BTS Skytrain

On 18 October 2005, with no approval from the central government forthcoming, Bangkok Metropolitan Administration (BMA) decided to fund and complete the 2.2 kilometers (1.4 mi) Silom Line route extension to Krung Thonburi Station (S07) and Wongwian Yai Station (S08). Construction began on 13 December 2005 with completion originally expected within two years. However, problems with the tendering and installation of a new Bombardier open signalling system repeatedly pushed back the schedule. The extension finally opening on 15 May 2009. However, the single platform Saphan Taksin station which has only one track, has caused repeated delays during rush hour. In 2012, the BMA announced plans to demolish Saphan Taksin station in the future. There are now plans to construct new platforms and remove the bottleneck and keep the station which provides an important link between river boats. The plan includes redesigning the road bridges either side of the viaduct to fit the new station.

A second extension, the 5.25 km On Nut station (E09) to Bearing station (E14) started construction in August 2006.[22] The 4 billion baht extension was again funded by the BMA.[23] The original scheduled opening date was mid-2009. However, an unusual, prolonged delay in the 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."[24]

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 separate from the distance based fare normal in the BTS network was then charged for this section. However, distance based fares are now used for this extension.

The third extension to the network, a 5.3 km, four station extension from Wongwian Yai (S8) to Bang Wa (S12) in Phasi Charoen District began construction in the 2nd quarter of 2011 with a deadline of the end of 2012. Only the stations had to be constructed as the viaduct had been completed some years prior. However, construction was delayed for many months by the Bangkok floods of late 2011. It eventually opened in stages. Pho Nimit opened on 12 January 2013, Talat Phlu opened on 14 February 2013, with the last two stations opening on 5 December 2013.[25] For most of 2013, passengers changed platforms and trains at Wongwian Yai for a shuttle service to S09 and S10 as there was no turnout at S10 for through trains. Since the opening of the final section of the extension to Bang Wa station on 5 December 2013, this is no longer the case.

Construction started in April 2012 for a 12.6 km (7.8 mi), seven station extension from Bearing station (E14) to Samut Prakan Station (E23). The extension is being built by Ch. Karnchang.[26] Two stations (E18 & E22) will be built at a later date. The extension was funded by the MRTA as it is outside BMA city limits. The extension was planned to open in 2017. In April 2013, the MRTA awarded Ch Karnchang the contract for track laying and electrical systems.[27] Construction was completed in 2017, but arguments over who should operate the line delayed the opening. One station, Samrong opened earlier, on 3 April 2017. The full extension opened on 6 December 2018 and the BTSC has announced that the free travel concession on this section will continue until the new train sets arrive to allow for the new section to be fully functional.

• 1) Mo Chit station to Saphan Mai: 11.4 km, 12 stations (N9–N20).
• 2) Saphan Mai to Khu Khot: 7.5 km, four stations (N21-N24).

An 11.4 km, 12 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 environmental 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 station extension to Khu Khot and a 9 km, five station extension along Lam Lukka Road to Lam Lukka.

Due to the significant delay in the northern extension plans, in mid-2013 it was decided by the MRTA to tender extensions (1) & (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[28] with an April deadline before being delayed until late May 2014 due to concerns from bidders.[29]

A military coup in late-May suspended the bidding process while 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 would be 30 September 2014.[30] Five bidders qualified with successful bids to be announced by December.[31] The contract to construct the line for both extensions (1) & (2) was finally signed in April 2015 and the full extension is scheduled to open in 2020.[32][33]

Testing of the final 9.8 km, 7 station section from Wat Phra Sri Mahathat (N17) to Khu Khot (N24) began on 5 October and continued until the full extension opens.[34] It was officially inaugurated on 16 December 2020 by the Prime Minister.[35]

Opening dates

1. The first section to Ha Yaek Lat Phrao station (N9) opened on 9 August 2019;
2. the next 4 stations from Ha Yaek Lat Phrao station (N9) to Kasetsart University (N13) opened on 4 December 2019;
3. further 4 stations from Kasetsart University (N13) to Wat Phra Sri Mahathat (N17) opened on 5 June 2020;
4. the remaining section of 9.8 km and 7 stations from Wat Phra Sri Mahathat (N17) to Khu Khot (N24) opened on 16 December 2020.

In 2018, it was decided to finally build the missing Saint Louis (S4) station (originally named Sueksa Wittaya), the EIA was finalised in March 2019.[36] Construction of the station began in August 2019 and by the end of 2019 had reached 25% progress.[37] By August 2020, construction had reached 50% but was 30% behind schedule due to COVID related delays.[38]

The station is expected to open in February 2021.[39]

A further 9 km, five station extension from Khu Khot station to Wongwaen-Lam Luk Ka station is planned to be constructed by 2029.

• A further 7 km, five-station extension from Kheha station to Bang Pu station is planned to be constructed by 2029.
• A spur line from Bang Na to Suvarnabhumi Airport (terminating at future South Passenger Terminal of Suvarnabhumi Airport). However, this may also be built as a light rail (monorail) line.

