MRT Purple Line
J-TRECsustina trainset
Overview
Other name	MRT Chalong Ratchadham Line
Native name	สายสีม่วง สายฉลองรัชธรรม
Owner	Mass Rapid Transit Authority
Locale	Nonthaburi Province and Bangkok
Termini	PP01Khlong Bang Phai PP16Tao Poon
Stations	Total : 33 stations 16(operational) 17(under construction)
Color on map	Purple
Service
Type	Rapid transit
System	MRT
Operator(s)	Bangkok Expressway and Metro
Depot(s)	Khlong Bang Phai Kru Nai(under construction)
Rolling stock	J-TREC Sustina S24-EMU : 21 three-car trainsets
Daily ridership	66,935(๋2024)
History
Commenced	10 November 2009; 15 years ago (2009-11-10)
Opened	6 August 2016; 9 years ago (2016-08-06)
Technical
Line length	Total :43.70 km (27.15 mi) 20.92 km (13.00 mi)(operational) 22.78 km (14.15 mi)(under construction)
Number of tracks	2
Character	Elevated: 30.63 km (19.03 mi) Underground : 13.07 km (8.12 mi)
Track gauge	1,435 mm (4 ft 8+1⁄2 in)standard gauge
Electrification	750 V DC third rail
Operating speed	80 km/h (50 mph)
Signalling	BombardierCITYFLO 650 moving blockCBTCATC underATO GoA 2 (STO), with subsystems ofATP, ATS andCBI[1]
Route map Legend PP1 Khlong Bang Phai To Main Depot PP2 Talad Bang Yai PP3 Sam Yaek Bang Yai PP4 Bang Phlu PP5 Bang Rak Yai PP6 Bang Rak Noi Tha It PP7 Sai Ma Chao Phraya River PP8 Phra Nang Klao Bridge PP9 Yaek Nonthaburi 1 PP10 Bang Krasor  MRT Pink Line: Min Buri PP11 Nonthaburi Civic Center PP12 Ministry of Public Health PP13 Yaek Tiwanon PP14 Wong Sawang  SRT Light Red Line: Taling Chan – Bang Sue PP15 Bang Son PP16 Tao Poon  MRT Blue Line: Tha Phra – Bang Sue Parliament House Sri Yan Vajira Hospital National Library Bang Khun Phrom Democracy Monument  MRT Orange Line: Taling Chan – Min Buri Sam Yot  MRT Blue Line: Bang Khae – Hua Lamphong Chao Phraya River Memorial Bridge  SRT Dark Red Line: Maha Chai – Hua Lamphong Wongwian Yai BTS  BTS Silom Line: Bang Wa – Siam Somdech Phra Pinklao Hospital Dao Khanong Bang Pakaeo Bang Pakok Yaek Pracha Uthit Rat Burana Phra Pradaeng Khru Nai

TheMRT Purple line (Thai:รถไฟฟ้ามหานคร สายสีม่วง) orMRT Chalong Ratchadham line (Thai:รถไฟฟ้ามหานคร สายฉลองรัชธรรม) is Bangkok'sfifth rapid transit line, following theSukhumvit Line,Silom Line,Blue Line, andAirport Rail Link. The line is 23 km (14 mi) long,^[2] serving the north-western area of Bangkok running fromTao Poon toKhlong Bang Phai inNonthaburi Province.

The Northern section of the line opened on 6 August 2016, with travel between Khlong Bang Phai and Tao Poon.^[3][2] It is the second line ofMRT system and is operated byBEM under a concession contract. Daily ridership is 70,000.^[4][5]

A 23.63 km (14.68 mi), 17 station Southern extension of the line between Tao Poon and Kru Nai consisting of a 14.3 km (8.89 mi) underground section and a 9.3 km (5.78 mi) elevated section^[6] commenced construction in August 2022. As of April 2025, construction has progressed to 53.4% completion with an expected opening date of 2028.^[7]

