Large crowds of commuters were stranded at BTS stations by a malfunction in the signal system during the morning rush hours on Monday. Regular services did not begin resuming until around 10am.
Bangkok Mass Transit System Plc (BTSC) reported difficulties with its signal system about 6.15am and kept sending messages through Twitter that its trains would be 10-15 minutes late at each station.
The malfunction happened on the downtown and main Sukhumvit and Silom lines.
Queues of commuters stretched from elevated stations down stairways and onto footpaths as staff prevented more people entering the already overcrowded platform areas.
Some passengers complained that they lost about 30 minutes to stalled trains at several stations.
About 10am the company said the problem was solved and it was trying to clear congestion at stations.
BTS executive director Anat Arbhabhirama said the problem occurred at Siam station, where a new signal system was disrupted by interference. Drivers had to operate trains manually there, causing delays to the whole network.
Transport Minister Arkhom Termpittayapaisith said problems happened too often with BTS services and the operator should use buses to help commuters if its trains were delayed 10-15 minutes. He would discuss the matter with the operator soon.
Video by Om Jotikasthira