The SRT Light Red Line, or Nakhon Withi Line () is a between Krung Thep Aphiwat Central Terminal and Taling Chan and is part of the SRT Red Lines suburban railway system serving the greater Bangkok Metropolitan Region.
An initial segment from Taling Chan to Bang Son previously opened for limited, free trial service between 5 December 2012 and 13 January 2014 with only 12 services a day until all services were fully suspended due to the lack of rolling stock. After a much-delayed completion of the electrification of the line and the construction of Krung Thep Aphiwat Central Terminal, the line finally opened for trial operations on 2 August 2021. Full commercial services commenced on 29 November 2021.
A much delayed western extension of the line from Taling Chan to Salaya was due to be tendered in June 2022. However, this was later delayed to December 2022 and then until February 2023. With the 14 May 2023 national elections and the ongoing delays in the formation of a new government, it is unlikely that the tenders will be issued until late 2023. In late June, a MOT source expressed that the extension is likely be taken to Cabinet for approval in October 2023 and if approved, a tender could be issued in the first quarter of 2024.
When fully completed, the line will run east–west from Sala Ya in Phutthamonthon District of Nakhon Pathom Province to Hua Mak railway station in Bangkok.
Route alignment
The section runs from Krung Thep Aphiwat Central Terminal (the new Intercity Terminal in Chatuchak District) to Bang Son where it interchanges with the MRT Purple Line. It then continues west and crosses the Chao Phraya River to the Thonburi side of Bangkok before continuing farther west to Taling Chan where it terminates. Krung Thep Aphiwat Central Terminal Intercity Terminal provides interchange with the SRT Dark Red Line and MRT Blue Line. The line will be extended west to Sala Ya in Phutthamonthon District of Nakhon Pathom Province. Finally, the line will be extended south from Krung Thep Aphiwat Central Terminal via Phaya Thai and then east to Hua Mak Railway Station in the east of Bangkok where it will interchange with the MRT Yellow Line.
History
In 2004, in conjunction with OTP, the SRT began formulating plans for a new, modern suburban network in Bangkok along existing SRT alignments to replace the existing, limited services. On 7 November 2006, the Thai Cabinet passed a resolution to approve the framework of the new network with the SRT Light Red line being DMU operations while the SRT Dark Red Light would be EMU. The Cabinet approved the line on 22 May 2007 with a budget of 13.133 billion baht. At the time, it was expected that the full iine could be completed within 15-20 years. Contracts for construction of the initial section from Taling Chan to Bang Sue were awarded by the SRT on 29 September 2009. The contract was signed on 15 December 2008, with the contract awarded to the Unique-Chun Wo consortium.
Construction
Construction started in early 2010 after some site access delays related to slum dwellers who had been residing various sections of SRT land for many years. Works progressed well but were thereafter delayed for a few months due to the late 2011 floods in Bangkok wth floodwaters inundated on parts of the route. Construction was completed by the 3rd quarter of 2012. Testing began in September 2012 for a 3-month period.
2012-4 trial operation and suspension
The line opened for free limited trial service on 5 December 2012 between Taling Chan Station and Bang Son Station. The line was operated with 2 refurbished DMUs running a very limited service. There were only 6 services each way a day every 60 minutes from 6am to 8am and from 4pm to 7pm. As such, only a few hundred passengers a day rode the service. On 14 September 2013, weekend services were cancelled. Effective 13 January 2014, all services were suspended until electrification works could be completed and rolling stock procured which was expected to be by the end of 2018.
Electrification and 2021 opening
The reopening of the SRT Light Red line was contingent upon the completion of the new Krung Thep Aphiwat Central Terminal, delivery of rolling stock and installation of the overhead catenary electrical system between Bang Sue–Taling Chan which was funded as part of the SRT Dark Red Line contract 3 as the SRT had subsequently decided to change the line from DMU to EMU operations. Full electrification was planned to be completed by 2020 when the SRT Dark Red line was completed. By the end of September 2019, Electrical and Signaling installation was at 45.60%.