Public Buses converted into COVID-19 Bus Transporters (COMET MAXI)

During the COVID-19 pandemic, 25 public buses were retrofitted into dedicated COVID-19 patient transport vehicles, known as COMET MAXI or COVID-19 Multi-Passenger Enhanced Transporter. the ‘MAXI‘ distinguishes the bus from other small vehicles used for patient transport, which were designated ‘midi’ and ‘mini’ (see: COMET article).

The COMET MAXI was the product of a collaboration between SMRT Corporation, HOPE Technik and Sheares Healthcare, with the support of Temasek Foundation. Buses were used to facilitate the mass transfer of COVID-19 patients between facilities, such as hospitals, dormitories and various community facilities. Other companies like ComfortDelGro, SBS Transit and Leisure Frontier joined afterwards.

In May 2020, twenty MAN A22 (Euro V) buses previously owned by SMRT Buses were converted into COMET MAXIs. These buses first entered revenue service in late 2011, and were re-registered as private buses. Each bus seats around 34 patients. During their COMET MAXI stint, buses were owned by Sheares Healthcare and operated by Strides Transportation.

In June 2020, five Scania K230UB buses owned by SBS Transit were retrofitted into COMET MAXIs, and joined the active COMET MAXI fleet the following month. These buses remained under SBS Transit ownership and were not re-registered as private buses.

Apart from public buses, private coaches later joined the COMET MAXI fleet. See the COMET article for more details.

As of 2021, the Sheares Healthcare-owned MAN A22 buses were sold to private bus operators.


Information regarding the collaboration was first shared on 25 April 2020, in a Facebook post by Temasek Holdings’ Chief Executive, Ho Ching, who then referred to buses as COVID-19 Bus Transporters. Initial photos show an SMRT MAN A22 undergoing conversion works, and up to 50 buses will similarly be converted (comprising 20 buses in the first batch, and 30 buses in a later batch). Converted buses are also re-registered as private buses. Ho Ching edited her Facebook post on 29 April 2020 reflecting several updates on the COMETs.

On 12 May 2020, a joint statement was issued by SMRT Corporation and partners Temasek Foundation, HOPE Technik and Sheares Healthcare, describing the features and operational details regarding the COMET MAXI fleet.

In June & July 2020, the COMET MAXI fleet was joined by retrofitted coaches from Leisure Frontier & public buses from SBS Transit. Similar privacy stickers, airtight driver cabin compartment divider, as well as a Negative Pressure System, were installed in these buses.


TRIGEN Automotive, the special function vehicle division of HOPE Technik, designed and engineered COMET MAXI’s features. HOPE Technik is a home-grown engineering firm with expertise in mechanical, electrical & electronics, and software engineering since 2006. Conversion works are undertaken by Liannex Corporation.

SMRT subsidiary Strides Transportation, a local limousine and premium bus service provider, oversees the operations, driver training and maintenance of the COMET MAXI fleet. Sheares Healthcare, which invests in and provides healthcare delivery services in Asia, owns the fleet of COMET MAXIs and liaises with the Ministry of Health to complement its patient transport services.

Interior Features

The COMET MAXI vehicles are converted from existing MAN A22 (Euro V) buses in SMRT’s fleet, and Scania K230UB buses in SBS Transit’s fleet.

According to SMRT, these (MAN A22) buses were chosen for their low-floor layout (for wheelchair accessibility), as well as being “relatively new… to make sure they are reliable on the road”⁠— despite being close to 9 years old.

Each bus takes two to three days to retrofit, and the modifications are ‘reversible’, according to TRIGEN Automotive.

As part of the modifications, an airtight floor-to-ceiling partition separates the rear passenger compartment from the front section of the bus. The dividing wall features windows and an emergency door for cross-compartment passage. Furthermore, the front compartment retains two wheel arch seats for the transport of accompanying medical or administrative personnel (such as paramedics, admin support manager, escort officer, etc) to be seated on board.

Each compartment is fitted with its own independent air-conditioning system, which prevents air circulation between both cabins. The passenger cabin is also equipped with a Negative Pressure System with a HEPA filter which ensures that only clean air is filtered out from the passengers’ compartment. This device is installed on the right side of the bus in place of a window (near the exit door) and protruding into the bus cabin; two seats are removed to accommodate the system. A differential pressure gauge is installed at the side of the front row seats.

