ST Engineering/Linkker Electric Bus (Linkker 12 LF)

ST Engineering Electric Bus
(Linkker 12 LF)
ST Engineering Electric Bus
ST Engineering Electric Bus
Manufacturer Linkker (CKD); Gemilang Coachworks (Assembly)
Bodywork Linkker LinkLight
Years in operation 2021—
Operators TBA
Technical Data
Length 12 metre
Powertrain Linkker LinkDrive
Accessibility Low Floor
Emission Standard Zero tailpipe emissions

The ST Engineering/Linkker Electric Bus (final name TBC; likely Linkker 12 LF) is a fully electric, low-floor single-deck city bus offered by ST Engineering Land Systems, based on the Linkker 12 LF integral bus. Primary contractors include Finnish electric bus manufacturer Linkker for the electric drivetrain and bodywork, and Malaysian bodybuilder Gemilang Coachworks for the final assembly.

In a tender awarded to ST Engineering Land Systems, 20 units of these buses were procured by the Land Transport Authority in 2018 as part of efforts to build a more environmentally friendly public bus fleet. In total, 60 electric buses were procured from three separate manufacturers at a total sum of S$50.64 million.

These buses are also the first public buses in Singapore to be charged via overhead pantographs at bus interchanges. The full rollout was originally scheduled by end-2020, but has since been delayed to 2021. An autonomous variant of this bus is used for ST Engineering research and development, named the STROBO Series 12 Bus.

While the actual model name is uncertain, a Linkker presentation referred to its autonomous variant as a Linkker 12 LF.


ST Engineering Background (Click to expand)

ST Engineering is a Singapore-based integrated engineering group dealing in the aerospace, electronics, land systems and marine sectors; primarily engaging in defence applications. The company’s Land Systems division (formerly ST Kinetics) is established in the local bus industry as the local distributor for MAN buses (MAN A22, MAN A24 and MAN A95), of which many entered service in Singapore since 2011.

The company has also produced a 3-door concept single-deck bus and a 3-door concept double-deck bus, both of which commenced revenue service trials in 2017, and had refitted an existing diesel bus to an electric bus as a proof-of-concept. ST Engineering also secured an LTA contract for 3-door Euro 6 double-deck buses and is working with LTA to develop and trial fully-autonomous buses in the future.

For the bus industry, ST Engineering typically works with different manufacturers for fabrication and systems development. It has marketed city buses on MAN and Linkker chassis (most frequently with Gemilang Coachworks bodywork) and used Yinlong and BYD vehicles as platforms for autonomous vehicle development. ST Engineering is also the Asia Pacific distributor for Linkker electric buses.

For the ST Engineering/Linkker Electric Bus, aluminium bodywork and electric drivetrain components are procured from Linkker, an electric bus manufacturer from Finland. Linkker had previously tested its buses domestically (in Helsinki, Espoo, Turku) and overseas in Copenhagen and Moscow. Electric motors and inverters are supplied by Danfoss, a Denmark-based engineering group.

These buses are based on the Linkker 12 LF low-floor city bus. Unlike Linkker 12/12+ units operating in Europe, local units bear a significantly different exterior bodywork design (likely commissioned by ST Engineering). One unit was built by Linkker; the remaining 19 units were shipped as completely-knocked-down (CKD) kits and assembled at Gemilang Coachworks in Malaysia. (TBC)

The unique bodywork design is characterized by asymmetric front and rear body panel designs. The bus also uses 19.5-inch diameter tyre rims, which are perceptibly smaller than the 22.5-inch tyre rims on most buses.

The STROBO Series 12 Bus Autonomous Electric Buses, also built by a partnership of ST Engineering/Linkker/Gemilang Coachworks, bears a similar bodywork design with additional roof attachments. Like the STROBO Series 12, these buses are OppCharge-compatible, fully-low-floor and equipped with three doors for more efficient passenger movement.

Find out more about Electric Buses in Singapore here.

ST Engineering Electric Bus

Twenty units of the ST Engineering/Linkker Electric Bus were produced.

According to an online report, Linkker is reportedly building one completely-built-up (CBU) unit in Finland, and the remaining nineteen units are assembled by Gemilang Coachworks in Malaysia using completely-knocked-down (CKD) kits. All units are bodied with Linkker’s LinkLight aluminium bus body. The accuracy of this report cannot be ascertained; given the unnecessary nature of shipping CKD bus kits to Gemilang which also builds aluminium bus bodies.

A similar electric drivetrain was also fitted to the ST Engineering Retrofitted Electric Bus and the ST Engineering STROBO Series 12 autonomous bus.

Buses are registered from SG3070R to SG3089M.

