through a consortium with local partners TEAM Consulting Engineering and Management Public Co., Ltd. and Geotechnical & Foundation Engineering Co., Ltd. Main delivery support to the local Thailand team is from the Malaysia office, plus support from the Southeast Asia transportation leadership team. The team in Thailand will manage the project, communicate with the clients and other project stakeholders, resolve technical issues on the ground and to see through the construction stage.
The project is targeted to be completed in 2027 and is expected to attract more commuters to use the metro rail. Once completed, it will help reduce private cars on the road, alleviate traffic congestion and lower carbon emissions from vehicles.