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The Purple line starts fromKhlong Bang Phai station inBang Bua Thong District. The line travels south along Kanchanaphisek Road before turning eastward nearCentral WestGate, ontoRattanathibet Road. It continues along Rattanathibet Road, passing through a large residential area inBang Yai District and crosses theChao Phraya River on a bridge parallel to thePhra Nang Klao Bridge and runs towardsNonthaburi Civic Center station. The line then turns southward onto Tiwanon Road, passing theMinistry of Public Health and turns southeast onto Krung Thep-Nonthaburi Road, enteringYaek Tiwanon station. The line then enters Bangkok city limits at Bang Sue district and passesBang Son station before terminating at the upper platforms ofTao Poon station, with a total length of 23 kilometres (14.29 mi), serving 16 stations.

Officially named the Chalong Ratchadham Line (Thai:สายฉลองรัชธรรม) – "To Celebrate the Great King's Reign with Righteousness"^[8] – but informally known as the "Purple Line", the rapid transit line provides a north–western corridor inBangkok's Mass Rapid Transit Master Plan. The line also incorporated an extension of the Blue Line from nearbyBang Sue station toTao Poon Station.

In the 1990s, the plan for the Purple Line was to run from Bang Phut to Bang Sue for 12 kilometres (7.5 mi), with an extension toThewet for 6.7 kilometers (4.2 mi).^[9]

This line was created from the adjustment of the 1994 mass transit rail system master plan, which connected the original extension of the Blue Line from Tao Poon to Bang Yai, while the original Purple Line would have run from the National Library to Tao Poon and the originalOrange Line from Samsen (National Library) to Rat Burana, becoming a new line designated as the Purple Line, included in the master plan of the Office of Transport and Traffic Policy and Planning (OTP) for the first time in 2004. Five years later, the line's construction began.

Construction was divided into six contracts, three of them for civil works. The contracts were signed from late 2009 to early 2010 and completion was originally scheduled for the end of 2014.^{[10][11][12][13]} The third contract included construction of fourpark and ride buildings at theKhlong Bang Phai,Sam Yaek Bang Yai,Bang Rak Noi Tha It, andYaek Nonthaburi 1 stations. On 31 March 2017, the fifth contract was effectively terminated and became part of a new Blue Line concession agreement.^[14][15]

The 2011 Thailand floods delayed the construction of the line for nearly one year. In June 2013, five people were injured when six beams fell onto vehicles below Tao Poon station.^[16] In July 2014, the civil work was 94 percent complete;^[17][18] in October 2014, civil work was stated to be 99% complete.^[19]

The line opened on 6 August 2016, when His Majesty KingBhumibol Adulyadej graciously appointed Her Royal HighnessPrincess Maha Chakri Sirindhorn to represent him in presiding over the opening ceremony and officially pressing the button to open the electric train system.^[3][20] However, the MRT Blue Line extension to Tao poon was delayed, so when it opened the Purple Line couldn't interchange with the Blue line as planned. This resulted in low line usage. Even with a reduced fare, the line only attracted about 22,000 passengers daily compared to a goal of 100,000. A shuttle bus service was in operation betweenTao Poon MRT station andBang Sue MRT station to connect with the Blue Line.^[21] When the Blue line extension finally opened a year later, on 11 August 2017,^[22][23] ridership significantly increased. In 2019, daily ridership was 70,000.^[4][5]

As the northern section of the Purple line was built first, the second phase of the Purple Line south from Tao Poon via Rattanakosin - Bangkok's old town to Rat Burana would fully complete the line. The length of the southern extension is 23.63 km (14.68 mi) (14.29 km (8.88 mi) underground, 9.34 km (5.80 mi) elevated with 17 stations - ten underground and seven elevated).^[6] The initial cost of the southern extension is 82 billion baht and with a planned opening by the end of 2027.^[31]

