Circle MRT line

This article is about the rapid transit system in Singapore. For the rapid transit system in Malaysia, see MRT Circle Line.

Circle Line
Bishan MRT station, one of the most crowded stations on the Circle line.
Overview
Native name	Laluan MRT Bulatan 地铁环线 இணைப்பு எம்ஆர்டி வழி
Status	Operational Under construction (Stage 6)
Owner	Land Transport Authority
Termini	Dhoby Ghaut Stadium (All trains departing from Marina Bay will end here during off-peak hours) HarbourFront Marina Bay
Stations	30 (Operational) 3 (Under construction)
Service
Type	Rapid transit
System	Mass Rapid Transit (Singapore)
Services	3
Operator(s)	SMRT Trains (SMRT Corporation)
Depot(s)	Kim Chuan
Rolling stock	C830 C830C C851E (Future)
Daily ridership	398,000 (May 2015)
History
Planned opening	2025 (2025) (Stage 6)
Opened	28 May 2009 (2009-05-28) (Stage 3) 17 April 2010 (2010-04-17) (Stages 1 and 2) 8 October 2011 (2011-10-08) (Stages 4 and 5) 14 January 2012 (2012-01-14) (Circle line extension)
Technical
Line length	35.5 km (22.1 mi) (Operational) 4 km (2.5 mi) (Under construction)
Character	Fully Underground
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge
Electrification	750 V DC third rail
Operating speed	limit of 78 km/h (48 mph)
Route map

The Circle Line (CCL) is a medium-capacity Mass Rapid Transit line in Singapore. It runs from Dhoby Ghaut and Marina Bay in the Central Area to HarbourFront in the south, with the line between Marina Bay and Stadium operated as a shuttle service during off-peak hours. The line is 35.5 kilometres (22.1 mi) long with 30 stations, all of which are underground. Travelling from one end of the line to the other takes about one hour. It is coloured yellow-orange on the rail map.

It is the second in Singapore to be completely automated and driverless and is among the world's longest driverless rapid transit lines. Its station code texts are coloured in black due to initial visibility issues. The line is the fourth MRT line to be opened, with the first section having opened on 28 May 2009.

The Circle Line is the first medium capacity line in Singapore. Each Circle Line train has a three-car configuration. As of May 2015, the daily ridership is 398,000. The line reduces travelling time for commuters by shortening trips between northern, eastern and western Singapore, and bypassing busy interchange stations like City Hall and Raffles Place. It is the third MRT line to be operated by SMRT, after the North South Line and the East West Line.

Overview

As the name implies, the line is an orbital circle route linking all radial routes leading to the city. It also covers many parts of the Central Area. From Promenade, the line branches into two, with one branch terminating at Dhoby Ghaut, and the other at Marina Bay. The Circle Line interchanges with all other Mass Rapid Transit lines within Singapore, such as the North South Line and East West Line.

History

Plans for the Circle Line were laid out in the 1980s, when the then Minister for Communications and Information, Dr Yeo Ning Hong stated that such a system "would be feasible when the population reaches four million."

File:Singapore MRT Circle Line close-up (3535720104).jpg

The first five stations opened on the Circle line

The Circle Line was first named as the Marina line in May 1998, initially planned as a 12-station underground line, starting from Chinatown and Dhoby Ghaut via the National Stadium to either Kallang or Paya Lebar station. However, the Chinatown leg was later truncated and was reduced to 6 stations up to Stadium station. On the other hand, a further extension towards Upper Paya Lebar was added in the year 2000. The Marina line was also merged with an LRT line that goes from Paya Lebar to Buona Vista via Serangoon and Bishan to form Circle Line Stage 3 and 4 in 2001. Circle Line Stage 5 was finalised in February 2002 when Stage 4 was extended from Buona Vista to World Trade Centre to close up the link and to provide connectivity from the west to Sentosa, and it became the full Circle Line in the end. Stations in Circle Line that were a part of the original Marina line plans include Dhoby Ghaut, Bras Basah, Esplanade, Promenade, Nicoll Highway and Stadium. The part of the previously planned Marina line from Chinatown to Promenade is now part of the Downtown Line.

