View source for SRT Light Red Line

{{Short description|Mass rapid rail in Bangkok, Thailand}}
{{Use dmy dates|date=February 2022}}
{{Infobox rail line
| box_width                       = 300px
| name                            = SRT Light Red Line
| other_name                      = Nakhon Withi Line
| native_name                     = สายนครวิถี
| native_name_lang                = th
| color                           = {{rcr|SRT Red Lines|Light Red}}
| logo                            = SRT Bangkok Commuter Rail Light Red Line Logo.svg
| logo_width                      = 80px
| logo_alt                        = 
| image                           = SRTRedline 2000series WiteePhotography. For wikipedia.jpg
| image_width                     = 300px
| image_alt                       = 
| caption                         = SRT Light Red Line train at [[Bang Bamru railway station]]
| type                            = [[Commuter rail]]
| system                          = [[SRT Red Lines]]
| status                          = Operational (Phase I)
| locale                          = [[Bangkok Metropolitan Region]]
| start                           = [[Krung Thep Aphiwat Central Terminal|Krung Thep Aphiwat]]
| end                             = {{stnlnk|Taling Chan}}
| stations                        = 4
| routes                          = 
| daily_ridership                 = 
| ridership2                      = 
| planopen                        = <!--{{Start date|YYYY|MM|DD|df=y}}-->
| open                            = {{Start date|2021|8|2|df=y}} (free trial service)<ref name=bkkpost030821>{{cite news|date=3 August 2021|title=Free rides along Red Line until November|newspaper=Bangkok Post|url=https://www.bangkokpost.com/thailand/general/2158775/free-rides-along-red-line-until-november}}</ref><br />{{Start date|2021|11|29|df=y}} (commercial service)<ref>{{cite news|title=Red Line to charge fares from Nov 29|url=https://www.bangkokpost.com/thailand/general/2217763/red-line-to-charge-fares-from-nov-29|newspaper=Bangkok Post|date=18 November 2021}}</ref>
| yearcommenced                   = <!--{{Start date|YYYY|MM|DD|df=y}}-->
| yearcompleted                   = <!--{{Start date|YYYY|MM|DD|df=y}}-->
| close                           = <!--{{Start date|YYYY|MM|DD|df=y}}-->
| event1label                     = 
| event1                          = 
| event2label                     = 
| event2                          = 
| event3label                     = 
| event3                          = 
| owner                           = [[State Railway of Thailand]]
| operator                        = SRTET - SRT Electrified Train Company Limited
| character                       = Elevated
| depot                           = Chatuchak, [[Bangkok]]
| stock                           = [[Hitachi A-train|Hitachi AT100]]
| linelength_km                   = 15.26
| linelength_mi                   = 
| linelength                      = 
| tracklength_km                  = 
| tracklength_mi                  = 
| tracklength                     = 
| tracks                          = 2
| gauge                           = {{track gauge|metre|allk=on}}
| old_gauge                       = 
| load_gauge                      = 
| minradius                       = 
| racksystem                      = 
| routenumber                     = 
| linenumber                      = 
| electrification                 = {{25 kV 50 Hz}} [[overhead line|overhead catenary]]
| speed_km/h                      = 90
| speed_mph                       = 
| speed                           = 
| signalling                      = [[Thales Rail Signalling Solutions|Thales]] AlTrac for [[European Rail Traffic Management System|ERTMS]] ([[European Train Control System#Level 1|ECTS Level 1]])<ref>{{Cite press release|title=Bangkok's suburban train will boost its capacity by up to 40% with Thales|date=2018-05-24|publisher=[[Thales Rail Signalling Solutions|Thales]]|url=https://www.thalesgroup.com/en/worldwide/transportation/press-release/bangkoks-suburban-train-will-boost-its-capacity-40-thales}}</ref>
| elevation_m                     = 
| elevation_ft                    = 
| elevation                       = 
| website                         = [http://www.railway.co.th/resultproject/project_redline.asp State Railway of Thailand]
| map                             = {{SRT Light Red Line route}}
| map_name                        = 
| map_state                       = collapsed
| embedded                        = 
}}

The '''SRT Light Red Line''', or '''Nakhon Withi Line''' ({{langx|th|รถไฟชานเมือง สายนครวิถี}}) is a {{Cvt|15|km}} 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]]. The construction plan is split into 5 phases. 

Phase I running between [[Krung Thep Aphiwat Central Terminal]] and Taling Chan opened for trial operations on 2 August 2021 with full commercial services commencing on 29 November 2021.<ref>{{cite news |title=Red Line to charge fares from Nov 29 |url=https://www.bangkokpost.com/thailand/general/2217763/red-line-to-charge-fares-from-nov-29 |newspaper=Bangkok Post |date=18 November 2021 }}</ref> An initial segment from [[Taling Chan]] to [[Bang Son railway station|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.