The Thai Cabinet was expected to approve the tender in mid 2017 with a tender then to be issued in the second half of 2017.^[32] On 25 July 2017, Cabinet approval was given,^[33][34] but the tender was then delayed until 2018.^[35][36] By December 2018, a tender had still not been issued and was further delayed.^[37] In August 2019, subject to final land acquisition, a March 2020 tender was planned.^[38] In mid 2020, the Ministry of Transport still aimed for a tendering process within 2020 despite COVID-19 related delays.^[39] The MRTA then expected to issue a tender in February 2021.^[40] and if construction had begun in 2021, the extension was projected to enter service sometime in 2027.^[41] However, the tender was delayed yet again and subsequently cancelled in August 2021 until it was finally issued in November 2021.^[42]

Construction contracts were signed on 11 March 2022 with a construction period of 2005 days for a planned 2027 opening date.^[43]

Contactors were issued with a Notice to Proceed on 25 April 2022 giving them access to sites along the route with actual construction planned to begin from August 2022.^[44] Construction began in early August for two contract sections, 3 & 4.^[45] Some 410 lots and 500 buildings will need to be appropriated to build the extension and as of May 2022 many of them were still to be surveyed.^[31]

Construction progress was at 3.45% complete at the end of September 2022.^[46] By the end of November 2022, construction progress was at 4.30%.^[47] At the end of February 2023, construction had progressed to 7.73%.^[48]

By the end of May 2023, construction had progressed to 11.50%.^[49]

As of December 2024, construction has progressed to 46.3% completion.^[50]

As of June 2025, construction has progressed to 57.6% completion with an expected opening date of 2028.^[7]

In August 2025, it's reported that only the section between Parliament House station and National Library station will open in 2027. The opening date for the whole extension is delayed to 2030.^[51][52]

On 24 September 2025, at approximately 07:13 local time, a sinkhole measuring about 20 metres in depth opened on a section of Samsen Road in Bangkok. The incident occurred near the construction site of Vajira Hospital Station, part of the southern section of the MRT Purple Line.^[53]

Following the collapse, the MRTA suspended construction activities at the affected site to investigate the cause of the incident.^[54]

