BANGKOK, Thailand – Thailand is moving forward with plans for two new urban rail projects, the Silver Line from Bang Na to Suvarnabhumi Airport and the Grey Line from Watcharapol to Thong Lor, with consultants now appointed to review the projects and prepare updated designs and environmental assessments. The Mass Rapid Transit Authority of Thailand (MRTA) has signed contracts for consultants to conduct feasibility studies, detailed design work, investment-model assessments, updated Environmental Impact Assessments (EIA), and studies on integrated fares for both projects.
MRTA Governor Kanphachon Udomthamphakdi said the studies are expected to take about 12 months, with the results targeted for submission to the Cabinet in 2028. The two projects were transferred to MRTA from the Bangkok Metropolitan Administration (BMA) and are initially expected to use a PPP Gross Cost model. Under the model, the government would invest in civil works and bear revenue risks, while private operators would be responsible for systems, construction-related work and long-term project management.
Silver Line to connect Bang Na with Suvarnabhumi
The Silver Line, linking Bang Na with Suvarnabhumi Airport, is being adjusted to provide a connection to the airport’s planned South Terminal. MRTA has already held preliminary discussions with Airports of Thailand (AOT) because part of the proposed alignment would require the use of AOT-controlled land. The project will be studied together with its investment structure, environmental impacts and integration with other rail services.
Grey Line planned to improve network connections
The Grey Line Phase 1, running from Watcharapol to Thong Lor, will also undergo a comprehensive review, including ways to improve connections with other mass-transit lines. The consultant contract for the Grey Line was signed on August 17, 2026, with MHPM Co. Ltd. as lead firm. The contract is worth 76.35 million baht and has a study period of 360 days. The Silver Line consultant contract was also signed on August 17, with Chotichinda Consultants Co. Ltd. as lead firm. The contract is valued at 75.70 million baht, also with a 360-day study period. The latest plan calls for the Silver Line study to be completed and submitted to the Cabinet around August 2028, with construction targeted to begin in July 2030 and services scheduled to open in October 2033.
Brown Line design still tied to expressway plans
Meanwhile, progress on the Brown Line, linking Khae Rai with Lam Sali in Bueng Kum over approximately 22.1 kilometers, remains dependent on the resolution of design issues involving proposed expressway projects. MRTA is reviewing the project, including integrated fares and modifications to the alignment around Bangkok’s eastern outer ring road. The changes need to be coordinated with the Expressway Authority of Thailand’s Northern Expressway Stage 3, including the N2 section between Prasert Manukitch Road and the eastern outer ring road, as well as the N1 expressway project connecting the Si Rat and Chalong Rat expressways. No final agreement has yet been reached on the revised design.
Joint fares targeted at 17–45 baht
MRTA is also working on the government’s integrated-ticket policy, which aims to introduce a 17–45 baht joint fare across participating urban rail services. Under the proposed system, passengers would pay the initial entry fee only once when traveling across different rail lines, rather than being charged a separate entry fee for each system. MRTA has already held discussions with Bangkok Expressway and Metro (BEM), which operates the Blue and Purple lines, while negotiations are also planned with the operators of the Yellow Line from Lat Phrao to Samrong and the Pink Line from Khae Rai to Min Buri. One issue being addressed is the installation of additional EMV card readers at Yellow and Pink Line stations.
At present, the two lines have only one or two EMV-enabled gates, generally located at swing gates used for special entry and exit. MRTA wants additional EMV readers installed, particularly at stations with heavy passenger traffic, to ensure the integrated fare system can operate smoothly. The Green and Gold lines, which fall under Bangkok Metropolitan Administration supervision, are subject to separate negotiations between the BMA and BTS. The government’s target is to introduce the 17–45 baht integrated fare on January 1, 2027.
More rail projects remain under review
Another proposed project, the Blue Line from Din Daeng to Sathorn, covering approximately 9.5 kilometers, remains in the preparation stage. MRTA considers the route to have potential for future development but plans to reassess its feasibility in 2029. With the Grey and Silver lines now entering the detailed study stage, authorities are seeking to move beyond planning and establish clearer investment, design and fare-integration frameworks before submitting the projects for Cabinet consideration.