Extensions for Phase II running from Taling Chan to Salaya and Phase III spur line from Taling Chan to Siriraj were approved by the Thai Cabinet on 17 June 2025. In addition, three infill stations of Rama VI Bridge, Bang Kruai (EGAT) and Ban Chim Phli were approved under a single construction contract totalling 20.5km. The proposal had been submitted to the Cabinet secretariat on 27 March 2025 and expects to open bidding in late-2025. The approved budget decreased from 16.847 to 15.176 billion baht, with construction projected to run from January 2026 to December 2028 and services beginning in 2029.<ref>{{cite web |url=https://www.bangkokbiznews.com/business/economic/1185249?|title=ครม.ไฟเขียวสร้างส่วนต่อขยาย 'รถไฟสายสีแดง' ประมูลทันทีปีนี้ |trans-title=Cabinet approves Red Line extension, to tender this year |work=BangkokBizNews |date=17 June 2025 |language=th |access-date=19 June 2025}}</ref>

As of June 2025, there are no updates for Phase IV and Phase V of the project. When fully completed, the line will run east–west from [[Salaya, Thailand]] in [[Phutthamonthon District]] of [[Nakhon Pathom Province]] to [[Hua Mak railway station]] in [[Bangkok]].

==Route alignment==
The {{Cvt|15|km}} section runs from [[Krung Thep Aphiwat Central Terminal]] (the new Intercity Terminal in [[Chatuchak District]]) to [[Bang Son railway station|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 {{Cvt|14.8|km}} 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 Station|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.<ref>{{cite web|url=https://procurement.railway.co.th/resultproject/project_redline.asp?redline=1|title=SRT Red Line project website}}</ref> 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 [[Krung Thep Aphiwat Central Terminal|Bang Sue]] were awarded by the SRT on 29 September 2009.<ref>SRT awards rail contract, Bangkok Post, 30 September 2008</ref> The contract was signed on 15 December 2008, with the contract awarded to the Unique-Chun Wo consortium.<ref>{{cite news |first=Amornrat |last=Mahitthirook |title=Red Line bidding to open in August |url=http://www.bangkokpost.com/news/local/15270/ |newspaper=Bangkok Post |date=19 April 2009 }}</ref>

=== Construction ===
[[File:Bang Son Commuter station, Aug 2016 (1).jpg|thumb|250px|[[Bang Son railway station|Bang Son Commuter station]] on SRT Light Red Line]]
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 with 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.<ref>{{cite news |title=Testing underway on Bangkok suburban line|url=https://www.railwaygazette.com/testing-underway-on-bangkok-suburban-line/37273.article |newspaper=International Railway Gazette |date=7 September 2012}}</ref>

=== 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 railway station|Bang Son Station]]. The line was operated with 2 refurbished [[Diesel multiple unit|DMU]]s 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.<ref>http://www.thairath.co.th/content/region/312438, 6 March 2013</ref> On 14 September 2013, weekend services were cancelled.<ref>https://www.facebook.com/photo.php?fbid=3527350840078&set=a.1465205967745.44001.1761413660&type=1&ref=nf {{User-generated source|certain=yes|date=March 2022}}</ref> 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 ===
[[File:Bang Son Railway Station 20230218-5.jpg|thumb|250px|Ticket hall at Bang Son railway station.]]
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%.<ref name="prachachat.net">{{cite news|date=27 September 2019|title=ธรรมศาสตร์พบ "ศักดิ์สยาม" เร่งสร้างรถไฟฟ้าสายสีแดงส่วนต่อขยายรังสิต "รถไฟ" คาดลงเข็มมิ.ย.63|newspaper=Prachachat|url=https://www.prachachat.net/property/news-375700}}</ref>

