Royal State Railways

SRT was founded as the Royal State Railways of Siam (RSR) in 1890. Construction of the Bangkok-Ayutthaya railway (71 km), the first part of the Northern Line, was started in 1891 and completed on May 23, 1892.

The Thonburi-Phetchaburi line (150 km), later the Southern Line, was opened on June 19, 1903. The Northern Line was originally built as standard gauge, but in September 1919 it was decided to standardize on meter gauge and the Northern Line was regauged during the next ten years. On July 1, 1951, RSR changed its name to the present State Railway of Thailand. In 2005 SRT had 4,070 km of track, all of it meter gauge. Nearly all is single-track, although some important sections around Bangkok are double or triple-tracked and there are plans to extend this