MRT Purple Line
J-TREC Sustina trainset
|Locale||Nonthaburi Province and Bangkok|
|Termini||Khlong Bang Phai
|Opened||6 August 2016|
|Owner||Mass Rapid Transit Authority|
|Operator(s)||Bangkok Expressway and Metro Public Company Limited|
|Depot(s)||Khlong Bang Phai|
|Line length||23 km (14 mi)|
|Number of tracks||2|
|Track gauge||1,435 mm (4 ft 8 1⁄2 in)|
|Operating speed||80 km/h (50 mph)|
The MRT Purple line (Thai: รถไฟฟ้ามหานคร สายสีม่วง), officially the MRT Chalong Ratchadham line (Thai: รถไฟฟ้ามหานคร สายฉลองรัชธรรม), is a rapid transit line of Bangkok's Metropolitan Rapid Transit system for the Mass Rapid Transit Authority of Thailand (MRTA) in the Bangkok Metropolitan Region and Nonthaburi Province. It opened for service on 6 August 2016 and is the second MRT line operated by BEM (formerly BMCL) and the city's fifth rapid transit line, following the Sukhumvit Line, Silom Line, MRT Blue Line, and Airport Rail Link.
A 23.6km Southern extension from Tao Poon to Rat Burana via Wong Wian Yai was approved for tender by the Thai Cabinet on 25 July 2017. The tender was due to be out in late 2017, but has been delayed until 2018. If construction commences in the second half of 2018, the extension will open in 2024.
The Purple Line serves travellers between the northwestern suburbs of Bangkok in Nonthaburi Province and the southern area of Thonburi in Rat Burana District. It runs through downtown along Samsen Road, passing the Rattanakosin old quarter and historical places in Dusit and Phra Nakhon District: the national library, Thewet market, Bang Lamphu, the Democracy Monument, the Golden Mount, Phahurat, the Memorial Bridge, and the Wongwian Yai roundabout. It will also serve the new Thai parliament at the Kiak Kai intersection. This is the first Bangkok metro line into an adjacent province: the northern terminus, Khlong Bang Phai Station, is in Bang Bua Thong, Nonthaburi Province.
The line is divided into two sections, 23 km from Tao Poon - Khlong Bang Phai, which is operational, and 19.8 km from Tao Poon - Rat Burana. The first section was originally scheduled to be open in late 2014, but the opening was delayed until August 2016.
When the Purple line opened, a 1.2 kilometre 'missing link' between the Purple Line's terminus at Tao Poon and the MRT Blue line at Bang Sue existed leading to inter-connectivity problems for passengers. The extension of the Blue Line from Bang Sue to Tao Poon finally opened 1 year later on August 11, 2017. Before then, passengers had to take shuttle buses to transfer between the two lines. The missing link was blamed for initial low ridership, with only 22,000 daily passengers compared to projected numbers of 100,000. After the opening of the Blue Line extension to Tao Poon on 11 August 2017, daily average ridership increased significantly from 33,000 to 50,000. 
The line is indicated by the colour purple on network maps.
The Tao Poon - Khlong Bang Phai section starts from the Tao Poon elevated station at Tao Poon junction, where it transfers to the MRT Blue Line extension. It runs north on a viaduct along Krung Thep-Nonthaburi Road, providing transfer to the Red commuter railway at Bang Son railway station, and approaches Mueang Nonthaburi District of Nonthaburi Province. The line goes further north via Tiwanon Road, passes the Ministry of Public Health, then turns at the Khae Rai junction to west Nonthaburi via Rattanathibet Road, passes the Nonthaburi Government Centre, crosses the Chao Phraya River on a viaduct parallel to the Phra Nangklao Bridge. Then it continues to a large residential area in Bang Yai District and turns to the north along Kanchanaphisek Road, passes Bang Yai market, and terminates at Khlong Bang Phai in Bang Bua Thong District. The total length is 23 kilometres (14 mi).
Construction is divided into three separate contracts. The first covers Bang Sue - Tao Poon - Phra Nangklao Bridge, a distance of 12 km, with nine stations. This contract includes construction of a 1.2 km extension of the MRT Blue Line from Bang Sue to Tao Poon where the Blue Line and the Purple Line will interchange.
The second contract covers the Phra Nangklao Bridge (including a new bridge) - Bang Yai District - Khlong Bang Phai terminus, with a length of 11 km and seven stations. The third contract is for the construction of a train depot at the Bang Yai terminus and four park and ride buildings at Khlong Bang Phai, Sam Yaek Bang Yai, Tha It, and the Yaek Nonthaburi stations.
|1||Bang Sue-Tao Pun to Phra Nangklao Bridge||12|
|2||Phra Nangklao Bridge to Khlong Bang Phai terminus (river crossing viaduct included)||11|
|3||Depot at Khlong Bang Phai, four park and ride stations|
|4||Rolling Stock and Management - BMCL (Joint Development)|
|5||Signalling and Electrical - Bang Yai to Taopoon|
In September 2013, BEM (operator of the MRT Blue Line) signed an 82.6 billion baht contract with the MRTA for the procurement of rolling stock, installation of E&S systems, and operation and maintenance of the Purple Line. The concession is for a 30-year period.
The sixth contract, which was due to be awarded in mid-2011 for the laying of track was delayed for over one year due to internal disputes within the MRTA and uncertainty about the bidding process. However, this contract was finalised in October 2012.