By June 2020, installation of the catenary system was at 76.82%.<ref>{{cite news|date=20 July 2020|title=กางไทม์ไลน์สายสีแดง เปิดทดลองฟรี มิ.ย. 64 - "ศักดิ์สยาม" เรียกถกเคาะ PPP|newspaper=Manager Online|url=https://mgronline.com/business/detail/9630000074088}}</ref> The line was expected to reopen in January 2021<ref name="prachachat.net"/> after test runs began in late October 2020.<ref>{{cite news|date=19 September 2020|title=ไม่รอเอกชนร่วมทุนฯ! รฟท.เปิดทดสอบเดินรถไฟฟ้า 'สายสีแดง' กลางปี 64-ลุยทางคู่สายอีสาน|newspaper=Isranews|url=https://www.isranews.org/article/isranews-news/92096-railway-policy-red-line.html}}</ref> In mid-November 2020, the Minister of Transport announced that free trial operations would operate from March to May 2021 with full-service operations expected in November 2021.<ref>{{cite news|date=16 November 2020|title=รถไฟสายสีแดง มี.ค.64|newspaper=Thai PBS|url=https://news.thaipbs.or.th/content/298393}}</ref> In late February 2021, the SRT confirmed that free trial operations would commence on 26 March 2021 with full commercial operations starting on 28 July 2021.<ref>{{cite news|date=24 February 2021|title=Red Line test run next month|newspaper=Bangkok Post|url=https://www.bangkokpost.com/thailand/general/2073283/red-line-test-run-next-month}}</ref> In July, the SRT postponed the service and the free trial operations commenced on 2 August 2021 with full commercial operations due to start on 28 November 2021.<ref>{{Cite news|url=https://www.prachachat.net/property/news-728234|title = ประยุทธ์ เปิดปฐมฤกษ์รถไฟฟ้าสายสีแดง 2 สิงหาคมนี้| newspaper=ประชาชาติธุรกิจ |date = 31 July 2021| author1=Prachachat }}</ref><ref name=bkkpost030821/>

==Rolling stock==
[[File:SRT Light Red Line at Bang Son Railway Station.jpg|thumb|250px|A Hitachi-built SRT 1000 series at Bang Son railway station.]]
The 3rd contract for the [[SRT Dark Red Line]] was for the electrical and mechanical (E&M) systems and procuring EMU rolling stock for both the SRT Light Red and SRT Dark Red lines with an overhead catenary electrical system at {{25 kV 50 Hz}}. In April 2014, only 2 bidders remained but one of the bidding consortiums was disqualified on due to the fact that one of the consortium members ([[Marubeni Corporation]]) had convictions for bribery in an Indonesian bidding process.<ref>{{Cite news|url=http://www.prachachat.net/news_detail.php?newsid=1388935951|title = ข่าวรอบวัน| newspaper=ประชาชาติธุรกิจ |archive-url=https://web.archive.org/web/20140728120530/http://www.prachachat.net/news_detail.php?newsid=1388935951 |archive-date=28 July 2014}}</ref>

This left the MHSC Consortium (consisting of [[Mitsubishi Heavy Industries]], [[Hitachi]], and [[Sumitomo Corporation]]) as the sole bidder qualified for the contract. However, their bid of 28,899 billion Baht was above the SRT median price of 26 billion baht which was set in 2010. The MHSC Consortium argued that their bid reflected 2013 prices after the national minimum wage increase from 1 January 2012. Finally in July 2014, after a 2-year delay in the bidding process [[Japan International Cooperation Agency|JICA]] approved the loan for Contract 3.<ref>'JICA green light red line contract 3 Bang Sue - Rangsit after 2 years delay'. 24 July 2014. Economic News, http://pantip.com/topic/32365743</ref> 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.<ref>{{cite news |title=Hitachi vows on-time train carriage delivery for Red Line|url=http://www.nationmultimedia.com/business/Hitachi-vows-on-time-train-carriage-delivery-for-R-30293885.html |archive-url=https://web.archive.org/web/20160828000938/http://www.nationmultimedia.com/business/Hitachi-vows-on-time-train-carriage-delivery-for-R-30293885.html |url-status=dead |archive-date=28 August 2016 |newspaper=The Nation |date=27 August 2016 }}</ref> The contract specified 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<ref>{{cite news |title=Hitachi ships first Bangkok Red Line trains|url=https://www.railjournal.com/regions/asia/hitachi-ships-first-bangkok-red-line-trains |newspaper=International Railway Journal |date=27 September 2019}}</ref> and both arrived in Thailand at Laem Chabang port on 12 October 2019 for shipment to Bangkok.<ref>{{cite news |title=ถึงไทยแล้ว! รถไฟสายสีแดง 2 ขบวนแรก |url=https://mgronline.com/business/detail/9620000098623 |newspaper=Manager Online |date=13 October 2019}}</ref> By March 2020, 5 sets had been delivered.<ref>{{cite news |title=Red Line train trials to begin in October |url=https://www.bangkokpost.com/thailand/general/1881625/red-line-train-trials-to-begin-in-october |newspaper=Bangkok Post |date=19 March 2020 }}</ref> 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.<ref>{{cite news |title=รฟท.สร้างเสร็จ99%พร้อมเปิด64แต่กลัวขัดนโยบาย|url=https://www.dailynews.co.th/bangkok/758012 |newspaper=Dailynews |date=17 July 2020}}</ref> By the end of September 2020, 21 sets had been delivered - 13 of the 6 car sets and 8 of the 4 car sets - with the final 4 sets to be delivered in October.<ref>{{cite news |title=สิ้นสุดรอคอย10ปี! ต.ค.นี้ทดสอบรถไฟฟ้าสีแดงตะวันตก|url=https://www.dailynews.co.th/economic/797227 |newspaper=Dailynews |date=24 September 2020}}</ref>

