Northeastern Line (Thailand)

The Northeastern Line is a railway line in Thailand that connects the capital Bangkok with the northeast region of Isan. The section from Bangkok to Nakhon Ratchasima is Thailand's first line that opened for passenger service. The line is also a key section on the central route of the Kunming–Singapore railway.

Route description
The Northeastern Line shares tracks with Northern Line between Bangkok and Ban Phachi Junction. It has three main branches:
 * Ubon Ratchathani Main Line, between Bangkok and Ubon Ratchathani
 * Nong Khai Main Line, between Bangkok and Nong Khai, branching off after Nakhon Ratchasima. The line also crosses the Thai-Lao border into Thanaleng, with an extension to Khamsavath railway station being opened in 2023.
 * Lam Narai Branch Line

Ubon Ratchathani Main Line

 * 9 March 1891 - started construction
 * 26 March 1896 - opened Bangkok – Ayutthaya
 * 1 November 1897 - Ayutthaya – Kaeng Khoi
 * 21 December 1900 - opened Kaeng Khoi – Nakhon Ratchasima
 * 1 November 1922 - opened Nakhon Ratchasima–Tha Chang near a pier on Mun river that allowed boat service between Tha Chang and Ubon Ratchathani along Mun river
 * 1 April 1925 - opened Tha Chang – Buriram
 * 1 August 1928 - opened Buriram – Sisaket
 * 1 April 1930 - opened Sisaket – Ubon Ratchathani

SRT also built a short railway line from Bung Wai to Ban Pho Mun which was opened on 1 August 1930, but the line was closed on 1 December 1954 due to the construction of Seri Prachathippatai bridge (officially opened in 1955) that allowed the connection between Ubon Ratchathani city and Ubon Ratchathani without the need for ferry across Mun river.

Nong Khai Main Line

 * 1 April 1933 - opened Nakhon Ratchasima – Khon Kaen
 * 24 June 1941 - Khon Kaen – Udon Thani
 * 13 September 1955 - Udon Thani – Na Tha (first Nong Khai station)
 * 31 July 1958 - Na Tha – Nong Khai (Talat Nong Khai, second Nong Khai station)
 * 2008 - Nong Khai (new, third and current Nong Khai station) – Talat Nong Khai section closed.
 * 5 March 2009 - Nong Khai – Thanaleng (Vientiane Prefecture)
 * 31 October 2023 - Thanaleng – Khamsavath (Vientiane Prefecture)

Kaeng Khoi–Bua Yai (Lam Narai) Branch Line

 * 19 August 1967 - entire Kaeng Khoi Junction–Bua Yai Junction line opened.