Skytrain approaching Nana Station
|Type||Medium-capacity rail transport system|
|Termini||Mo Chit Station
|Daily ridership||600,000 (2012)|
|Opened||December 5, 1999|
|Owner||Bangkok Metropolitan Administration (BMA)|
|Operator(s)||Bangkok Mass Transit System
Public Company Limited
|Rolling stock||Siemens Modular Metro|
|Line length||22.25 km (13.83 mi)
(32 km under-construction)
|Track gauge||1,435 mm (4 ft 8 1⁄2 in) standard gauge|
|Electrification||750V DC Third rail|
|Operating speed||80 km/h (49.71 mph)|
The Elevated Train in Commemoration of HM the King's 6th Cycle Birthday First Line (Sukhumvit) or Sukhumvit Line (Thai: รถไฟฟ้าบีทีเอส สายสุขุมวิท), a route of the BTS Skytrain in Bangkok, Thailand. From the central Siam Station, where it connects with the Silom Line, the elevated rail line runs northwards along Phaya Thai and Phahon Yothin Roads to Mo Chit Station (N8) in Chatuchak District, and eastwards along Rama I, Phloen Chit and Sukhumvit Roads to Bearing Station (E14) in Bang Na District.
The line originally consisted of seventeen stations (from Mo Chit to On Nut) when the BTS first opened in December 1999. A planned station at N6 has never been built.
The line is represented on the official BTS map in light green.
|N7||Saphan Khwai||สะพานควาย||Phaya Thai|
|E10||Bang Chak||บางจาก||Phra Khanong|
|E12||Udom Suk||อุดมสุข||(proposed)||Bang Na|
Extensions and current construction
1st extension - Construction started in August 2006 on a four billion baht, 5.25 km extension from On Nut (E9) to Bearing. The extension was funded by the BMA. The original scheduled opening date was mid-2009. However, an unusual delay in tendering of the contract for the electrical and signals resulted in a two year delay. "The senior City Hall official responsible for making the purchase has apparently stalled the scheme over fears of being investigated if something went wrong with the purchase, he said. The official in question is due to retire and does not want to take risks despite being told the scheme is strictly in line with regulations, said Mr Teerachon".
The BTSC was contracted by the BMA to run the extension. Subsequently, the extension did not open until over two years later on 12 August 2011. The delay in opening prompted the BMA to offer free travel for this extension until the end of 2011 as compensation. A flat fare is charged for this section. The fee for this extension is separate from the distance-based fare of the rest of the BTS network.
2nd extension, currently under construction - Construction started in April 2012 on a 12.6 km, seven station extension from Bearing Station to Samut Prakhan Station. Two stations (E18 and E22) will be built at a later date. The extension is funded by the MRTA as it is outside BMA city limits, Bangkok Province. Construction is contracted to take 1,350 days and the extension is planned to open in 2017. In April 2013, the MRTA awarded Ch Karnchang the contract for track laying and electrical systems. As of June 2014, civil works were stated to be 28.3 percent complete.
|E15||Samrong||สำโรง||(2019)||Samut Prakan||Mueang Samut Prakan|
|E16||Pu Chao Saming Phrai||ปู่เจ้าสมิงพราย|
|E19||Samut Prakan City Hall||ศาลากลางจังหวัดสมุทรปราการ|
|E23||Kheha Samut Prakan||เคหะสมุทรปราการ|
- 1) Mo Chit station to Saphan Mai: 11.4 km, 12 stations (N9–N20). (Contract signed)
- 2) Saphan Mai to Khu Khot: 7.5 km, four stations (N21-N24). (Contract signed))
- 3) Khu Khot to Outer Eastern Ring (Lam Lukka rd): nine km, four stations (N25-N29). (Planned)
A 11.4 km, 11 station northern extension from Mo Chit Station to Saphan Mai in Don Mueang District has been planned since the Sukhumvit Line opened. Originally, this extension was scheduled to be completed by 2008. However, due to a combination of changes in government, a prolonged EIA study, and problems with locating a suitable train depot the extension has been continually delayed.