The passenger cabin features safe distancing posters and individual seat numbers for each of the 34 seats. Hand sanitisers are provided at the exit door for passengers.

Finally, as part of conversion works, all revenue service equipment was removed from these buses.

Exterior Features

Prior to conversion works, MAN A22 buses were either painted in SMRT Buses’ Beige livery (18 buses); SMRT Buses’ Pixel Livery (SMB203S only); or LTA’s Lush Green livery (SMB208D only).

While converted buses entered COMET MAXI service in original liveries (with SMRT and SG♡Bus logos removed from the exterior of the vehicle), a small handful were repainted to a Silver livery, reminiscent of the silver base coat that formed SMRT Buses’ ‘pixel’ corporate livery launched in 2013. It later emerged that the Silver livery was a base coat for the final COMET MAXI livery (unveiled at a press event on 12 May 2020), which featured promotional decals on top of the silver base livery previously identified.

In summary, COMET MAXI MAN A22 buses have been identified in 4 different liveries: SMRT Beige, LTA Lush Green, Silver base livery, and COMET MAXI livery. All twenty MAN A22 buses were progressively repainted and restickered to the COMET MAXI livery.

As for the Scania K230UB buses, they originally bore the SBS Transit’s corporate livery in purple, red and white. They were vinyl wrapped with the COMET MAXI livery in a white base coat, as opposed to the more tedious and expensive process of repainting (as was done for the MAN A22 buses).

White perforated vinyl stickers are affixed to the retrofitted MAN A22 & Scania K230UB side and rear windows, similar to that used on bus advertising stickers, and are likely intended as privacy screens. The passenger compartment is almost completely enclosed by these stickers.

Active Deployment (2020)

The COMET MAXI fleet of buses is used to facilitate the mass transfer of passengers between facilities, including hospitals, dormitories and various community facilities. MAN A22 buses were deployed starting from 6 May 2020, according to the press release. SBS Transit buses were deployed starting from 3 July 2020.

Driver matters
COMET MAXI Driver in PPE (Photo: SMRT)

COMET MAXI drivers are not drawn from SMRT’s pool of bus drivers, but are specifically recruited for the job and must have a Class 4 drivers licence.

Prior to deployment, COMET MAXI drivers undergo 20 hours of training conducted by SMRT, including familiarisation with operating the vehicles’ retrofitted safety features. An additional two hours of training was conducted by the Singapore Civil Defence Force on the proper use of personal protective equipment (medical gown, gloves, and N95 mask) which drivers are required to put on while on duty.

Drivers do not come into contact with passengers, and vehicles are decontaminated after each deployment.

End of Operations

COMET operations were scaled down massively sometime around August/September 2020 with the decline of COVID-19 cases in workers’ dormitories. Disused MAN A22 COMET buses were spotted in various parking locations around Singapore, while SBS Transit parked its COMET buses at a corner of Ulu Pandan Depot.

Active Deployment (2021)

In 2021, ownership of 19 MAN A22 COMET buses (all except PC9040U) was transferred to Leons Automotive, a wholesaler of motor vehicles. These 19 units were then laid up in late April 2021, one year after they were registered as private buses.

PC9040U is currently operated by Cityline Travel, while currently retaining the COMET Maxi livery and the negative pressure system (NPS). The ownership of the bus itself is presumed to be a motor financing or leasing company that purchased the bus from Sheares Healthcare, and yet to be ascertained.

PC8969Y was unveiled in May 2021 to be operated by Leisure Frontier, bearing the company livery in white, orange, and red. The NPS was removed, along with the window privacy stickers. The two window seats (initially removed to facilitate the NPS installation) were reinstalled, but use red seat covers identical to those used on SBS Transit buses. It was taken out of layup and re-registered as PD7774T to Frontier Tours Pte Ltd in late May 2021, and subsequently transferred to the related entity of Leisure Frontier (S) Pte Ltd.