Code	Station Name		Image	Opened	Platform Type	Position	Park & Ride	Transfer	Notes
	English	Thai
Khlong Bang Phai -Tao Poon: 20.92 km(operational)
PP01	Khlong Bang Phai	คลองบางไผ่		6 August 2016; 9 years ago (2016-08-06)	Island	Elevated	√		Exit to: • Khlong Bang Phai Depot • DHL Supply Chain & Distribution
PP02	Talad Bang Yai	ตลาดบางใหญ่			Island		-		Exit to: • Big C Extra Bangyai • The Square Bang Yai • Kasemrad International Hospital Ratthanathibet • Home Pro Rattanathibet • Big C Supercenter Rattanathibet 1 • Decathlon Bangyai • Index Living Mall Bang Yai •Central Westgate • IKEA Bangyai • Bang Yai Market
PP03	Sam Yaek Bang Yai	สามแยกบางใหญ่			Island		√
PP04	Bang Phlu	บางพลู			Island		-		Exit to Megahome Rattanathibet
PP05	Bang Rak Yai	บางรักใหญ่			Island		-		Exit to Wat Bang Rak Yai
PP06	Bang Rak Noi Tha It	บางรักน้อย-ท่าอิฐ			Island		√	Proposed connecting station to BTS (future)
PP07	Sai Ma	ไทรม้า			Island		-
PP08	Phra Nang Klao Bridge	สะพานพระนั่งเกล้า			Island		-	Connecting station, without paid-area integration to Phra Nang Klao pier for • Mine Smart Ferry  • CHAOPHRAYA EXPRESS	Exit to: • Wat Noi Nok • Wat Chaeng Sirisamphan • Tonsak Market • Rajamangala University of Technology Suvarnabhumi - Nonthaburi Campus - North Area
PP09	Yaek Nonthaburi 1	แยกนนทบุรี 1			Island		√		Exit to: •Central NorthVille (was known as Central Rattanathibet) • Owl Market
PP10	Bang Krasor	บางกระสอ			Island		-		Exit to: • Big C Supercenter Rattanathibet 2 • Grand Richmond Stylish Convention Hotel Formerly Si Phon Sawan
PP11	Nonthaburi Civic Center	ศูนย์ราชการนนทบุรี			Island		-	Connecting station, without paid-area integration, to • MRT  , via a 350-metre elevated pedestrian walkway. • MRT (future)	Exit to: • National Broadcasting and Telecommunications Commission • Nonthaburi Civic Center • Esplanade Cineplex Ngamwongwan – Khae Rai • Siam Business Administration Nonthaburi Technological College • Makut Rommayasaran Park
PP12	Ministry of Public Health	กระทรวงสาธารณสุข			Island		-		Exit to: •Ministry of Public Health •Srithanya Hospital • Regional Revenue Office 4
PP13	Yaek Tiwanon	แยกติวานนท์			Island		-
PP14	Wong Sawang	วงศ์สว่าง			Island		-		Exit to Big C Market Place Wong Sawang
PP15	Bang Son	บางซ่อน			Island		-	Connecting station, without paid-area integration, to • SRT  •SRT Southern Line	Exit to Bang Son Market
PP16	Tao Poon	เตาปูน			Island		-	Interchange station to MRT	Exit to: • Tao Poon Market • Lotus's Prachachuen
Tao Poon - Kru Nai: 22.78 km(under construction)
PP17	Parliament House	รัฐสภา	-	2030; 5 years' time (2030) (expected)[51][52]	Island	Underground	-		Exit to: •Thai Parliament • Defence Industrial Department • 4th Armoured Regiment, 1st Division King's Royal Guard • Air Defence Division • Wat Mai Thongsen • Wat Kaew Fah Chulamanee
PP18	Sri Yan	ศรีย่าน	-		Stacked		-		Exit to: • Supreme Complex • Makro Samsen • Royal Irrigation Department • Medium Irrigation Water Resources Development Division • Wimol Sriyan Commercial College Formerly Royal Irrigation Department.[56]
PP19	Vajira Hospital	วชิรพยาบาล	-		Stacked		-		Exit to: •Vajira Hospital •Sukhothai Palace • Market Place Dusit • Suan Dusit University •Saint Gabriel's College
PP20	National Library	หอสมุดแห่งชาติ	-		Side		-		Exit to: • Suan Sunandha Rajabhat University •National Library of Thailand • Rajamangala University of Technology Phra Nakhon •Thewet, Wat Thewarat Kunchorn
PP21	Bang Khun Phrom	บางขุนพรหม	-		Stacked		-		Exit to: •Bank of Thailand •Bank of Thailand Museum •Bang Khun Phrom Palace • Wat Sam Phraya
PP22	Democracy Monument	อนุสาวรีย์ประชาธิปไตย	-		Stacked		-	Interchange station to MRT (under construction)	Exit to: • Mahakan Fort • Rattanakosin Exhibition Hall •Queen Sirikit Gallery • Royal Pavilion Mahajetsadabadin •Wat Saket Formerly Phan Fa
PP23	Sam Yot	สามยอด			Island		-	Interchange station to MRT	Exit to: •Giant Swing (includingWat Suthat and Wat Dev Mandir) •Khlong Ong Ang • Mega Plaza Saphan Lek •Phahurat •Rommaninat Park •The Old Siam Plaza
PP24	Memorial Bridge	สะพานพุทธฯ	-		Island		-	Proposed connecting station to Prachathipok station for MRL	Exit to: •Suksanari School •Wat Prayurawongsawat Worawihan •Wat Phitchaya Yatikaram Worawihan •Wat Anongkharam Worawihan • Big C Supercenter Itsaraphap
PP25	Wongwian Yai	วงเวียนใหญ่	-		Island		-	Connecting station, without paid-area integration to • BTS  via 270-metre underground walkway • SRT  via 120-metre covered walkway(future)	Exit to: • Wongwian Yai Market •Wongwian Yai
PP26	Somdech Phra Pinklao Hospital	โรงพยาบาลสมเด็จพระปิ่นเกล้า	-		Island		-		Exit to: •Somdech Phra Pinklao Hospital • Samre Market Formerly Samre
PP27	Dao Khanong	ดาวคะนอง	-		Side	Elevated	-		Exit to: • Big C Supercenter Dao Khanong • Wat Mongkhon Wararam
PP28	Bang Pakaeo	บางปะแก้ว	-		Side		-
PP29	Bang Pakok	บางปะกอก	-		Side		√		Exit to: • Wat Bang Pakok • Bang Pakok Wittayakom School • Bangpakok 1 Hospital • Bang Pakok Fresh Market • Lotus's Bangpakok
PP30	Yaek Pracha Uthit	แยกประชาอุทิศ	-		Side		-		Exit to: • Bangkok Employment Office Area 2 • Han Clan Foundation of Thailand • Wat Sarod School • Wat Sarod Formerly Rama 9 Bridge
PP31	Rat Burana	ราษฎร์บูรณะ	-		Side		√
PP32	Phra Pradaeng	พระประแดง	-		Side		-		Exit to: • Phra Pradaeng Arcade Market • HomePro Suk Sawat • Big C Supercenter Suksawat • Thaiwatsadu Suk Sawat
PP33	Khru Nai	ครุใน	-		Side		-		Exit to Wat Kru Nai