==Operation==
As of 2024, services operate from 5am to 12am with headways of 20 minutes.<ref>{{Cite web |title=ข้อมูลกำหนดเวลาเดินรถ |url=https://www.srtet.co.th/th/fare-timetable |access-date=2024-07-30 |website=www.srtet.co.th |language=th}}</ref> Distance-based fares range from 12 to 20 baht (previously 42 baht).<ref>{{Cite web |title=รฟฟท. ปรับค่าโดยสารรถไฟฟ้าสายสีแดง 20 บาท ตลอดสาย ตามนโยบายของรัฐบาล เริ่ม 16 ต.ค. 66 |url=https://www.srtet.co.th/th/news/detail/3745 |access-date=2024-07-30 |website=www.srtet.co.th |language=th}}</ref> The SRT also offers a 30 day integrated Transit Pass which can be used for 50 trips and for travel on all BMTA buses.

SRT long distance trains on the [[Southern Line (Thailand)|Southern Line]] terminating at Krung Thep Aphiwat share the same tracks.

===Ridership===
On the first full day of free trial operations on 3 August 2021 total passengers numbered 302, on 4 August this increased to 331 passengers.<ref>{{cite news |title=ตามคาด! รถไฟสายสีแดงผู้โดยสารบางตา เฉลี่ย 3,000 กว่าคน/วัน ใช้สถานีกลางบางซื่อมากสุด|url=https://mgronline.com/business/detail/9640000076858 |newspaper=Manager Online |date=5 August 2021}}</ref> By the end of September, this had increased to around 500-550 passengers a day.<ref>{{cite news |title=คลายเหงา!! รถไฟฟ้าสายสีแดงผู้โดยสารเกิน 5 พันคน
|url=https://www.facebook.com/TransportDailynews/posts/3010868955801269 |newspaper=Transport Daily News |date=28 September 2021}}</ref> For the first 10 months of operations to September 2022 both Red lines carried over 3.2 million passengers and services ran on time 99.45% of the time according to the SRT.<ref>{{cite news |title=รถไฟฟ้าสายสีแดงเผยครบ 10 เดือน ผู้โดยสารทะลุ 3.2 ล้าน|url=https://www.prachachat.net/general/news-1039773 |newspaper=Prachachat |date=6 September 2022}}</ref> However, a small percentage of this were passengers on the Light Red line. By the end of September 2022 the line averaged only 23,000 passenegers a month.<ref>{{cite news |title="คมนาคม" เปิดยอดผู้โดยสารสายสีแดง 3.9 ล้านคน ดึงรถเมล์ไฟฟ้าเชื่อมฟีดเดอร์|url=https://www.thansettakij.com/business/544565 |newspaper=Thansettakij |date=21 October 2022}}</ref> In November 2022, the SRT introduced regular DMU services from Thonburi via Taling Chan to Nakhon Pathom to connect with the Light Red line. Afterwards, daily passengers numbers rose significantly from an average of 300 a day to between 1400-1500 passengers a day in January 2023.<ref>{{cite news |title=สีแดงนิวไฮ! เกษตรแฟร์ดันสถานีบางเขนผู้โดยสารพุ่ง 4 เท่า ขึ้นปีที่ 2 ยอดสะสมทะลุ 5.3 ล้านคน|url=https://mgronline.com/business/detail/9660000011348 |newspaper=Manager Online |date=5 February 2023}}</ref>

