Dennis Trident 3

Dennis Trident
SBST Dennis Trident
SBST Dennis Trident
Manufacturer Dennis Specialist Vehicles
Bodywork Duple Metsec DM5000
Years in operation 2001–
Operators SBS Transit
Technical Data
Length 12 metre
Engine Cummins M11-305E
Transmission Voith DIWA 863.3
Accessibility Low Floor
Emission Standard Euro II

The Dennis Trident is a rear-engined low-floor double-deck transit bus built by Dennis Specialist Vehicles. It is also the first low floor double-deck bus chassis built by Dennis, and was particularly successful in the Hong Kong market.

Singapore Bus Services (now SBS Transit) ordered 20 Dennis Tridents with Duple Metsec DM5000 bodywork in 1998, and were registered in 2001. These were of the 3-axle 12-metre configuration.

Design:

The Trident series of chassis was developed by Dennis Specialist Vehicles based on their Dennis Lance. It has a longitudinally mounted rear engine in RR layout similar to the then mass-produced Volvo Olympians, but with the middle axle being the drive axle. An auxiliary axle mounted behind the second axle to cope with the weight at the rear and reduce the length of the rear overhang.

The three-axle variant of the Dennis Trident was known as the Dennis Trident 3. Four different chassis lengths were available: 10.3m, 10.6m, 11.3m and 12m. It could be fitted with the Alexander ALX500 or Duple Metsec DM5000 bodywork. Voith DIWA and ZF Ecomat transmission options were available.

Production of the Dennis Trident 3 began in 1997, and continued through 2001 when the company underwent several mergers and rebranded to TransBus International. In 2002, a modified version of the Trident 3 chassis was incorporated into a completely new bus marketed as the TransBus Enviro500, which ultimately became its successor. Production of the Trident 3 chassis ceased that same year.

The two-axle variant of the Dennis Trident (Trident 2) remained in production until 2006 when it was succeeded by the Alexander Dennis Enviro400. It also incorporated a modified Trident 2 chassis and was produced from 2005 onwards.

Technical Specifications

Engines for the Trident were all manufactured by American company Cummins. Originally supplied with the standard Euro II-compliant M11-305E engine delivering 305 horsepowers, later Euro III Tridents (built after 2001) used the Cummins ISMe engines delivering 330 or 335 horsepower. Gearbox options included the Voith DIWA 863.3 and ZF 5HP590, but the Voith DIWA 864.3E was later made available.


SBS Transit Dennis Trident 3 (SBS9671E – SBS9690A)

In 1998, Singapore Bus Services (SBS) placed orders for 20 units of the 12-metre Dennis Trident 3. They were registered between 6 Jul 2001 and 26 Nov 2001 as SBS9671E – SBS9690A.

Basic Technical Specifications
Engine Cummins M11-305E, 10824 cc, Euro II
Power rating of 305 hp (227 kW) @ 1900 rpm
Torque rating of 1559 Nm @ 1200 rpm
Transmission Voith DIWA 863.3 gearbox, three-speed automatic
Bodywork Duple Metsec DM5000 Bodywork
Supplied in completely knocked down (CKD) kits by Duple Metsec of United Kingdom. Assembled locally by SBS Engineering Pte Ltd.
EDS Electronic Display Signages (EDS) from Hanover / Shanghai CanRun Electron Tech / Transit Media 
Orange LED matrix design
Air-conditioning Denso rear-mounted air-conditioning unit
SBS Transit Dennis Trident III (SBS9673A)
SBS Transit Dennis Trident III (SBS9673A)

The Dennis Tridents were the first ever double-deck Dennis buses on Singapore roads. Ordered in 1998, the chassis were not built until late 1999 due to a large number of orders from Hong Kong bus operators, and these buses only entered revenue service in 2001. SBS had opted for similar specifications as the Hong Kong market, such as the Cummins M11, Euro II-compliant engine. The drive axle is the forward of the two rear axles, while the rear ‘tag’ axle has no steering capability.

Singapore’s Dennis Tridents are bodied with the last DM5000 body kits ever produced by Duple Metsec before being absorbed into a new company (Transbus International). By the time they had been assembled and registered in 2001, SBS had been re-branded as SBS Transit. These buses were equipped with Transit Media Electronic Display Signages (EDS) when they entered revenue service, a rarity for buses in that era, where traditional plastic route destination signs were preferred as a cost-saving measure (apart from a few prototypes and SBS9810X). It would only be until the introduction of Scania K230UBs where the widescale use of EDS displays would take off. Some Tridents had their original EDS units swapped with Shanghai CanRun Electron Tech and Cool-Air units.

These buses made their revenue service debut on 10 July 2001, when the first 10 units were deployed on Services 85, 111, and Express 502. They have been under the control of Hougang Bus Depot ever since their introduction and can be found running medium-to-long haul routes in northeastern Singapore, such as Services 51, 62, 64, 74, 80, 89 and 163.

SBS Transit Dennis Trident III - Upper Deck Interior (SBS9671E)
SBS Transit Dennis Trident III – Upper Deck Interior (SBS9671E)

Interior:

The Dennis Trident 3 has a licensed carrying capacity of 132 passengers, comprising 56 upper deck seating, 29 lower deck seating and 47 standing passengers. The upper deck was unique in having a single side-facing seat next to the staircase due to space constraints.

The low-floor design was step-less from the front door to the rear row of seats, built close to Hong Kong specifications. Despite the ability to accommodate wheelchairs, no wheelchair ramp was installed. “Bus Stopping” and “Doors Closing” indicators were similar to Hong Kong specifications, a unique feature retained to this day. Exit doors use similar closing chimes to their Hong Kong counterparts, and the illuminated “Doors Closing” sign comes in Traditional Chinese along with English.

SBST Dennis Trident (SBS9681B) - Service 80A
SBST Dennis Trident (SBS9681B) – Service 80A

Additional Specifications:

Some Dennis Tridents had their original Electronic Destination Signage (EDS) units replaced by different models such as CoolAir and Hanover.

With a small fleet of Tridents, it is easy to see that SBS Transit’s maintenance leaves much to be desired, as compared to their Trident counterparts operating in Hong Kong. Nevertheless, they are good, sturdy buses which will likely remain in operation for a long time.

EDS Specifications:

EDS Model Buses installed
Transit Media SBS9671E, SBS9675U, SBS9676S, SBS9678L, SBS9681B, SBS9682Z, SBS9685R,
SBS9686M, SBS9687K, SBS9688H, SBS9689E
Coolair SBS9672C, SBS9674Y, SBS9679J, SBS9680D, SBS9690A
Hanover SBS9673A, SBS9677P, SBS9683X, SBS9684T

Gallery

Interior photos on Page 2

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