The State Railway of Thailand (SRT) has signed contracts to construct the Red Line commuter rail extensions from Rangsit to Thammasat University and from Siriraj to Salaya, with a total value exceeding 20 billion baht. Construction is expected to start in July 2026 and complete by 2029, improving connectivity for residents of Bangkok and its metropolitan area.
On 19 May 2026 at Burachat Meeting Room, Krung Thep Aphiwat Central Station, Chatuchak District, Bangkok, the State Railway of Thailand (SRT) held a contract signing ceremony for the Red Line commuter rail extension (Dark Red Line) from Rangsit to Thammasat University Rangsit Campus with Unic Engineering and Construction Public Company Limited, valued at 6.057 billion baht, and for the Red Line extension (Light Red Line) from Siriraj to Taling Chan to Salaya with the UT Joint Venture (comprising 1. Unic Engineering and Construction Public Company Limited as Lead Firm, and 2. Trusty Construction Company Limited), valued at 14.72 billion baht. The contracts were signed by Mr. Anan Phonnimdaeng, Deputy Governor and Acting Governor of SRT, and Mr. Prasong Suwivatthanachai, Managing Director of Unic Engineering and Construction.
At the same event, an Integrity Pact was signed with the Anti-Corruption Organization of Thailand for the Dark Red Line extension from Rangsit to Thammasat University Rangsit Campus to promote transparency in project implementation, witnessed by Mr. Anan Jengnamkul, Deputy Governor of SRT.
Mr. Anan Phonnimdaeng, Deputy Governor and Acting Governor of the State Railway of Thailand, said, The Red Line commuter rail extension project from Rangsit to Thammasat University Rangsit Campus and from Siriraj to Taling Chan to Salaya is part of the government's rail transport development policy under the 20-year National Strategy (2018–2037) and the second phase of the Mass Rapid Transit Master Plan for Bangkok and its vicinity (M-MAP2). It aims to upgrade the rail network, alleviate traffic congestion, and sustainably accommodate future public travel needs. The project has been promoted and approved by the Cabinet since 2025. On 29 January 2026, the State Railway of Thailand Board resolved to contractUnicEngineering and Construction Public Company Limited to build the Dark Red Line extension from Rangsit to Thammasat University Rangsit Campus, and to contract the UT Joint Venture to build the Light Red Line extension from Siriraj to Taling Chan to Salaya, including three additional stations (Rama VI Bridge Station, Bang Kruai-EGAT Station, and Ban Chimphli Station).
divided into two main lines:
Dark Red Line (Rangsit to Thammasat University Rangsit Campus) covers 8.84 kilometers at ground level, consisting of four stations: Khlong Nueng, Bangkok University, Chiang Rak, and Thammasat University Rangsit Campus. The project mainly uses existing railway land, requiring additional land expropriation of only 14 rai.
Light Red Line (Siriraj to Taling Chan to Salaya and three additional stations) spans a total of 20.50 kilometers, with both ground level and elevated tracks, comprising nine stations from Siriraj to Salaya. This project uses entirely SRT land with no additional land expropriation required.
Next, SRT will sign contracts for construction supervision: for the Siriraj–Taling Chan–Salaya section around 15 June 2026 and for the Rangsit–Thammasat University Rangsit Campus section around 9 July 2026. Construction Notices to Proceed will be issued to both contractors simultaneously in July 2026. The construction period is 36 months (3 years), with completion scheduled for 2029. Once operational, the Red Line extensions from Rangsit to Thammasat University Rangsit Campus and from Siriraj to Taling Chan to Salaya will reduce travel time from Pathum Thani Province to Bangkok and improve access to the Thonburi-Salaya area via the main urban rail network. The projects will also alleviate traffic congestion, promote economic development around stations, and contribute to environmental sustainability by reducing national energy consumption, Mr. Anan said.
Read the article " State Policy " for more information.