==Future extensions ==
In July 2016, the cabinet approved the construction of the Bang Sue–Phaya Thai–Makkasan–Hua Mak segment.<ref>{{Cite web|url=http://bangkok.coconuts.co/2016/07/27/cabinet-gives-green-light-extension-light-red-line-dark-red-line-railway|title=Cabinet gives green light to the extension of Light Red Line, Dark Red Line railway|date=2016-07-27|website=Bangkok|access-date=2016-09-11}}</ref> However, the {{Cvt|15|km}}, 4 station western extension Taling Chan to Salaya was due to be tendered first by September 2018<ref name="bangkokpost.com">{{cite news |title=Ministry to forward plans for 2 Red Line extensions|url=https://www.bangkokpost.com/news/transport/1398170/ministry-to-forward-plans-for-2-red-line-extensions |newspaper=Bangkok Post |date=19 January 2017 }}</ref> and then slated for the 2nd half of 2019.<ref name="SRT eyeing B40bn budget">{{cite news |title=SRT eyeing B40bn budget|url=https://www.bangkokpost.com/business/tourism-and-transport/1691800/srt-eyeing-b40bn-budget |newspaper=Bangkok Post |date=9 June 2019}}</ref> However, the tender was further delayed until 2021 as the Transport Minister has requested the new Department of Railways to investigate conducting PPP tenders for this extension.<ref name="ศักดิ์สยาม เปิดปมทำไม รถไฟฟ้าสาย">{{cite news |title="ศักดิ์สยาม" เปิดปมทำไม "รถไฟฟ้าสายสีแดง" เลื่อนเปิดปี'64|url=http://www.prachachat.net/property/news-493750 |newspaper=Prachachat |date=19 July 2020}}</ref> The decision to change the extensions to PPP projects and tender out the operation of the line with a 50 year concession was opposed by the SRT and SRT union. On 10 February 2021, the Department of Railways announced that in April 2021 the SRT would issue the tenders for the west extensions to Salaya and from Taling Chan to Siriraj.<ref>{{cite news|date=10 February 2021|title=รฟท.เล็งเปิดประมูล "สายสีแดง" เม.ย.65|newspaper=Prachachat|url=https://www.thansettakij.com/content/Macro_econ/468178}}</ref> However, the PPP tender process was subject to further review.

In October 2021, the SRT announced that the PPP tenders would not be released until June 2022 with the aim to sign contracts for the extensions (with 50 year leases) in July 2023.<ref name="dailynews.co.th">{{cite news |title=มิ.ย.65 เปิดประมูล PPP รถไฟฟ้าสีแดง 1.8 แสนล้าน สร้างต่อขยายใหม่ 4 เส้น... สามารถติดตามต่อได้ที่|url=https://www.dailynews.co.th/news/413328 |newspaper=Dailynews |date=26 October 2021}}</ref> However, this was delayed yet again to an initial October 2022 tender release<ref>{{cite news |title=พร้อมประมูล ต.ค.นี้! รถไฟสีแดงต่อขยาย 3 เส้นทาง 2.3 หมื่นล้านบาท ส่วน Missing Link เร่งปรับแบบสถานีเชื่อมเข้า รพ.รามาฯ|url=https://mgronline.com/business/detail/9650000054293 |newspaper=Manager Online |date=8 June 2022}}</ref> and later a December 2022 date.<ref>{{cite news |title=รฟท. ลุยประมูลงานโยธา "ต่อขยาย" รถไฟสีแดง 4 เส้นทางก่อน PPP เดินรถม|url=https://www.dailynews.co.th/news/1372382/ |newspaper=Daily News |date=18 August 2022}}</ref> In late October 2022, the SRT again delayed the tender time frame to February 2023 with an aim to sign contracts by May 2023 but the time frame was contingent on new Cabinet approval of an updated budget for the extension.<ref>{{cite news |title=ขยายแน่ๆ! รถไฟฟ้าสายสีแดง 4 เส้นทาง 6.8 หมื่นล้าน เริ่มประมูลต้นปี 66 |url=https://www.dailynews.co.th/news/1623409/ |newspaper=Dailynews |date=28 October 2022}}</ref> At the same time, the SRT decided to defer the bidding for the 50 year operation concession and new EMUs to December 2024. Once the concession is contracted the SRTET will cease to operate the line.

With the 14 May 2023 national elections and the expected time frame 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 submitted to Cabinet in October 2023 for approval of a new budget of 10.67 billion baht to build the Salaya extension. If approved, a tender could be issued in the first quarter of 2024.<ref name="nationthailand.com">{{cite news |title=Transport Ministry to seek new Cabinet’s nod for 3 Red Line extensions |url=https://www.nationthailand.com/thailand/40028741 |newspaper=The Nation |date=21 June 2023 }}</ref>

Extensions for Phase II running from Taling Chan to Salaya and Phase III spur line from Taling Chan to Siriraj were approved by the Thai Cabinet on 17 June 2025. In addition, three infill stations of Rama VI Bridge, Bang Kruai (EGAT) and Ban Chim Phli were approved under a single construction contract totalling 20.5km. The proposal had been submitted to the Cabinet secretariat on 27 March 2025 and expects to open bidding in late-2025. The approved budget decreased from 16.847 to 15.176 billion baht, with construction projected to run from January 2026 to December 2028 and services beginning in 2029.<ref>{{cite web |url=https://www.bangkokbiznews.com/business/economic/1185249?|title=ครม.ไฟเขียวสร้างส่วนต่อขยาย 'รถไฟสายสีแดง' ประมูลทันทีปีนี้ |trans-title=Cabinet approves Red Line extension, to tender this year |work=BangkokBizNews |date=17 June 2025 |language=th |access-date=19 June 2025}}</ref>