Construction started on 13 March 2002 for Stage 1, 5 September 2002 for Stage 2, May 2003 for Stage 3, and January 2005 for Stages 4 and 5, and the Circle Line was supposed to be opened in stages from 2006 to 2010, with an estimated cost of S$6.7 billion, but the Nicoll Highway collapse caused the opening of the first stage to be delayed to 28 May 2009. When the line fully opened on 8 October 2011, the cost of construction had escalated to nearly S$10 billion. Due to the re-alignment of the Nicoll Highway station to a new location, the station is only two-thirds the size of the original plan before the collapse. It was located 100 metres (330 ft) away from the original site. Some stations on the Circle line were initially designed as 'shell stations', but the decision was made to open Caldecott and Haw Par Villa (previously Thomson and West Coast respectively), which leaves Bukit Brown as the only unopened station on the line.

View of underground platform at Bishan station of the Circle line from ground level during construction in 2007

Bukit Brown station, the only "shell station"

Stage 3, a 5 kilometres (3.1 mi) five-station segment stretching from Bartley to Marymount, was the first section of the line opened, on May 28, 2009. Initial ridership on this section was lower than estimated, at 32,000 passengers per day (ppd) instead of the estimated 55,000 ppd. Tunneling works for the entire line were completed on August 17, 2009. Stages 1 and 2 started operations on April 17, 2010, Stages 4 and 5 on October 8, 2011, and the final Circle line Extension on January 14, 2012. The line was also fully completed in October 2011 to commemorate SMRT's 24th anniversary.

Circle Line Stage 6

On 17 January 2013, the Land Transport Authority (LTA) announced 'Circle Line stage 6' which will finally 'close the circle'. This 4 km extension runs between Marina Bay and HarbourFront. This extension will connect commuters between HarbourFront to Marina Bay stations, and expand the rail network to the southern edge of the Central Business District. On 29 October 2015, LTA announced the station locations for stage 6. The working names of the stations are Keppel, Cantonment and Prince Edward. Tenders were called for construction between 2016 and 2017, and demolition, diversion and utility works commenced in 2017.

On 15 May 2017, Land Transport Authority (LTA) invited the public to send in suggestions for names of the three new MRT stations. Their current working names are derived from their proximity to names of nearby locations. The public can also propose to keep their current names, which are Keppel, Cantonment and Prince Edward. On 28 September 2018, the LTA finalised the names for Keppel and Cantonment, while Prince Edward was finalised as Prince Edward Road.

Construction of the Circle line stage 6 commenced in late 2017. A joint venture – by China State Construction Engineering (The Singapore branch) and Nishimatsu Construction – won the contract to build the new Keppel MRT station and its associated tunnels.

Incidents

Nicoll Highway collapse

Main article: Nicoll Highway collapse

On 20 April 2004, a section of the tunnel being built for the Circle Line collapsed, when a retaining wall used in the tunnel's construction gave way. This incident occurred near the proposed site of the Nicoll Highway station, not far from the Merdeka Bridge. The accident left a collapse zone that was 150 metres (490 ft) wide, 100 metres (330 ft) long, and 30 metres (98 ft) deep. Four workers were killed, three were injured.

A criminal inquiry found the main contractor Nishimatsu Construction Company and joint venture partner firm Lum Chang Construction Company and their officers, as well as key Land Transport Authority officers responsible for the collapse. Several other officers and subcontractors were reprimanded and issued warnings in connection with the accident.

As a result of this accident, the first phase of the Circle Line, previously scheduled to open in 2008, was completed in 2009 instead. The affected station has been shifted about 100 metres (330 ft) away from the accident site and is now located at Republic Avenue.

This accident had also resulted in stricter safety regulations for the construction of all future MRT lines. The shifting of the Nicoll Highway station also meant it can no longer serve as a terminus for the Bukit Timah Line, partially influencing the creation of the current Downtown line.

Other incidents

On 16 August 2007, the Building and Construction Authority (BCA) issued a stop-work order and revoked the contractor's tunnelling permit after a 7-metre (23 ft) stretch of two lanes sank about 20 centimetres (7.9 in), close to the junction of Telok Blangah Road and Alexandra Road in the evening, resulting in a halting of tunnelling works.

A section of the road above a construction site near Holland Road caved in on the morning of 24 May 2008, creating a massive hole. The hole, directly in front of two private houses along Cornwall Gardens, measured 8 by 7 metres and was 3 metres deep. No one was injured, but the road was temporarily closed to traffic.