^[2]

The Khlong Bang Phai Depot serves as the main maintenance facility for the entire MRT Purple Line. It is onKanchanaphisek Road, nearKhlong Bang Phai Station. Additionally, the Kru Nai stabling yard is currently under construction as part of the Purple Line Southern Section project. It is near the southern section ofKanchanaphisek Road inPhra Pradaeng District,Samut Prakan Province.

There are currently four Park & Ride facilities along the MRT Purple Line, atKhlong Bang Phai,Sam Yaek Bang Yai,Bang Rak Noi Tha It, andYaek Nonthaburi 1 stations. Two additional facilities are under construction atBang Pakok andRat Burana stations as part of the Purple Line Southern Section project.

The MRT Purple Line comprises 33 stations, with 16 currently in operation since 2016—all of which are elevated. The remaining 17 stations are under construction and expected to be completed by 2029, consisting of 10 underground and 7 elevated stations.

Station structures on the MRT Purple Line North Section range from 300 to 400 meters in length and approximately 18 meters in width. In the Southern Section, underground stations typically measure 250 meters in length and 20 meters in width, while elevated stations are 153 meters long and 25 meters wide. All stations are designed to accommodate a maximum of six cars per train. Elevated stations are equipped with half-height platform screen doors, while underground stations will be fitted with full-height platform screen doors. In addition, the entrances to the stations are designed to be about one meter above ground level, taking into account the highest recorded flood levels in Bangkok to prepare for potential future flooding events.

In November 2013, BEM contracted withMarubeni Corp,Toshiba Corp, andEast Japan Railway Company to install E&S systems, supply 21 three-car trains (total of 63 cars) rolling stock, and provide maintenance for 10 years as part of a contract worth 12.6 billion baht.^[57] East Japan Railway train manufacturing subsidiaryJ-TREC built them in Yokohama with the first sets delivered in early 2016.^[58] The trains are owned by the MRTA which paid for the rolling stock at BEMs request.^[38] The southern extension will acquire 17 additional trains, along with the current ones, to create a total of 38 trains.

In total, line is service by 21 three-car trains.^[8] Trains are powered by 750 V DC via third rail system, are air-conditioned and capable of traveling at up to 80 km/h (50 mph).

• 
  MRT Purple Line train entering a station.
• 
  Purple Line train spotted nearCentral WestGate.
• 
  Interior of a train.
• 
  Interior of a train.
• 
  Dynamic route map
• 
  Platform Level atBang Phlu station

Bombardier Cityflo 650 signaling system has been implemented for the MRT Purple Line project. Thiscommunication-based train control (CBTC) system supportsautomatic train operation (ATO), allowing for efficient and safe control of train movements. It enables real-time train monitoring, optimizing operations and minimizing delays while prioritizing passenger safety. Additionally, the system ensures a minimum headway of just ninety seconds.^[59]

The line operates with varying schedules across stations. The first train departs fromKhlong Bang Phai station at 5:30 AM and fromTao Poon station at 6:00 AM. The frequency of train services depends on the time of day and passenger volume. The service hours are determined by the departure time of the last train heading toKhlong Bang Phai station. For example, when the last train departs fromTao Poon station at 11:24 PM, that marks the closing time for all stations, with the final closure occurring atTalad Bang Yai Station.

