# Sengkang LRT line

The Sengkang LRT line (SKLRT) is a 10.7-kilometre (6.6 mi) elevated automated guideway transit line in Sengkang, Singapore. The driverless system consists of 14 stations on two loops, with Sengkang station connecting both loops and connecting the line to the North East MRT line. It is the second Light Rail Transit (LRT) line in Singapore, and the first LRT line operated by SBS Transit.
The SKLRT was planned in tandem with the development of the Sengkang estate. Construction of the LRT stations and viaducts was completed in 2001, and the LTA transferred operations to SBS Transit in September 2002. The east loop began operations on 18 January 2003, followed by the west loop on 29 January 2005, with Kupang station being the last to open on 27 June 2015.
The line operates using the Kyosan Automated People Mover (APM) fixed block signalling system and Mitsubishi Heavy Industries' Crystal Mover APM vehicles. Two-car operations were introduced in December 2015 to accommodate increased ridership. Between 2018 and 2022, the SKLRT underwent renewal works to improve reliability. A new fleet of 25 two-car APMs is expected to enter service in 2025, replacing 25 one-car trains and half of the 16 two-car trains in the existing fleet.

## History
### Planning and construction

At the groundbreaking ceremony of the Bukit Panjang LRT line on 27 September 1996, deputy prime minister Tony Tan announced the government's decision to proceed with the Sengkang LRT (SKLRT) project. The line would be developed alongside the Sengkang estate and integrated with future developments, intended to improve accessibility and convenience for residents. An exhibition for the SKLRT opened on 7 December 1996. The SKLRT was planned to be completed in 2002.
The contract for the design and construction of the Sengkang and Punggol LRT lines was awarded to a joint venture on 4 July 1998 for S$656 million (US$392 million). The joint venture comprised Singapore Technologies Industrial Corporation, Mitsubishi Heavy Industries and Mitsubishi Corporation. On 20 May 1999, SBS Transit (then Singapore Bus Service) was appointed to operate the SKLRT along with the North East line and the Punggol LRT line.
Construction of the LRT stations and viaducts was completed in 2001. In December that year, subcontractor BRR Holdings withdrew from the LRT project and handed over its responsibilities to SembCorp Engineers and Constructors. According to the Land Transport Authority (LTA), the withdrawal had minimal impact on the construction schedule.
On 1 September 2002, the LTA transferred operations of the SKLRT to SBS Transit, which conducted extensive test runs and trials on the line. This comes in light of frequent delays and breakdowns experienced on the Bukit Panjang LRT. In December 2002, transport minister Yeo Cheow Tong said the opening of the SKLRT would be delayed due to modifications required for the communication and radio systems.