In October 2012, BEM, private operator of the MRT Blue line, was granted a 30-year concession to operate the Purple Line and supply rolling stock and electrical systems.
In November 2013, BEM contracted with Marubeni Corp, Toshiba Corp, and East Japan Railway Company to install E&S systems, supply 63 cars of rolling stock, and provide maintenance for 10 years as part of a contract worth 12.6 billion baht.
In the table below, names in italics indicate that the station is under construction and not yet in operation.
|Khlong Bang Phai||คลองบางไผ่||P1||-||2||Bang Bua Thong||Nonthaburi|
|Talad Bang Yai||ตลาดบางใหญ่||P2||1.27||2|
|Sam Yaek Bang Yai||สามแยกบางใหญ่||P3||1.56||2|
|Bang Rak Yai||บางรักใหญ่||P5||1.20||2|
|Bang Rak Noi Tha It||บางรักน้อย-ท่าอิฐ||P6||1.25||2||Mueang Nonthaburi|
|Phra Nangklao Bridge||สะพานพระนั่งเกล้า||P8||1.47||2|
|Yaek Nonthaburi 1||แยกนนทบุรี 1||P9||1.63||2|
|Nonthaburi Civic Centre||ศูนย์ราชการนนทบุรี||P11||0.90||2||MRT Pink Line (under construction)
MRT Brown Line (planned)
|Ministry of Public Health||กระทรวงสาธารณสุข||P12||1.79||2|
|Wong Sawang||วงศ์สว่าง||P14||1.72||2||Bang Sue||Bangkok|
|Bang Son||บางซ่อน||P15||1.29||2||SRT Light Red Line (Line not operational)|
|Tao Poon||เตาปูน||P16||1.58||4||MRT Blue Line|
Phase 2, South: The proposed extension from Tao Pun - Rat Burana will run south through Bangkok's old quarter from Tao Pun junction on a viaduct. It then will go into an underground structure along Sam Sen Road, passing the new Thai parliament site, and transfers to the proposed Red inner-city shortcut commuter at Sanghi intersection. It passes the national library in Dusit District before it reaches Phra Nakhon District at Thewet Market. The line turns east at Bang Lamphu and goes along the city moat to the south, with transfers possible to the planned MRT Orange Line at Ratchadamnoen Road near the Democracy Monument. It passes Golden Mount before possible transfers to the southern extension of the Blue Line at Wang Burapha near Yaowarat Road in Chinatown and the Phahurat textile market.
The line crosses the Chao Phraya River near the Memorial Bridge towards the Wongwian Yai roundabout in Thonburi on the west bank, with possible transfers to the Dark Red Line commuter and to Wongwian Yai BTS Station. It continues south to Chom Thong, then on an elevated structure for 5.5 kilometres (3.4 mi) and ends in Rat Burana District, a short distance to the nearby Phra Pradaeng suburban town in Samut Prakan Province. The total length will be about 23.6 km, including ten underground and seven elevated stations.
The Cabinet was expected to approve the Purple Line Southern extension in mid 2017 with a tender due in the 2nd half of 2017.  On 25 July 2017, the Cabinet approved the 101 billion baht budget and tender for the extension. However, the tender has been delayed until 2018. If construction commences in the second half of 2018, the extension will open in 2024.
North: A 4.5 km extension from Bang Yai to Bang Bua Thong intersection, which was not part of the original Purple Line plan, has previously been requested by the Nonthaburi governor.
- Mass Rapid Transit Master Plan in Bangkok Metropolitan Region
- BTS Skytrain
- Sukhumvit Line
- Silom Line
- Airport Rail Link (Bangkok)
- Bangkok Metro
- MRT Blue Line
- MRT Brown Line
- MRT Grey Line
- MRT Light Blue Line
- MRT Orange Line
- MRT Pink Line
- MRT Yellow Line
- SRT Red Lines
- Bangkok BRT
- Mahitthirook, Amornrat (26 November 2012). "Mall links to boost MRT's bottom line". Bangkok. Retrieved 26 November 2012.
- "Fare cut boosts Purple Line riders, but still below target - Bangkok Post Property finance advice". Bangkok Post. Retrieved 11 September 2016.
- "Purple Line use up 47% since 'missing link' completed". Bangkok Post. Bangkok. 8 September 2017.
- 'Purple Line deal agreed BEM signs 30-year contract with MRTA'. Bangkok Post, 5 September 2013
- "ITD closer to Purple Line contract". The Nation. Bangkok. 17 May 2012. Retrieved 26 November 2012.
- "Bangkok Purple Line contract awarded". International Railway Gazette. 22 October 2012. Retrieved 6 May 2013.
- "Archived copy". Archived from the original on 9 October 2014. Retrieved 2014-10-09.
- 'Japanese firms win Purple Line deal'. Bangkok Post, 6 November 2013
- "First Sustina export order". International Railway Gazette. 23 September 2014.
- http://www.bangkokpost.com/archive/b358bn-rail-projects-expected-to-go-ahead/1256406. Bangkok Post, 26 May 2017
- https://www.bangkokpost.com/archive/purple-line-south-link-bid-faces-delay/1357647. Bangkok Post, 10 Nov 2017
- Bid to extend Purple Line to Sai Noi intersection. The Nation, 5 May 2011
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