When the Purple line first opened daily ridership was only 22,000 compared to projected numbers of 100,000.^[61] After the opening of the Blue Line extension to Tao Poon 1 year later in August 2017, daily average ridership increased significantly from 33,000 to 50,000.^[62]

In August 2018, the MRTA Deputy Governor stated that daily ridership had increased to 60,000 each weekday.^[63] By late 2019, this had increased to 70,000.^[4] In 2023 the purple line saw an average of 50385 passengers per day.^[64]

On 16 October 2023, MRT Purple Line began using the new fare rates of 14 to 20 baht (down from 16 to 42 baht) after the '20 Baht Transit Max Fares Policy' was approved by the Thai government.^[65]

From 25 January to 31 January 2025, Prime MinisterPaetongtarn Shinawatra implemented a policy of free public transportation in Bangkok for one week. This measure aimed to address the worsening air pollution caused by surging dust levels across all districts of the capital.^[66]

MRT Purple Line fare is calculated based on the travel distance between the origin and destination stations. Previously, fares ranged from 14 to 42 baht, with a maximum of 70 baht when transferring to the MRT Blue Line. Following the introduction of the 20-baht fare policy in October 2023, fares were reduced to a range of 14 to 20 baht, with a new maximum of 51 baht when transferring to the Blue Line. Discounted fares are available for children under 14 and senior citizens, starting at 7 baht and capping at 36 baht with a Blue Line transfer. Student fares now start at 13 baht and rise to 48 baht when including a transfer to the Blue Line.

Starting on 30 November 2023, passengers using a credit or debit card, Visa, or Mastercard will receive a 20 baht discount when transferring to theLight Red Line, capping the maximum fare between the two lines at 20 baht.^[72] In 2024, passengers will also receive a 15 baht discount when transferring from the Purple Line to thePink Line, and a 14 baht discount when transferring in the opposite direction. Senior citizens are eligible for an 8 baht discount when transferring from the Purple Line to thePink Line, and a 7 baht discount when transferring from thePink Line to the Purple Line. Students will receive a 15 baht discount when transferring from the Purple Line to thePink Line, and a 13 baht discount when transferring from thePink Line to the Purple Line.^[73]

On March 28, a7.7-magnitude earthquake in Myanmar struck Bangkok, leading to the temporary suspension of all train services to ensure readiness for resumption and to prepare for potential aftershocks. The line resumed normal service on the next day.^[74]

On 24 September 2025, a section ofSamsen Road collapsed, creating a largesinkhole in front ofVajira Hospital. The hole was estimated to be about 30 metres wide and nearly 50 metres deep, swallowing several vehicles and damaging water pipes, power lines, and other infrastructure. Although no injuries were reported, parts of the Sam Sen police station and nearby buildings were evacuated, and the hospital suspended some services for two days as a precaution.

Officials linked the collapse to soil erosion associated with the construction of the MRT Purple Line South section and a possible leakage from water pipes beneath the road. Initial repair work involved pouring large amounts of concrete into the cavity, but engineers were forced to stop when the material began seeping into a nearby tunnel through a breach in its wall. By the following day, the ground continued to shift, complicating stabilization efforts. Authorities responded by closing off the area, installing monitoring equipment, and preparing plans for a permanent retaining wall.

TheBangkok Metropolitan Administration stated that full repairs would require thousands of tonnes of concrete and additional engineering measures. Inspections of surrounding structures are ongoing, and traffic on Samsen Road is expected to resume by 9 October 2025.^{[75][76][77][78]}

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