### Stations opening

Sengkang LRT line stations timeline :
| Date | Project | Description |
| 18 January 2003 | East Loop | Opening of the East Loop |
| 29 January 2005 | West Loop | West Loop (except for Cheng Lim, Farmway and Kupang) opened in uni-directional manner. |
| 15 November 2007 | West Loop | Farmway opened for passenger service. |
| 4 January 2010 | West Loop | West Loop operated in both directions during the morning and evening peak hours on weekdays. |
| 1 January 2013 | West Loop | Bidirectional services on the West Loop commenced throughout the day and Cheng Lim was opened for passenger service. |
| 27 June 2015 | West Loop | Kupang opened for passenger service. |
The east loop commenced operations on 18 January 2003, offering free rides during its first two days. At the time, 90% of Sengkang residents lived along the east loop, while the west remained largely undeveloped. Although the east loop was scheduled to open at 2 pm that day, SBS Transit began operations 30 minutes earlier to accommodate the queue of the 100 waiting commuters. The initial fare on the Sengkang LRT was S$0.64 per trip (US$0.48). The system experienced its first breakdown on 5 September that year because of a computer failure. Free bus services were provided during the 30-minute disruption.
With the exception of the Farmway, Cheng Lim and Kupang stations, the west loop commenced operations on 29 January 2005. To mark the commencement of the west loop, Wee Siew Kim, Adviser to Jalan Kayu Grassroots Organisations, officiated the opening of the bridge linking Thanggam Station to Jalan Kayu via Lorong Samak. The west loop initially operated unidirectional services in the peak flow direction. Morning services from 5:20 am to 3:00 pm ran anti-clockwise from Thanggam to Renjong, while evening services from 3:00 pm to 12:35 am operated clockwise from Renjong to Thanggam.
Farmway station opened on 15 November 2007, to serve the Anchorvale Community Club and the Sengkang Sports Complex. On 4 January 2010, the west loop commenced bidirectional services only on weekday peak hours from 6:45 am to 9:00 am and from 6.15 pm to 8.30 pm. Full-day bidirectional services on the west loop began on 1 January 2013 with the opening of Cheng Lim station. Kupang station opened on 27 June 2015 to cater to new residential developments in its vicinity. Daily ridership on the SKLRT at the time had reached 60,000.
A power trip caused a two-hour disruption on the evening of 1 June 2016. On 16 February 2018, a dislodged power collector shoe caused a train to stall near Sengkang station. SBS Transit reported a "loud boom" was heard before the train stalled. Passengers disembarked from the faulty train before a rescue train hauled the train away. Services resumed at 1 pm. On 9 June 2024, the signalling system's power supply failed during upgrading works. As a result, no trains could be launched on that morning, with services only resuming at 10:12 am.

### Upgrades

On 31 October 2012, the LTA announced plans to increase passenger capacity of the Sengkang and Punggol LRT lines (SPLRT) to cater to increased ridership on the SPLRT. The upgrading works involved retrofitting 16 of the 41 one-car trains for two-car operations while purchasing 16 additional cars. Two-car operations on the SKLRT began on 22 December 2015. The official inauguration of two-car operations on the SKLRT was held on 5 January 2016, with Senior Minister of State for Transport Ng Chee Meng and other Sengkang Members of Parliament in attendance.
On 15 December 2017, the LTA announced plans to renew and upgrade the SPLRT to enhance its operational reliability. The works included replacing the power rail and its assemblies, along with conducting maintenance on the signalling switch machines and cables. Additionally, the crossheads supporting the viaducts were to be reinforced and the viaduct bearings replaced, following the discovery of cracks on the crossheads during routine inspections.
The maintenance works took place on selected Sunday mornings from 14 January to 25 February 2018. On these days, the affected loops ran unidirectional services from 5:30 am to 7:00 am. Unidirectional services remained in operation on Sunday mornings from 4 March to 29 April due to the extension of maintenance works on the SPLRT. These works involved replacing the power rail and power rail assemblies, as well as carrying out preventive maintenance on the signalling cables. Rectification works on the concrete plinths and elevated slabs were conducted on Sunday evenings between May 27 and October 7. These works involved breaking up the existing concrete plinths, realigning the finger joints, and recementing them into position. Maintenance works during service hours continued in 2020, 2021, and 2022.
In May 2018, the LTA announced plans to refurbish the Sengkang LRT platform. The upgrades included expanding the LRT platform and installing new dual-speed escalators and a new lift to connect the platforms, concourse and mezzanine levels of the station. The works were expected to be completed by 2022. New signs and queue markings were implemented to indicate new stopping locations for each of the four LRT routes plying the station. The refurbished LRT platforms began operations at the end of September 2024.
On 5 February 2021, the LTA announced plans to purchase 17 two-car trains for the SPLRT, which was expected to be delivered from 2024 to 2027. The 3.5 ha (8.6-acre) Sengkang Depot would also be expanded to 11.1 ha (27.4 acres) to ensure additional capacity and maintenance space for the new trains. The depot expansion also included the construction of two new reception tracks to reduce train launching time. In February 2022, the contract for the depot expansion was awarded to Sato Kogyo (S) Pte Ltd for S$157 million (US$117.2 million), and the contract for the new fleet of trains was awarded to Mitsubishi Corporation for S$439 million (US$327.6 million).