After the opening of Wutthakat (S11) and Bang Wa (S12) stations 5 December 2013, the BMA announced a new proposal to further extended the Silom line by 7 km from Bang Wa (S12) station, by six stations to Taling Chan.[41] At Taling Chan it would connect with the SRT Light Red line.

A public hearing was held in 2015.[42] Three route options were considered, with construction intended to start in 2017.[43] Part of the basis for this further extension by the BMA is that it would provide proximate access to the Southern Bus Terminal. The BMA Transport and Traffic Office completed an economic evaluation of the extension in October 2018 which found a cost benefit ratio of 2.37.[44] The study recommended that an EIA be completed in 2019 but this was delayed.

The Silom Line is planned to be extended by one or two stations west along Rama 1 from National Stadium (W1) to link with the SRT Dark Red Line at Yot Se station. However, no time frame for this extension has been announced and this section of the SRT Dark Red Line will not be built until after 2022.

Originally, the plan was to extend the Silom Line west from National Stadium into Chinatown, then north to Democracy Monument where it would then run west to Rattanakosin Island and Sanum Luang, tunnel under the river to the Thonburi side before terminating at Phran Nok. However, this plan was shelved in 2009 and much of this route has been replaced by routing changes to the planned MRT Orange Line.

Siemens Modular Metro train (EMU-A1)

The rolling stock of BTS Skytrain, in use when the line opened in 1999, consisted of 35 Siemens Modular Metro trains from Siemens. These initial trains had three cars, two motor cars and one trailer in the center. The Sukhumvit Line used 20 trains, and the Silom Line had 15.

After the 12 new car CNR trains were delivered for the Silom line in December 2010, the 15 Siemens trains on the Silom Line were transferred to the Sukhumvit Line.

To increase capacity, in October 2010, BTSC ordered an extra 35 single cars from Siemens to make each train a four car set.[45][46]

These extra cars were progressively introduced into operation from November 2012 to March 2013, when all 35 sets of Siemens rolling stock finally became four car sets.[47]

The Silom Line cars have been modified to support a signaling system from Bombardier Transportation since the extension from Saphan Taksin to Wong Wian Yai.

To serve the Sukhumvit Line Extension (East) BTSC ordered 22 new Siemens Inspiro four-car trains from a consortium of Siemens and Bozankaya in May 2016.[48]

These trains were manufactured in the Bozankaya factory in Ankara, Turkey. Siemens supplied bogies, traction, braking and auxiliary systems and was responsible for project management, development, construction and commissioning of the trains. Siemens will also take on service and maintenance for 16 years.

The first set of the new batch of rolling stock arrived in early August 2018 for testing and approval by the BTSC. These new trains increase capacity from 1,490 passengers per train to 1,573.[49][50] As of the opening of the new Sukhumvit Line extension to Kheha Samut Prakan on 6 December 2018, only 3 sets of the 22 sets had been delivered. This resulted in a limited 10-minute frequency, shuttle service for the new extension as an interim measure until more rolling stock is delivered.

The train features : Perch Seats, LCD Dynamic Route Map (AKA. Passengers Information Display)

Changchun Railway Vehicles train (EMU-B1,EMU-B2)

In early 2008, the BTSC ordered 12 new trains (12 sets of four cars) from Changchun Railway Vehicles (EMU B class) to cater for the then soon to open Wong Wian Yai extension of the Silom Line. Their design was modified to the existing BTS's Siemens Modular Metro. The new trains were delivered late and only began service the Silom Line in December 2010. This was some 18 months after the Wong Wian Yai and Krung Thonburi stations were opened in May 2009 during which time there was severe overcrowding on the Silom line.

These trains consist of two-motor cars and two-trailer cars (i.e., four-car trainsets) and feature LCD TVs for public announcements and advertising. An advanced digital voice announcement (DVA) and passenger information systems was installed.

In September 2011, the BTSC ordered five more four-car trainsets of CNR rolling stock for 1.5 billion baht to prepare for the Silom Line extension to Bang Wa which was then due to open in December 2012.[51] These five new train sets of rolling stock entered service on 29 November 2013 after the first two stations of the Silom Line extension to Bang Wa opened in January and February 2013, respectively. This second batch of CNR EMUs (B Class) differ slightly from the first batch in exterior fitting out such as with the LCDs screens, LED route displays, signage, and passenger communication units.

CRRC Changchun Trains

Changchun Railway Vehicles train (EMU-B3)

In May 2016, BTSC has signed a contract to order 24 more four-car trains of CRRC Changchun Railway Vehicles rolling stock to prepare for the Sukhumvit Line extension (North) and to cater for increasing demand, with expected delivery in 2018.[48]

It has delivered 24 of its cars to Mo Chit Depot. 24 cars are now operating its service on the Silom Line and Sukhumvit Line (Car 75–98)

This train features : Perch Seats, LCD Dynamic Route Map (AKA. Passengers Information Display)