Bangkok Expressway and Metro Public Company Limited, or BEM, has clarified the cause of an electrical short circuit along the track of the Metropolitan Rapid Transit Chaloem Ratchamongkhon Line, also known as the Blue Line, between Tao Poon station and Bang Pho station on Sunday, September 20, 2026. The company immediately suspended service on the Blue Line and the Purple Line in line with its incident management standards, while ensuring passengers were evacuated from the stations safely. A joint investigation with the Mass Rapid Transit Authority of Thailand, or MRTA, found the cause was a spark from a 750-volt direct current cable set, which damaged the power supply system and the signalling system. The Purple Line was unaffected and continued normal service. BEM mobilised teams of engineers and specialists to inspect, rectify and repair the affected systems continuously over 12 hours, covering the signalling system, the SCADA system, the communications system, the cabling system and the third rail power supply system. After repairs were completed, the systems were tested in detail, including the deployment of two inspection trains to run test journeys along the entire route on both sides of the incident site. The inspection results found that the train operation system, the power supply system and related systems were functioning fully and normally, with no further damage affecting safety. BEM therefore confirmed it was ready to resume normal Blue Line service on September 21, 2026, at all stations, and will tighten inspection and maintenance, especially during the rainy season, to prevent a recurrence.
Bangkok Expressway and Metro Public Company LimitedAn electrical short circuit damaged the Blue Line's power and signalling systems, forcing a service suspension and 12-hour repairs.