## Network and operations
### Route and service

The Sengkang LRT (SKLRT) is fully elevated automated guideway transit line, with a route length of 10.7 kilometres (6.6 miles). It is coloured grey on official maps. On dynamic passenger information displays and static signs on the platforms, yellow indicates the east loop, and red indicates the west loop. The SKLRT has four routes operating on two bi-directional loops that converge at Sengkang station. The line generally runs along road medians, with an average viaduct height of 15 metres (49 ft).
On the east loop, the line heads north from Sengkang station before curving eastward and running along the medians of Compassvale Street and Rivervale Drive. After passing Rumbia station, it turns south along Rivervale Drive, then west along Sengkang East Avenue, completing the loop by heading north back to Sengkang station. On the west loop, the line from Sengkang station diverge west toward Cheng Lim station. A spur connects the SKLRT to the Punggol LRT line across the Tampines Expressway, but there is at present, no LRT service between SKLRT and Punggol LRT lines. The SKLRT runs along Anchorvale Street and Fernvale Street. Between the Farmway and Kupang stations, the line crosses Sungei Punggol. After Kupang station, the line turns south along Fernvale Road, and turns east along Sengkang West Avenue. It crosses Sungei Punggol again between Layar and Tongkang stations, with reception tracks connecting the line to Sengkang Depot. Following Renjong station, the line completes the loop by heading north back to Sengkang station. From 30 September 2024, SKLRT at Sengkang station was upgraded with four boarding locations, dedicated for each bi-directional travel direction on both east and west lines.
The line operates between 5:18 am (5:38 am on Sundays and public holidays) and 12:37 am daily. The SKLRT is operated by SBS Transit. Since 2018, the SKLRT has been part of the New Rail Financing Framework (NRFF). Previously, the operator (the owner of the rail assets) had to bear the cost of maintaining and upgrading trains and signalling. Under the NRFF, the LTA and SBS Transit will share the profits and financial risks in operating the line and the LTA will take control of its operating assets on 1 April 2033. SBS Transit will operate the line under a 15-year licence which will expire on 31 March 2033.

