SRT Light Red Line
The SRT Light Red Line is part of the planned SRT Red Lines suburban railway system to serve the Bangkok Metropolitan Region. It will run east–west from Sala Ya in Phutthamonthon District of Nakhon Pathom Province to Hua Mak Railway Station in Bangkok. The segment from Taling Chan to Bang Son opened for limited, free trial service on December 5, 2012. The trial service operated for only 13 months with a limited 12 services a day operated on the line until all services were fully suspended on 13 January 2014 due to a lack of rolling stock and pending further notice.
The reopening of the Light Red line is contingent upon the completion of the new Bang Sue and delivery of rolling stock. The line is expected to reopen in January 2021.
In July 2016, the cabinet approved the construction of the Bang Sue–Phaya Thai–Makkasan–Hua Mak segment. However, the 12 km, 4 station western extension Taling Chan to Salaya was due to be tendered first by September 2018 and then slated for the 2nd half of 2019. However, the tender has further been delayed until 2021 as the Transport Minister has requested the new Department of Railways to investigate conducting PPP tenders for this extension.
Route Alignment
The first 15 km section runs from Bang Sue to Taling Chan in Thonburi. The line will then be extended 12 km west to Sala Ya in Phutthamonthon District of Nakhon Pathom Province. Finally, the line will be extended south from section to Bang Sue via Phaya Thai and then east to Hua Mak Railway Station in Bangkok.History
Bang Sue–Taling Chan
The contract for the initial stages from Taling Chan to Bang Sue was signed on December 15, 2008, with the contract awarded to the Unique-Chun Wo consortium. Construction started in early 2010 but was delayed for a few months due to the late 2011 floods in Bangkok which inundated the route. Construction was completed by the 3rd quarter of 2012. Testing began in September 2012 for a 3-month period. Bang Sue–Taling Chan Rail Electrification included in Contract 3 of SRT Dark Red Line Bang Sue - Rangsit which is under construction. Electrification will be completed by 2020. By the end of September 2019, Electrical and Signalling installation was at 45.60%.Additional stations
Two additional stations on either side of the Chao Praya river have been approved to be built, at Rama 6 bridge and Bang Kruay. However, as of July 2020 no contracts have been tendered to build these two stations given the delays with the Salaya section tender.Operation and suspension
The line opened for free limited trial service on 5 Dec 2012 between Taling Chan Station and Bang Son Station. The line is operated with 2 refurbished DMUs running a very limited service. There are 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 ride the service. As of 14 September 2013, weekend services were cancelled. Effective on 13 January 2014 all services were suspended until further notice. Until the Bang Sue Central Station is completed in early 2021 and the SRT has new rolling stock this line will not operate.Rolling stock
The 3rd contract for the Dark Red Line is for electrical and systems and procuring EMU rolling stock for both the SRT Light Red and SRT Dark Red lines. An overhead cantenary electrical system will be installed. As of April 2014, only 2 bidders remained but one of the bidding consortium's was disqualified on due to the fact that one of the consortium members had convictions for bribery in an Indonesian bidding process.This left MHSC Consortium as the sole bidder qualified for the contract. However, their bid of 28,899 billions Baht was above the SRT median price of 26 billions baht which was set in 2010. The MHSC Consortium argued that their bid reflects 2013 prices after the minimum wage increase of January 2012. Finally, after a 2-year delay in the bidding process, in July 2014 JICA approved the loan for Contract 3. However, the coup of May 2014 delayed finalization leading to further review and negotiations. By mid 2016, negotiations had concluded and Hitachi promised that all rolling stock for the Dark Red line would be delivered by 2020. The contract specifies 25 EMUs consisting of ten 4 car sets and fifteen 6 car sets for 130 cars in total.
In late September 2019 the first 2 sets of rolling stock were shipped from Japan and both arrived in Thailand at Laem Chabang port on 12 October 2019 for shipment to Bangkok. By March 2020, 5 sets had been delivered.
As of July 2020, 13 sets - 7 of the 6 car sets and 6 of the 4 car sets - of the ordered 25 sets of rolling stock had been delivered with a further 2 sets due to be delivered by August 2020.
Future extensions
Construction segments based on M-Map:| Phase | Segment | Length | Progress |
| I | Bang Sue-Taling Chan | Constructed. Pending electrification | |
| II | Taling Chan-Salaya | Cabinet Approved | |
| III | Taling Chan-Siraj | Cabinet Approved | |
| IV | Bang Sue-Hua Mark | Planned | |
| V | Salaya-Nakhon Pathom | Suggested long term |
Phase II Taling Chan-Salaya Extension
The SRT Light Red Line is planned to be extended by 12 km west to Salaya. 4 stations are planned be built along the existing SRT corridor;1) Ban Chimplee station,
2) Kanchanaphisek,
3) Sala Thammasob,
4) Salaya.
The western extension from Taling Chan to Salaya was originally planned to be tendered by September 2018 after receiving Thai Cabinet approval in July 2016. This was then delayed to the 2nd half of 2019. However, the tender has further been delayed until 2021 as the Transport Minister has requested the new Department of Railways to investigate conducting PPP tenders for this extension.
Phase III Taling Chan-Siriraj spur line
The SRT operates existing intercity services from Thonburi station to Kanchananburi. This line is planned to be converted to a spur line of the existing Light Red line, from Taling Chan to Thonburi/ Siriraj.In August 2012, the SRT proposed that 3 stations be built for this 6.5 km route:
1) Talingchan Floating Market station at Bang Ramad,
2) Charansanitwongse station
3) Thonburi/Siraraj station
It is worth noting that originally the MRT Orange Line was planned to be built along this alignment to Taling Chan. This spur line will be constructed once the extension to Salaya has started construction.
Phase IV Bang Sue–Hua Mak
There will be stations at Ratchawithi, Phaya Thai, Makkasan and Hua Mak.This section can only be progressed once Bang Sue Central Station is completed and will have a narrow right of way given the current ARL viaduct and ARL stations.