Retrofitted Buses

For MAN A22 buses that underwent COMET MAXI conversion in mid-200, their road tax was first suspended and reflected as Non-User Lay-Up status whilst awaiting or undergoing modification works.

In addition, the MAN A22 COMET MAXI buses were re-registered as Private Buses, bearing the Private Bus registration prefix of PC. This enables buses to be operated by Class 4 driving license holders, without requiring an Omnibus Driver Vocational Licence (ODVL). All buses were progressively repainted to the COMET MAXI livery, featuring a silver base coat with COMET MAXI identifying decals.

SBS Transit’s COMET MAXI-converted Scania K230UB buses retained their original registration numbers.

Public Buses converted to COMET MAXI (COVID-19 Multi-Passenger Enhanced Transporter)
SMRT Buses (MAN A22)
Former Registration (Public Bus)  New Registration (Private Bus)
SMB196D PC8932C
SMB197B PC9034M
SMB198Z PC8997R
SMB200A PC9271U
SMB201Y PC9089E
SMB202U PC9264R
SMB203S PC9064B
SMB204P PC9098D
SMB205L PC8948H
SMB206J PC9174S
SMB207G PC8941B
SMB208D PC9043L
SMB209B PC9054E
SMB210X PC9173U
SMB212R PC9255S
SMB214K PC9040U
SMB215H PC9263T
SMB217C PC8976B
SMB218A PC9078L
SMB219Y PC8969Y
SBS Transit (Scania K230UB)
Registration (Public Bus)
SBS8702G, SBS8856X, SBS8927A, SBS8939R & SBS8941H

The SMRT MAN A22 buses first entered revenue service in late 2011, while the converted SBS Transit Scania K230UB (Euro V) buses were first registered in July 2009.

In 2021, the former COMET MAXI MAN A22 buses were sold off to private bus operators.

Gallery: (MAN A22)

SMRT Beige Livery

Out of 20 MAN A22 buses, 18 of them first bore the SMRT Beige livery prior to COMET MAXI repainting.

Lush Green Livery

SMB208D was the only MAN A22 bus to bear the Lush Green livery prior to repainting.

Silver Base Livery

Interim livery prior to affixing of COMET MAXI decals.


Final livery for all COMET MAXI MAN A22 buses.

The ‘COMET MAXI’ logo is a gold heart that represents unity during the COVID-19 period and the desire to support the needs of the community during challenging times. The three COMET values are Care, Safety and Resilience.

Online circulated images

Exterior photograph is taken at the lobby of HOPE Technik in Penjuru.

Old corporate logos (i.e. SMRT) were removed from the exterior of the vehicle. Perforated vinyl stickers were affixed to the bus’ side and rear windows, similar to that used on bus advertising stickers, and are likely intended as privacy screens.

Gallery: (Scania K230UB)



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COMET MAXI Specifications at a glance

  MAN A22  Scania K230UB
Registration no. PC8932C; PC8941B; PC8948H; PC8969Y; PC8976B; PC8997R; PC9034M; PC9040U; PC9043L; PC9054E; PC9064B; PC9078L; PC9089E; PC9098D; PC9173U; PC9174S; PC9255S; PC9263T; PC9264R; PC9271U SBS8702G; SBS8856X; SBS8927A; SBS8939R; SBS8941H
Quantity 20 buses 5 buses
Owner / operator (2020-2021) Owned by Sheares Healthcare; operated by Strides Transportation
SBS Transit
Registration date April-May 2020 2009 (no change)
Technical Specifications
Bus Model MAN NL323F (A22) Scania K230UB
Engine MAN D2066 LUH-32 engine Scania DC9 35 230 engine
Emission Standard Euro V compliant via EGR / MAN PM-Kat® Euro V compliant via EGR
Transmission ZF EcoLife 6 AP 2000 B (6-speed) ZF Ecomat 6HP 504C (6-speed)
Bodywork MAN Lion’s City Hybrid  (Built under license by Gemilang Coachworks) Gemilang Coachworks
EDS Mobitec MobiLED (not in use) Hanover (not in use)
Air conditioning Independent air conditioning systems in both cabins
Unknown (front cabin);  Denso LD8u (rear cabin)
Doors Masats SMC Transit
Seating capacity Front cabin: 1 driver & 2 seated passengers
Rear cabin: 34 passengers & 1 wheelchair (excluding foldable seats)
Front cabin: 1 driver & 2 seated passengers
Rear cabin: 32 passengers & 1 wheelchair (excluding foldable seats)
COMET MAXI Modifications  
Retrofit company TRIGEN Automotive (a division of HOPE Technik) and Liannex Corporation
Specifications Front/rear cabin partition with emergency door
Rear cabin Negative Pressure System with HEPA filter
Perforated vinyl stickers for window privacy screens
Hand sanitisers
All revenue service equipment removed
Livery SMRT beige/red livery
LTA’s Lush Green livery
Silver base livery
COMET MAXI livery – featuring gold, black and red decals on repainted Silver base coat
COMET MAXI livery – stickered full-body wrap featuring gold, red and purple decals on White background