Construction segments based on [[Mass Rapid Transit Master Plan in Bangkok Metropolitan Region|M-Map]]:<ref>{{cite web |url=http://mrt-progress.otp.go.th/MRT/?q=node/74 |title= แผนพัฒนาโครงข่าย &#124;|website=mrt-progress.otp.go.th |archive-url=https://web.archive.org/web/20110112163038/http://mrt-progress.otp.go.th/MRT/?q=node%2F74 |archive-date=2011-01-12}}</ref>
{| class="wikitable" width=50%
|-
!'''Phase'''
!'''Segment'''
!'''Length'''
!'''Progress'''
|-
| align=center| I
| Bang Sue–Taling Chan
| {{convert|15.26|km|mi|2|abbr=on}}
| Full operation: 29 November 2021
|-
| align=center| II
| Taling Chan–Salaya
| {{convert|14.8|km|mi|2|abbr=on}}
|  cabinet approval
|-
| align=center| III
| Taling Chan–Siraj
| {{convert|5.7|km|mi|2|abbr=on}}
|  cabinet approval

|- 
| align=center| IV
| Bang Sue–Hua Mak
| {{convert|20.14|km|mi|2|abbr=on}}
| Tender in late 2023
|- 
| align=center| V
| Salaya–Nakhon Pathom
| {{convert|30|km|mi|2|abbr=on}} 
| Planned long-term extension
|}

=== Phase II Taling Chan–Salaya Extension===
[[File:202402 Southern Line Junction at Taling Chan Station.jpg|thumb|End of electrification segment west of the [[Taling Chan Junction Railway Station]] (2024)]]
The SRT Light Red Line is planned to be extended by {{Cvt|14.8|km}} west to Salaya.<ref>http://www.siamlocalnews.com/anrt2553/view.php?gid=4033&newsid=6847&issueid=2064 {{Dead link|date=March 2022}}</ref> 4 stations are planned be built along the existing SRT corridor;<ref>http://www.siamlocalnews.com/anrt2553/view.php?gid=4033&newsid=6845&issueid=2064 {{Dead link|date=March 2022}}</ref>

{{ubl|1) Ban Chimphli station|2) Kanchanaphisek (Phutthamonthon Sai 2)|3) Sala Thammasop|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.<ref name="bangkokpost.com"/> This was then delayed to the 2nd half of 2019.<ref name="SRT eyeing B40bn budget"/> 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.<ref name="ศักดิ์สยาม เปิดปมทำไม รถไฟฟ้าสาย"/>

=== Infill stations ===
Two additional [[infill station]]s, Rama 6 bridge and Bang Kruay (EGAT) on either side of the Chao Praya river, were part of the original plans but deferred until ridership grew <ref>http://www.prachachat.net/news_detail.php?newsid=1356496581&grpid=&catid=19&subcatid=1900, 26 Dec 2012</ref> will be tendered as part of the 15&nbsp;km Salaya western extension tender.

=== Phase III Taling Chan–Siriraj spur line===
The SRT operates existing intercity services from Thonburi station to Kanchanaburi. 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 5.7&nbsp;km route:<ref>{{Cite news|url=http://www.prachachat.net/news_detail.php?newsid=1344342525&grpid=03&catid=00&subcatid=0000|title = ข่าวรอบวัน| newspaper=ประชาชาติธุรกิจ }}</ref> 
{{ubl|1) Taling Chan Floating Market station at Bang Ramat|2) Charansanitwongse station (interchange with the MRT Blue Line)|3) Thonburi/Siriraj station (interchange with the MRT Orange Line). 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 ===
The eastern extension will be {{Cvt|18.8|km}} long with stations at [[Ratchathewi Station|Ratchawithi]], [[Phaya Thai Station|Phaya Thai]], [[Makkasan Railway Station|Makkasan]], and [[Hua Mak Station (Airport Rail Link)|Hua Mak]]. It will have a narrow right of way given the current ARL viaduct and ARL stations.<ref>{{Cite news|url=https://mgronline.com/business/detail/9600000017426 |script-title=th:ทบทวนรถไฟสีแดง "Missing Link" เขตทางจำกัด-เปิดหน้าดินกระทบเดินรถหัวลำโพง |language=th}}</ref>