### Stations

The east loop has five stations, while the west loop has eight stations. The average distance between stations are 300 metres (980 ft), with each station positioned to serve residents within a 400-metre (1,300 ft) radius.
| Station code | Station name | Opening | Further information | Location(s) |
| STC NE16 | Sengkang | 18 January 2003; 22 years ago | Interchange with the North East Line . Close to the Sengkang Bus Interchange. | 1°23′30″N 103°53′42″E﻿ / ﻿1.391653°N 103.895133°E﻿ / 1.391653; 103.895133 |
| East Loop ||||||
| SE1 | Compassvale | 18 January 2003; 22 years ago | — | 1°23′40″N 103°54′01″E﻿ / ﻿1.394564°N 103.900156°E﻿ / 1.394564; 103.900156 |
| SE2 | Rumbia | 18 January 2003; 22 years ago | Named after the Rumbia plants: Sagu Rumbia and Buah Rumbia. | 1°23′27.94″N 103°54′22.70″E﻿ / ﻿1.3910944°N 103.9063056°E﻿ / 1.3910944; 103.9063056 |
| SE3 | Bakau | 18 January 2003; 22 years ago | Named after the Bakau wood used for building foundations. | 1°23′16.27″N 103°54′18.96″E﻿ / ﻿1.3878528°N 103.9052667°E﻿ / 1.3878528; 103.9052667 |
| SE4 | Kangkar | 18 January 2003; 22 years ago | "Kangkar" refers to a former fishery in the area. | 1°23′1.46″N 103°54′7.90″E﻿ / ﻿1.3837389°N 103.9021944°E﻿ / 1.3837389; 103.9021944 |
| SE5 | Ranggung | 18 January 2003; 22 years ago | "Ranggung" refers to a species of stork residing on the Punggol shore. | 1°23′1.03″N 103°53′51.85″E﻿ / ﻿1.3836194°N 103.8977361°E﻿ / 1.3836194; 103.8977361 |
| West Loop ||||||
| SW1 | Cheng Lim | 1 January 2013; 12 years ago | Named after the former Cheng Lim Farmway and Lorong Cheng Lim, where farms formerly existed. The roads in turn are named after Goh Cheng Lim, director of Kim Hock Hoe Ltd, a company of ship owners and commission agents. | 1°23′47″N 103°53′37″E﻿ / ﻿1.3963098°N 103.8937126°E﻿ / 1.3963098; 103.8937126 |
| SW2 | Farmway | 15 November 2007; 17 years ago | Named after the former Cheng Lim Farmway and Lorong Cheng Lim, where farms formerly existed. The roads in turn are named after Goh Cheng Lim, director of Kim Hock Hoe Ltd, a company of ship owners and commission agents. | 1°23′56.32″N 103°53′20.08″E﻿ / ﻿1.3989778°N 103.8889111°E﻿ / 1.3989778; 103.8889111 |
| SW3 | Kupang | 27 June 2015; 9 years ago | Named after the practice of Kupang fishing. Kupang means "mussels" in Malay. | 1°23′57.22″N 103°52′52.75″E﻿ / ﻿1.3992278°N 103.8813194°E﻿ / 1.3992278; 103.8813194 |
| SW4 | Thanggam | 29 January 2005; 20 years ago | The name means "Gold" in Tamil. A pedestrian bridge connects the station to Jalan Kayu. | 1°23′57.68″N 103°52′29.26″E﻿ / ﻿1.3993556°N 103.8747944°E﻿ / 1.3993556; 103.8747944 |
| SW5 | Fernvale | 29 January 2005; 20 years ago | The station was planned to be integrated with a commercial building. The station is close to the Selatar Mall, which opened on 28 November 2014. | 1°23′35.55″N 103°52′34.69″E﻿ / ﻿1.3932083°N 103.8763028°E﻿ / 1.3932083; 103.8763028 |
| SW6 | Layar | 29 January 2005; 20 years ago | The name means "To sail" in Malay. | 1°23′38.49″N 103°52′47.11″E﻿ / ﻿1.3940250°N 103.8797528°E﻿ / 1.3940250; 103.8797528 |
| SW7 | Tongkang | 29 January 2005; 20 years ago | The name refers to a small boat transporting goods along rivers. | 1°23′27.88″N 103°53′08.78″E﻿ / ﻿1.3910778°N 103.8857722°E﻿ / 1.3910778; 103.8857722 |
| SW8 | Renjong | 29 January 2005; 20 years ago | The name means "tall" and "to raise" in Malay. | 1°23′11.81″N 103°53′25.53″E﻿ / ﻿1.3866139°N 103.8904250°E﻿ / 1.3866139; 103.8904250 |