Other patient transport vehicles

Ho Ching’s Facebook post also called for Class 3 or Class 4 driving license holders to “volunteer to drive either the Comet-mini, or Comet-maxi.” Applicants may register their interest on

According to a Straits Times news article published 13 May 2020, about 45 buses were deployed to transport up to 600 Covid-19 patients daily, with the fleet formed of Lentor Ambulance and other commercial operators. The fleet was to be expanded to 60 in the coming weeks. However, a breakdown of the types of vehicles was not stated.

Other Conversions

Apart from this project, several initiatives have been taken around the world to convert buses for transporting COVID-19 patients.

Recently, in Neu-Ulm (Bavaria), Daimler Buses converted a Mercedes-Benz Citaro citybus into an intensive care patient transport vehicle, for the transfer of COVID-19 patients.

Article edit history:

This article originally implied that buses may be operating under their original SMB-prefixed registration plates as COVID-19 Bus Transporters, perhaps under a Special Purpose License or under an Exemption Order under the Road Traffic Act issued for the purpose of transporting COVID-19 patients. It has since been confirmed that they will be re-registered as private buses.

In addition, the article was also revised based on the new terminology of “Covid Multi-pax enhanced transporter” edited on Ho Ching’s Facebook post on 29 April 2020.

The official name “COMET MAXI” and further details are updated with the press release on 12 May 2020.

Scania K230UB information added on 16 June 2020, updated on 3 July 2020 reflecting new information from Ho Ching’s Facebook post.

Information history:

Information regarding the collaboration was first shared on 25 April 2020, in a Facebook post by Temasek Holdings’ Chief Executive, Ho Ching, who then referred to buses as COVID-19 Bus Transporters. Initial photos show an SMRT MAN A22 undergoing conversion works, and up to 50 buses will similarly be converted (comprising 20 buses in the first batch, and 30 buses in a later batch). Converted buses are also re-registered as private buses. Ho Ching edited her Facebook post on 29 April 2020 reflecting several updates on the COMETs.

On 12 May 2020, a joint statement was issued by SMRT Corporation and partners Temasek Foundation, HOPE Technik and Sheares Healthcare.

See Also:


51 thoughts on “Public Buses converted into COVID-19 Bus Transporters (COMET MAXI)

  • 3 March 2021 at 3:43 PM

    The bus could have a COMET bus on the screen where the bus number is shown🚍

  • 31 October 2020 at 11:41 PM

    When will the COMET-MAXI PC-plated MAN A22s get transferred back to SMRT for normal operations and change back to SMB?

    • 16 March 2021 at 8:31 AM

      And have the revenue equipments reinstalled back?

  • 12 September 2020 at 9:44 AM

    PC9054E is ex SMB209B

  • 19 June 2020 at 11:37 PM

    Heard some SBS plated Citaros from TTS and GAS will also join the COMET fleet

  • 19 May 2020 at 2:17 PM

    This buses after their covid19 stint maybe come like the fomer dennis lence buses used for Bus Plus services. Atleast its good its still under SMRT one way or another.

    • 27 May 2020 at 1:44 PM

      You must be ignorant to say under SMRT maintenance regime is good..In fact GAS/TTS maintenance is far more better than them..Just look at how they half hearted maintance those mini/maxi and TF50 buses


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