==Stations==
===Western stations===
{| class="wikitable" width=95%
|-align=center
|width=5%|'''Code'''
|width=21%|'''Station Name'''
|width=13%|'''Thai'''
|width=5%|'''Express Train'''
|width=5%|'''City Train'''
|width=40%|'''Transfer'''
|width=6%|'''Province'''
|-align=center bgcolor=#{{rcr|SRT Red Lines|Light Red}}
| colspan=7 |<span style="color:white;">'''''SRT Light Red Line'''''</span>
|- 
| align=center| RW01
| Bang Sue ([[Krung Thep Aphiwat Central Terminal|Krung Thep Aphiwat]])
| กรุงเทพอภิวัฒน์
| align=center| 
| align=center| 
| {{rint|bangkok|DarkRed}}<br />{{rint|bangkok|ARL}} (preliminary works)<br />{{rint|bangkok|Blue}}: [[Bang Sue MRT station|Bang Sue]]
| bgcolor="lightgrey" rowspan="3"|[[Bangkok]]
|- 
| align=center| RW02
| [[Bang Son railway station|Bang Son]]
| บางซ่อน
| align=center| 
| align=center| 
| {{rint|bangkok|Purple}}: [[Bang Son MRT station|Bang Son]]
|- bgcolor="lightgrey"
| align=center| RW03
| [[Phra Ram 6 station|Phra Ram 6]]
| พระราม 6
| align=center| 
| align=center| 
| 
|- bgcolor="lightgrey"
| align=center| RW04
| [[Bang Kruai-EGAT station|Bang Kruai-EGAT]]
| บางกรวย-กฟผ.
| align=center| 
| align=center| 
| 
|[[Nonthaburi Province|Nonthaburi]]
|- 
| align=center| RW05
| [[Bang Bamru railway station|Bang Bamru]]
| บางบำหรุ
| align=center| 
| align=center| 
|
| bgcolor="lightgrey" rowspan=5|[[Bangkok]]
|- 
| align=center| RW06
| [[Taling Chan railway station|Taling Chan]]
| ตลิ่งชัน
| align=center| 
| align=center| 
| {{rint|bangkok|Silom}}: Talingchan (proposed)
|- bgcolor="lightgrey"
| align=center| RW07
| [[Ban Chimphli station|Ban Chimphli]]
| บ้านฉิมพลี
| align=center| 
| align=center| 
| 
|- bgcolor="lightgrey"
| align=center| RW08
| [[Kanchanaphisek station|Kanchanaphisek]]
| กาญจนาภิเษก
| align=center| 
| align=center| 
| 
|- bgcolor="lightgrey"
| align=center| RW09
| [[Sala Thammasop station|Sala Thammasop]]
| ศาลาธรรมสพน์
| align=center| 
| align=center| 
| 
|- bgcolor="lightgrey"
| align=center| RW10
| [[Salaya Station|Salaya]]
| ศาลายา
| align=center| 
| align=center| 
| 
| rowspan=1|[[Nakhon Pathom Province|Nakhon Pathom]]
|-
|-align=center bgcolor=#{{rcr|SRT Red Lines|Light Red}}
| colspan=7 |<span style="color:white;">'''''Talingchan–Siriraj Branch Line'''''</span>
|-
| align=center| RW06
| [[Taling Chan railway station|Taling Chan]]
| ตลิ่งชัน
| align=center| 
| align=center| 
| {{rint|bangkok|Silom}}: Talingchan (proposed)
| bgcolor="lightgrey" rowspan="4"|[[Bangkok]]
|- bgcolor="lightgrey"
| align=center| RWS01
| [[Talat Nam Taling Chan station|Talat Nam Taling Chan]]
| ตลาดน้ำตลิ่งชัน
| align=center| 
| align=center| 
|
|- bgcolor="lightgrey"
| align=center| RWS02
| [[Charan Sanitwong station|Charan Sanitwong]]
| จรัญสนิทวงศ์
| align=center| 
| align=center| 
| {{rint|bangkok|Blue}}: [[Bang Khun Non MRT station|Bang Khun Non]]<br />{{rint|bangkok|Orange}}: Bang Khun Non (tender awarded)
|- bgcolor="lightgrey"
| align=center| RWS03
| [[Siriraj MRT station|Siriraj]]
| ศิริราช
| align=center|
| align=center| 
| {{rint|bangkok|Orange}}: Siriraj (tender awarded)
|-
|}
===Eastern stations===
{| class="wikitable" width=95%
|-align=center
|width=5%|'''Code'''
|width=21%|'''Station Name'''
|width=13%|'''Thai'''
|width=5%|'''Express Train'''
|width=5%|'''City Train'''
|width=40%|'''Transfer'''
|width=6%|'''Province'''
|-align=center bgcolor=#{{rcr|SRT Red Lines|Light Red}}
| colspan=7 |<span style="color:white;">'''''SRT Light Red Line'''''</span>
|- 
| align=center| RE01
| Bang Sue ([[Krung Thep Aphiwat Central Terminal|Krung Thep Aphiwat]])
| กรุงเทพอภิวัฒน์
| align=center| 
| align=center| 
| {{rint|bangkok|DarkRed}}<br />{{rint|bangkok|ARL}} (preliminary works)<br />{{rint|bangkok|Blue}}: [[Bang Sue MRT station|Bang Sue]]
| bgcolor="lightgrey" rowspan="9"|[[Bangkok]]
|-
|- bgcolor="lightgrey"
| align=center| RE02
| [[Pradiphat station|Pradiphat]]
| ประดิพัทธ์
| align=center| 
| align=center| 
| {{rint|bangkok|DarkRed}} (approved)
|- bgcolor="lightgrey"
| align=center| RE03
| [[Sam Sen station|Sam Sen]]
| สามเสน
| align=center| 
| align=center| 
| {{rint|bangkok|DarkRed}} (approved)
|- bgcolor="lightgrey"
| align=center| RE04
| [[Ratchawithi station|Ratchawithi]]
| ราชวิถี
| align=center| 
| align=center| 
| {{rint|bangkok|DarkRed}} (approved) 
|- bgcolor="lightgrey"
| align=center| RE05
| [[Phaya Thai station|Phaya Thai]]
| พญาไท
| align=center| 
| align=center| 
| {{rint|bangkok|Sukhumvit}}: [[Phaya Thai BTS station|Phaya Thai]]<br />{{rint|bangkok|ARL}}: [[Phaya Thai Airport Link station|Phaya Thai]]
|- bgcolor="lightgrey"
| align=center| RE06
| Makkasan
| มักกะสัน
| align=center| 
| align=center| 
| {{rint|bangkok|ARL}}: [[Makkasan station|Makkasan (City Air Terminal)]]<br />{{rint|bangkok|Blue}}: [[Phetchaburi MRT Station|Phetchaburi]]
|- bgcolor="lightgrey"
| align=center| RE07
| [[Sun Wichai station|Sun Wichai]]
| ศูนย์วิจัย
| align=center| 
| align=center| 
| {{rint|bangkok|Grey}} (proposed)
|- bgcolor="lightgrey"
| align=center| RE08
| [[Ramkhamhaeng station|Ramkhamhaeng]]
| รามคำแหง
| align=center| 
| align=center| 
| {{rint|bangkok|ARL}}: [[Ramkhamhaeng station (Airport Rail Link)|Ramkhamhaeng]]
|- bgcolor="lightgrey"
| align=center| RE09
| [[Hua Mak Railway station|Hua Mak]]
| หัวหมาก
| align=center| 
| align=center| 
| {{rint|bangkok|ARL}}: [[Hua Mak railway station|Hua Mak]]<br />{{rint|bangkok|Yellow}}: Hua Mak
|}

