Sukhumvit Line

The Elevated Train in Commemoration of HM the King's 6th Cycle Birthday 1st line, also known as Sukhumvit Line, is one of the rapid transit lines of the BTS Skytrain System in Bangkok, Thailand.^[4] The line runs from Siam Station, where it interchanges with the Silom Line, and continues both northwards along Phaya Thai and Phahon Yothin Roads to Khu Khot in Lam Luk Ka District, Pathum Thani, and eastwards along Rama I, Phloen Chit and Sukhumvit Roads, through Bang Na District to Kheha Station in Samut Prakan.

BTS Sukhumvit Line สายสุขุมวิท
EMU-A2 from Kasetsart University station arriving at Sena Nikom station
Overview
Owner	Bangkok Metropolitan Administration
Locale	Bangkok, Samut Prakan, and Pathum Thani
Termini	Khu Khot Kheha
Stations	Total : 57 stations 47 (operational) 9 (planned) 1 (provisional)
Color on map	Light Green
Service
Type	Rapid transit
System	BTS Skytrain
Operator(s)	Bangkok Mass Transit System Public Company Limited
Depot(s)	Mo Chit Depot (shared with  BTS ) Khu Khot Depot (shared with  BTS ) Kheha Depot
Rolling stock	Siemens Modular Metro EMU-A1: 35 four-car trains Siemens Bozankaya EMU-A2: 22 four-car trains CNR Changchun Railway Vehicles EMU-B1: 12 four-car trains CNR Changchun Railway Vehicles EMU-B2: 5 four-car trains CRRC Changchun Railway Vehicles EMU-B3: 24 four-car trains
Daily ridership	926,294 ( BTS  and  BTS ) 30 August 2024[1]
History
Opened	5 December 1999; 24 years ago
Last extension	16 December 2020; 3 years ago
Technical
Line length	Total :69.07 km (42.92 mi) 51.17 km (31.80 mi) (operational) 17.9 km (11.1 mi) (planned)
Character	Fully elevated
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	Former: Siemens Trainguard LZB700M fixed block ATC under ATO GoA 2 (STO) Current: Bombardier CITYFLO 450 moving block CBTC ATC under ATO GoA 2 (STO), with subsystems of ATP, ATS and CBI[2][3]
Route map Legend Planned extension to Outer Ring Road-Lam Luk Ka Khu Khot Khu Khot depot Yaek Kor Por Aor Royal Thai Air Force Museum Bhumibol Adulyadej Hospital Saphan Mai Sai Yud Phahon Yothin 59 Pink Line Wat Phra Sri Mahathat  MRT  11th Infantry Regiment Bang Bua Royal Forest Department Kasetsart University Sena Nikhom Ratchayothin Phahon Yothin 24 Ha Yaek Lat Phrao  MRT  Blue Line to Lak Song Don Mueang Tollway Mo Chit depot Mo Chit  MRT  Saphan Khwai Sena Ruam (future) Ari Sanam Pao Si Rat Expressway Victory Monument Phaya Thai  ARL  Airport Rail Link to Suvarnabhumi SRT Eastern Line to Bangkok │ to Chachoengsao Ratchathewi Silom Line to National Stadium Siam  BTS  Silom Line to Bang Wa Chit Lom Phloen Chit Chaloem Maha Nakhon Expressway Nana Asok Blue Line to Tha Phra (via Bang Sue) Phrom Phong Thong Lo Ekkamai Phra Khanong Chalong Rat Expressway On Nut Bang Chak Punnawithi Udom Suk Chaloem Maha Nakhon Expressway Third stage Expressway System Bang Na Bearing Samrong  MRT  Pu Chao Kanchanapisek Expressway Chang Erawan Royal Thai Naval Academy Pak Nam Srinagarindra Phraek Sa Sai Luat Kheha Samut Prakan depot Planned extension to Bang Pu This diagram: view talk edit

The line was first opened on 5 December 1999, along with the Silom Line. Both lines are operated by the Bangkok Mass Transit System Public Company Limited under a 30-year concession from the Bangkok Metropolitan Administration. When it opened, the line ran from Mo Chit to On Nut covering a total distance of 16.7 km (10.4 mi) with 17 stations. Currently, Sukhumvit Line is one of the main arteries of the Bangkok Mass Rapid Transit System with 900,000 daily passengers per day (combined with the Silom Line). The line rapidly expanded from 2011 until 2021, tripling its distance through three extension projects and reaching a total length of 51.17 km (31.80 mi) with 47 stations.

The Sukhumvit Line's initial proposal was for 12.8 km (8.0 mi) route running from   station to   station with the depot located at Lumphini Park near the Silom Line. However, this location for the depot faced backlash from the public opinion, which argued that it violated King Rama VI's intention in donating his land to establish Lumphini Park for the public. Additionally, there were protests demanding that the construction of both Skytrain lines be built underground instead of being fully elevated. Therefore, several alternative locations for the depot were considered, such as a vacant land plot in Soi Rangnam owned by the Crowned Property Bureau or the Phra Khanong pumping station in Sukhumvit 50. Ultimately, the Bangkok Metropolitan Administration decided to relocate the depot to the former site of the Northern Bus Terminal (commonly known as the Mo Chit Bus Terminal). With the decision made, the Sukhumvit Line route was extended from   station to   station. Several changes were made during the construction, as follows:^[5]

•  ,  ,  , and   stations were changed from an island platform to side platforms.

• The fully operational year was pushed from the end of 1996 to the end of 1999.

• Station designs were drastically changed from the EIA reports.