Basic Technical Specifications (TBC)
Driveline Linkker LinkDrive electric driveline
Electric Motor Danfoss Editron EM-PMI375-T800-1600 (TBC)
Permanent Magnet assisted Synchronous Reluctance Motor (dual inverter)
Continuous power/torque of 139 kW / 828 Nm
Maximum power/torque of 231 kW / 2100 Nm
Battery Lithium Iron Phosphate batteries (177.5 kWh) (TBC)
Opportunity charging via inverted pantograph (Oppcharge) with secondary CCS2 plug-in charging capability
Up to 450 kW DC charging input
Bodywork Linkker or Gemilang bodywork (TBC)
Lightweight aluminium unibody construction; full-low-floor layout with 3 doors
Assembled by Gemilang Coachworks in Malaysia
Electronic Display Sign (EDS) Mobitec MobiLED Ultima Amber EDS (Front)
Gorba imotion LED.e TOPSMART EDS (Side & Rear)
Orange LED Matrix design
PIDS LAWO INFOtainment Passenger Information Display System (PIDS)
Interior-facing unit (29”) and exterior-facing unit (21.5”)
Interior & Exterior Speakers
ADAS ST Engineering DriveSafe Advanced Driver Assistance System (ADAS)
AFS TNT Surveillance Anti-Fatigue system (T-DA Driver Alert Camera)
Passenger Capacity 28 Seated + 55 Standing = 83 Passengers
2 Wheelchair Bays
Additional Specifications Eberspächer Sütrak AC136 G4 AE electric air-conditioning system
door systems
USB Charging Ports
Vogelsitze System 750/3 seats
Rooftop charging rails
for inverted pantograph charging (Oppcharge)

It is noted that the retrofitted electric bus has opted for Lithium Iron Phosphate (LFP) batteries, which differ from two existing Lithium-ion battery options offered with Linkker buses (LTO and NMC batteries).

Omitting in-depth technical comparisons between the three, LFP batteries are relatively cheaper, less toxic, and typically last longer as compared to other forms of Lithium-ion batteries. LFP batteries have also been widely adopted for electric buses, with the world’s leading electric bus manufacturers by sales volume (Yutong, BYD and Zhongtong) opting for LFP batteries.

Two overhead pantograph chargers were also installed at Bukit Panjang Integrated Transport Hub and Bedok Integrated Transport Hub to support the daily operations of these buses.

See Also: ST Engineering STROBO Series 12 Bus – Autonomous Electric Bus

Opportunity charging

Based around the concept of Opportunity charging, the ST Engineering Electric Bus is charged at the terminus of a bus route, where charging points (typically overhead charging) are erected. The bus is sufficiently recharged in a short amount of time (usually several minutes) before the bus continues on its next trip.

Volvo 7900 Electric at a OppCharge charging station in Sweden
Volvo 7900 Electric at an OppCharge charging station in Sweden

With fewer batteries required per bus, its advantages translate to a more spacious bus interior, lower environmental cost of battery production, and lower electricity consumption through reduced vehicle weight. Its disadvantages include the lack of deployment flexibility (on non-infrastructure-equipped routes) and the possible impact on bus operations should a charging station break down, and some redundancy is thus required, such as installing multiple chargers at terminating points.

Currently, efforts are focused on expanding the use of opportunity charging on suitable routes and the adoption of similar charging infrastructure between bus manufacturers, allowing multiple bus models to use the same charger.

The Opportunity Charging approach is favoured by European bus manufacturers. Conventional, depot-charged buses carry a large number of batteries on every bus to achieve sufficient operating range over a day’s worth of revenue service, and is the approach preferred by Chinese bus manufacturers.

Overhead pantograph

The ST Engineering Electric Buses are charged via overheard pantograph, based on the opportunity charging (OppCharge) platform.

ST Engineering Retrofitted Electric Bus (SG3100M) – Bukit Panjang ITH

OppCharge is an open and competition-neutral interface seeking to accelerate the adoption of electric buses by being compatible with multiple bus manufacturers, hence offering operators choice and flexibility of buses without the need to modify existing charging infrastructure. These overhead pylon chargers with extendable pantographs are usually installed at the end stops of bus routes, allowing buses to quickly receive a full charge in-between trips.

Charging is fully automatic and secured by a two-way WiFi communication sequence. The driver gets a clear indication in order to stop within the specified ± 200 mm from the reference point. The charging sequence is started by activating the parking brake, and the driver can interrupt it at any time.

Swiss-Swedish engineering group ABB supplied four 450 kW chargers with installation, civil works, project management and commissioning. These chargers would allow the electric buses to be quickly recharged in less than ten minutes at key bus interchanges with an automated rooftop connection.

A similar overhead charger was installed at Cleantech Park in support of the NTU-LTA-Volvo Autonomous Bus Trial. The Volvo 7900 Electric bus participating in the trial is OppCharge-compatible and is recharged with the ABB HVC 300P fast-charge system, which delivers 300 kW DC power.

Two overhead pantograph chargers were each installed at Bukit Panjang Integrated Transport Hub and Bedok Integrated Transport Hub.

See also: Installation of overhead bus chargers at Bedok and Bukit Panjang


Annexe – ST Engineering Partnership

The partnership was indicated in ST Engineering’s 2017 Annual Report, referred to as a “partnership with an Original Equipment Manufacturer (OEM) for electric buses to distribute electric buses in right-hand drive countries in Asia Pacific, including Singapore, Australia, Hong Kong, Indonesia, Malaysia, New Zealand and Thailand”.

ST Engineering-Linkker Projects:
External Links & References:

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11 thoughts on “ST Engineering/Linkker Electric Bus (Linkker 12 LF)

  • 8 March 2021 at 11:49 AM

    Already nearly a year since this bus has been in Singapore and still never debut.

  • 2 December 2020 at 6:24 AM

    10 ech for SBST BNDEP & SMRT KJDEP.

  • 12 May 2020 at 4:29 PM

    5 For SBST 5 For TTS 10 For SMRT

  • 23 February 2020 at 4:36 PM

    I love the design of the bus so when will this bus be readied to use in Singapore?


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