## Infrastructure
### Rolling stock

The Sengkang and Punggol LRT lines (SPLRT) utilise the Crystal Mover Automated People Mover (APM) rolling stock manufactured by Mitsubishi Heavy Industries. The rubber-tired trains are fully automatic and can accommodate up to 105 passengers per vehicle. The SPLRT has an initial fleet of 41 APMs, with 16 more APMs delivered under contract C810A. The APMs are configured for single car or two-car operations, with a maximum capacity of 36 trainsets on the network. In February 2022, the LTA ordered another fleet of 17 two-car APMs from Mitsubishi for S$439 million. This was followed by another order for eight more two-car trains in May 2023, costing S$87 million. The new trains are set to replace the 25 one-car trains and half of the 16 two-car trains, bringing the overall SPLRT fleet to 33 two-car APMs. The first two trainsets were delivered to Singapore on 23 November 2024 and are expected to commence operations in 2025.
The APMs have a top speed of 80 km/h (50 mph), with a maximum operational speed of 70 km/h (43 mph). They are powered by 750V DC third rail located on one side of the guideway. Each vehicle is 11.84 m (38.8 ft) long and 2.69 m (8.8 ft) wide. The exterior has a crystal-like design with a polyhedral nose reflective of its namesake. Mitsubishi describes the curved sides of the APM as a design choice to "soften" the sharpness of its polyhedral shape. The exterior is painted pearl white and indigo blue.
As driverless vehicles, the APMs do not include a driver cabin. Instead, detrainment doors at both ends of the cabin allow emergency evacuation of passengers onto the track. The emergency stop button and emergency notice system are located at the right-side corner of the vehicle's front, while line maps and service information are displayed on the left. The interior features white side panels and ceiling, a grey floor, grayish-blue seats, and handrails and grip bars accented in a wine color. The cabins are air-conditioned.
The SPLRT trains are maintained and stabled on the second floor of Sengkang Depot. Located between the Layar and Tongkang LRT stations, the depot also houses the trains of the North East line. Its facilitates include a two-story main building with an operation control center room, automatic vehicle washing facility, maintenance garage, departure inspection track, stabling yard, power receiving and transforming facilities, and a test track. The 3.5-hectare (8.6-acre) site is being expanded to 11.1 hectares (27 acres), which will include two more reception tracks and three new traction power substations to expand the depot's stabling and maintenance capacity.

### Train control and power system

The Sengkang LRT line is fully automatic, and is equipped with Kyosan APM fixed block signalling system. The line's automatic train control (ATC) is composed of automatic train protection (ATP) which ensure safe operations, automatic train operation (ATO) which controls the automatic operations, and automatic train supervision (ATS) for overall command, monitoring and recording of the system. To reduce equipment mass on the train, the onboard ATP and ATO systems are integrated into one unit, although for safety reasons, the function and control logic of the AVP and AVO systems remain independent. These subsystems are connected via LAN and managed by a computer-based interlocking (CBI) system that oversees traffic safety of the APM.
The power system of the SKLRT includes a 22kV AC power intake and distribution network, a 750V DC traction power system, and a 400V AC system for station services. Power is supplied via two 22kV AC feeders from the North East line to improve reliability and take advantage of the 66kV tariff. The AC supply is distributed through a closed ring network to prevent power disruptions during single outages. At each station, the AC supply is stepped down to 400V AC using service transformers for mechanical and electrical needs. Traction power substations (TPSS) further step down the 22kV AC to power rectifiers that convert it to 750V DC for train operations. Each TPSS is equipped with an inverter system to return excess energy from regenerative braking back to the 22kV distribution network. In 2004, the SKLRT has three TPSS, with one on standby to maintain operations during outages. Currently, five traction power substations (TPSS) are operational on the SKLRT. This number will increase to eight with the planned expansion of Sengkang Depot.

### Station facilities

All Sengkang LRT stations are equipped with lifts connecting passengers from the ground level to the station concourse, and from the concourse to the platform level. Each station also has at least one wider faregate for wheelchair users, and tactile flooring to guide the visually-impaired from the ground floor to the platforms. The stations are also equipped with fire extinguishers and fire phones. Emergency stop buttons on both sides of the station platform, when activated, cuts off traction power supply and halts incoming trains.
Fixed platform barriers installed by Chee Yam Contractor are intended to prevent commuters falling to the tracks. However, the barriers do not have doors and instead have fixed openings for boarding trains. The lack of doors have been criticised by a commuter as a "half-baked solution" and felt the barriers would instead restrict rescue efforts. Nevertheless, the limited space of the LRT platforms could not accommodate the power, communications and signal control rooms required for platform screen doors.
To enhance safety, SBS Transit has implemented the VAnGuard track intrusion detection system on the SPLRT. Using video analytics and artificial intelligence, the system monitors footage of tracks and platforms to identify individuals or objects on the tracks. When an intrusion is detected, operations control centre staff can press the emergency stop button to halt services along on a specific loop. The system also triggers an alarm when intruders or foreign objects are detected. In addition to track intrusions, the system can spot unattended items on station platforms, allowing staff to provide assistance or undertake security precautions.