A further 16.5 km, nine station extension from Saphan Mai to Lam Lukka was also planned once the extension to Saphan Mai had been completed. This was subsequently split into two extensions. A 7.5 km, four stations extension to Khu Khot and a nine km, four station extension along Lam Lukka Rd to the Outer Eastern Ring Rd.
Due to the significant delay in the northern extension plans, in mid-2013 it was decided to tender extension (1) and (2) at the same time by the end of 2013. However, the dissolution of parliament in November 2013 delayed this yet again. A tender was finally released in January 2014  with an April deadline before being delayed until late May 2014 due to concerns from bidders.
A military coup in late-May 2014 suspended the bidding process whilst the military administration reviewed all major projects. In late June, the military administration affirmed the tender which will proceed before the end of 2014. In mid-August, the MRTA announced that the new tender deadline will be 30 September 2014. Five bidders have qualified and successful bids will be announced by December 2014. It is envisaged that construction will commence by early-2015. The tender specifies a construction period of 1,350 days.
On 3 April 2015, MRTA signed four contracts for this extension, the construction are expect to start in June, 2015.
- Contract 1: Civil works of 11.4 km from Mo Chit to Saphan Mai, will be constructed by Italian-Thai Development (15,269 million baht)
- Contract 2: Civil works of 7.5 km from Saphan Mai to Khu Khot, will be constructed by UN-SH-CH joint venture (6,657 million baht)
- Contract 3: Civil works of Depot and Park and Ride building, will be constructed by STEC-AS joint venture (4,019 million baht)
- Contract 4: Track laying and system design, will be constructed by STEC-AS joint venture (2,841 million baht)
MRTA, contactors (1,2) and Thai Metro Police met on 2 September 2015. They decided to begin construction on 8 September 2015 and Kasetsart Bridge will be demolished on 12 September 2015, which will take 60 days to complete. 
|N24||Khu Khot||คูคต||Pathum Thani||Lam Luk Ka|
|N23||km 25||กม. 25||Bangkok||Don Mueang|
|N22||Royal Air Force Museum||พิพิธภัณฑ์กองทัพอากาศ||Sai Mai|
|N20||Saphan Mai||สะพานใหม่||Bang Khen|
|N18||Wongwian Lak Si||วงเวียนหลักสี่|
|N17||Wat Phra Sri Maha That||วัดพระศรีมหาธาตุ||(2019)|
|N16||11th Infantry Regiment||กรมทหารราบที่ 11|
|N14||Krom Pa Mai||กรมป่าไม้|
|N10||Phaholyothin 24||พหลโยธิน 24|
|N9||Lat Phrao Intersection||ห้าแยกลาดพร้าว|
Future extension plans
- A further 7 km, four station extension from Kheha Samut Prakan Station to Bang Pu Station is planned. It may be tendered by 2015-2016 for completion by 2019-2020.
- A further 9 km, four station extension east along Lam Lukka Rd from Khu Khot Station to Eastern Outer Ring Station is planned to be constructed by 2029.
|N28||Eastern Outer Ring||วงแหวนรอบนอกตะวันออก||Pathum Thani||Lam Luk Ka|
- Airport Rail Link (Bangkok)
- BTS Skytrain
- MRT Blue Line
- Bangkok Metro
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- Bangkok BRT
- Lists of rapid transit systems
- Groundbreaking starts on new BTS extension, Daily News, 15 August 2006
- BTS extension budget cut, Bangkok Post, 15 December 2006
- Skytrain link tests delayed, Bangkok Post, 19 September 2009
- "Ch Karnchang gets Phase 2 of Bearing-Samut Prakan route" The Nation, 13 April 2013
- http://www.prachachat.net/news_detail.php?newsid=1401076541 "รฟม.ปรับทีโออาร์หมอชิต-คูคต กลางปี59 เปิดให้บริการสายสีม่วง" Prachachat News, 26 May 2014
- "MRTA Greenline website"
- "2Bangkok BTS Light Green Line - Bearing to Paknam - south extension, construction thread" Semi-regular updates, articles, pictures and commentary (In English)
- "2Bangkok BTS Light Green Line - Mo Chit to Khoo Khot - north extension thread" Semi-regular updates, articles, pictures and commentary (In English)
- Airport Rail Link, BTS, MRT & BRT network map