Line disruptions

On 20 September 2011, a power fault disrupted train services on all 16 stations on the Circle Line. The four hours delay left thousands of commuters stranded during rush-hour. It was reported that leaks and a damaged electrical cable along the Circle Line were the cause of the disruption. The disruption started at about 5.30 am. Train services were gradually restored from 8 am and all services were restored just before 10 am. Dakota and Mountbatten stations were the last two to resume operations. Investigations were carried out. It was later found that a faulty cable beneath the platform level at Dakota station caused a power fault on Tuesday morning that affected train services at all 16 stations on the Circle Line. 27,000 passengers were affected by the disruption during the four hours delay, with bus bridging services plying the Circle Line route.

In late August 2016, intermittent signal interference led to a five-day series of train disruptions. The issue reappeared in November. A team of data scientists explored the data and discovered via a Marey Chart visualization that it was caused by hardware problems, sending errant signals from a "rogue" train, PV46.

Stations

Main article: List of Circle MRT line station names

Station Number	Station Name	Images	Interchange/Notes
CC1  NS24  NE6	Dhoby Ghaut		Interchange with the North South line and the North East line
CC2	Bras Basah
CC3	Esplanade
CC4  DT15	Promenade		Interchange with the Downtown line Change for train services towards Bayfront or Marina Bay stations
CC5	Nicoll Highway
CC6	Stadium		Marina Bay shuttle terminus during off-peak hours
CC7	Mountbatten
CC8	Dakota
CC9  EW8	Paya Lebar		Interchange with the East West line
CC10  DT26	MacPherson		Interchange with the Downtown line
CC11	Tai Seng
CC12	Bartley
CC13  NE12	Serangoon		Interchange with the North East line
CC14	Lorong Chuan
CC15  NS17	Bishan		Interchange with the North South line
CC16	Marymount
CC17  TE9	Caldecott		Interchange with the Thomson-East Coast line (2020)
CC18	Bukit Brown
CC19  DT9	Botanic Gardens		Interchange with the Downtown line
CC20	Farrer Road
CC21	Holland Village
CC22  EW21	Buona Vista		Interchange with the East West line
CC23	one-north
CC24	Kent Ridge
CC25	Haw Par Villa
CC26	Pasir Panjang
CC27	Labrador Park
CC28	Telok Blangah
CC29  NE1	HarbourFront		Interchange with the North East line
Stage 6 (under construction, to be ready by 2025)
CC30	Keppel
CC31	Cantonment
CC32	Prince Edward Road
Circle Line extension
CE1  DT16	Bayfront		Cross-platform interchange with the Downtown line
CE2  NS27  TE20	Marina Bay		Interchange with the North South line and the Thomson-East Coast line (2021)

The Circle Line's numbering scheme reserves station code "CC18" for future use.

Rolling stock

The rolling stock consists of 40 Alstom Metropolis C830 trains running in three-car formation. They are stabled at Kim Chuan depot, the world's largest underground depot when it opened in 2009. 24 new Alstom Metropolis & Shanghai Electric C830C trains were delivered to SMRT from end July 2014. They began operation on 26 June 2015. Currently, all 24 C830Cs are in revenue service.

The automated CBTC system on board relies on "continuous two-way digital communication" between each controlled train and the control centre.

To facilitate the extension of the line with the construction of Stage 6, a tender for additional trains for the line was published on 31 March 2017.

Train control

The Circle line is equipped with Alstom Urbalis 300 Communications-based train control (CBTC) moving block signalling system on the MASTRIA system with Automatic train control (ATC) under Automatic train operation (ATO) GoA 4 (UTO). The subsystems consist of Automatic train protection (ATP) to govern train speed, Iconis Automatic Train Supervision (ATS) to track and schedule trains and Smartlock Computer-based interlocking (CBI) system that prevents incorrect signal and track points to be set.

Train Data Management System (TDMS) which concentrate and dispatch the rolling stock information with fixed equipment. The IAGO Waveguide communications network has the capability to transmit video and is almost maintenance-free. Base stations are located within the signalling equipment room.

Automatic platform screen doors supplied by Westinghouse provide safety for commuters, offering protection from arriving and departing trains.

External links

• Media related to Mass Rapid Transit (Singapore) Circle Line at Wikimedia Commons
• Circle line