•   station was moved from the east side of Chaloem Phao junction to the west side.

•   station was moved from the east side of the Chit Lom junction to the west side, in front of Mater Dei School, with the two entrances in front of the school being canceled due to protests from school staffs and students concerned about privacy, landscape, and air pollution issues.

•   station was originally located between Sukhumvit 2 and Soi Nana but was later moved to the west side of the Chaloem Maha Nakhon Expressway.

•   station was moved from the east side of the Asok junction to the west side.

Construction started in August 2006 on a four-billion baht, 5.25 km (3.26 mi) extension from   On Nut to   Bearing which included 5 new stations^[6] The extension was funded by the BMA.^[7] The original scheduled opening date was mid-2009. However, a delay in tendering the contract for the electrical and signaling works resulted in a two-year delay.

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 on this extension until the end of 2011 as compensation.

Construction started in April 2012 on a 12.6 km (7.8 mi), nine station extension from   Bearing station to   Kheha station. The extension was funded by the MRTA as it is outside BMA city limits, Bangkok Province. Construction was contracted to take 1,350 days and the extension was originally scheduled to open by early 2017. In April 2013, the MRTA awarded Ch Karnchang the contract for track laying and electrical systems.^[8]

In June 2014, civil works were stated to be 28.3 percent complete. In August 2016, the BMA agreed to take over the operation of the extension from MRTA. Delays over the agreement of how much the BMA should pay MRTA caused a delay in the commencement of test runs on the extension. Track works were 98% completed by November 2016. The total cost of the extension was estimated at 21.4 billion baht.^[9] In January 2017, it was announced that the opening of the extension could be further delayed to 2018-2019 due to budgetary concerns and ongoing disputes between the MRTA and BMA.^[10]

The first 1.2 km (0.75 mi) section of the extension to   Samrong station opened on 3 April 2017.^[11] The full extension to   Kheha opened on 6 December 2018.^[12]

An 11.4 km, 11 station northern extension from   Mo Chit station to Saphan Mai in Don Mueang District had 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 environmental study, and problems with locating a suitable train depot the extension was continually delayed. A further 16.5 km (10.3 mi), nine station extension from Saphan Mai to Khu Khot was also planned once the extension to Saphan Mai had been completed.

After multiple delays, in mid-2013 a decision was made to tender extensions (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^[13] with an April deadline before being delayed until late May 2014 due to concerns from bidders.^[14] 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 that the tender would proceed before the end of 2014. In August 2014, the MRTA announced that the new tender deadline was 30 September 2014.^[15] Five bidders qualified and the successful bids were announced in December 2014.^[16] The tender specified a construction period of 1,350 days.

On 3 April 2015, MRTA signed four contracts for this extension:^[17]

The MRTA, contactors and Thai Traffic Police met on 2 September 2015 and confirmed construction would begin on 8 September 2015. A flyover at Kasetsart was demolished, which commenced on 12 September 2015.^[18]

At 31 December 2017, the progress of civil works construction was at 53.31% according to the MRTA.^[19] As of the end of April 2018, the MRTA stated that civil works progress had advanced to 63.27%.^[20] As of 30 September, overall construction had progressed to 78.79%.^[21] By the end of March 2019, civil construction had nearly been completed having progressed to 99.42%.^[22]

Testing of the final 9.8 km, 7 station section from Wat Phra Sri Mahathat (N17) to Khu Khot (N24) began on 5 October.^[23] The final section was officially opened on 16 December 2020 by the Prime Minister.^[24]

There is a plan to extend Sukhumvit Line from   Kheha to   Tamru for 10.1 km (6.3 mi), including 5 additional stations:   Sawangkhaniwat,   Mueang Boran,   Si Chan Pradit,   Bang Pu, and   Tamru. Currently, this extension has been suspended indefinitely until clarity is reached regarding passenger guarantees.

There is a plan to extend Sukhumvit Line from   Khu Khot Station eastwards for 7.8 km (4.8 mi), including 4 additional stations:   Khlong Sam,   Khlong Si,   Khlong Ha, and   Eastern Ring Road-Lam Luk Ka. Currently, this extension has been suspended indefinitely until clarity is reached regarding passenger guarantees.

  Sena Ruam station has been planned since the construction of the line but has not been built.

BTS operates services throughout the line from Khu Khot to Kheha at all times. At peak hours between 07.00-09.00 and 16.00-20.00, some "short-run" services run terminate at Mo Chit and Kasetsart University northbound, and at Samrong, eastbound. Trains run generally at three to six-minute intervals. The last eastbound trains from Khu Khot terminate at Kheha, Samrong or Ha Yaek Lat Phrao. The last northbound trains from Kheha terminate at Khu Khot, Mo Chit, or Samrong.

A few off-peak eastbound trains run a through service on the Silom Line to Bang Wa, in order to increase the line capacity at peak hours. At night, these trains will run back northbound and head to depot.^[31] Some late northbound trains on the Silom Line switch to the Sukhumvit Line at Siam to reach the depot at Mo Chit.

• Mass Rapid Transit Master Plan in Bangkok Metropolitan Region
• BTS Skytrain
• Silom Line
• MRT (Bangkok)
• MRT Brown Line
• MRT Blue Line
• MRT Grey Line
• MRT Light Blue Line
• MRT Orange Line
• MRT Pink Line
• MRT Purple Line
• MRT Yellow Line
• AERA1 City
• SRT Dark Red Line
• SRT Light Red Line
• BMA Gold Line
• Bangkok BRT