== Network map ==
{{Wide image|2023versionofbangkokmassrapidtransitmap.png|700px}}

==See also==
{{Div col|colwidth=20em}}
* [[Mass Rapid Transit Master Plan in Bangkok Metropolitan Region]]
* [[SRT Dark Red Line]]
* [[Airport Rail Link (Bangkok)]]
* [[MRT (Bangkok)]]
* [[MRT Blue Line]]
* [[MRT Brown Line]]
* [[MRT Grey Line]]
* [[MRT Light Blue Line]]
* [[MRT Orange Line]]
* [[MRT Pink Line]]
* [[MRT Purple Line]]
* [[MRT Yellow Line]]
* [[BTS Skytrain]]
* [[BTS Sukhumvit Line]]
* [[BTS Silom Line]]
* [[Bangkok BRT]]
* BMA [[BMA Gold Line|Gold Line]]
{{Div col end}}

==References==
{{reflist}}

==External links==
{{Commons category|SRT Light Red Line}}
* [http://www.railway.co.th/resultproject/project_redline.asp?redline=5301201 "SRT Red Line website"]
* [https://www.bts.co.th/eng/routemap.html Airport Rail Link, BTS, MRT & BRT network map]

{{Bangkok Rapid Transit stations
|LightRed=yes
}}
{{Public transport in Bangkok}}
{{State Railway of Thailand}}
{{Urban Rail Transit in ASEAN}}

[[Category:SRT Red Lines|Light]]
[[Category:Bangkok Commuter rail lines]]