The State Railway of Thailand (SRT) has apologised to passengers on the Sungai Kolok-Bangkok special express for the rundown condition of a carriage.

The Facebook post by a train passenger highlighted the poor condition of the third-class car he was travelling in, including a broken window pane and tattered, broken seat.

The state railway's public relations chief said SRT's governor was made aware of the report and had ordered an investigation.

The maintenance, passenger services and train operations departments would examine and make sure all locomotives and passenger cars were in good condition before being put into service.

The passenger car in question would be restored to a good condition, the chief said.

He said the SRT had received a good response from commuters and tourists for its convenience and low fares, and was open to recommendations to make improvements.