On 12th August 2024, the Thai state railway SRT put the double-track extension of the 421 km long Nakhon Pathom – Chumphon section of the southern line into operation. The new line runs parallel to the original line through the provinces of Ratchaburi, Phetchaburi, and Prachuap Khiri Khan. In addition to the double-track expansion of the Nakhon Pathom – Chumphon line, the SRT is planning to double the tracks on seven other lines and to build two further lines between Den Chai and Chiang Khong, as well as between Ban Phai and Nakhon Phanom. The expansion is part of a nationwide plan to increase the proportion of double-track lines to 65% by 2029.
