The Dennis Trident 3, the three-axle version of the Dennis Trident, officially known as the Dennis Trident by KMB, is a three-axle, double-deck, low-floor bus chassis produced by Dennis Specialist Vehicles in the United Kingdom and was launched in 1997 as the first low-floor double-deck bus from Dennis Specialist Vehicles to replace the Dragon and Condor three-axle double-decker bus chassis from the same manufacturer.
Between 1997 and 2002, a total of 1,291 Dennis Trident buses were produced in Hong Kong. In 1998, Dennis introduced a two-axle version of the Trident, the Dennis Trident 2, with a transverse engine. Hong Kong's bus companies were unable to introduce this model due to the 16-tonne gross vehicle weight limit in Hong Kong at that time. It was not until 2009 that Hong Kong was finally able to introduce two-axle double-deck buses after the Transport Department granted a special exemption (i.e. an exemption permit) to the bus companies. Unfortunately, the Dennis Trident II was discontinued in 2006 and replaced by the Enviro 400.
Of the six franchised bus companies in Hong Kong, apart from CMB, the remaining five (including NWFB, whose franchise has ended) all owned Dennis Tridents between 2014 and 2015. Along with the Volvo Olympian (except NLB), Leyland Victory II, Dennis Dart (except Long Win Bus, LWB) and the BYD K9R (except CMB), this model has served on the largest number of Hong Kong's franchised buses on record (followed by the Enviro500, Enviro500 MMC and the Volvo B9TL), although all of them have been retired now.
Due to the reorganisation of the Dennis factory, the production line was taken over by TransBus International (now Alexander Dennis) in 2001. The Dennis Trident three-axle version was discontinued in 2002 and replaced by the Enviro500.
Design[]
The batch of Dennis Tridents which came out in 1999 or before has a 22.5" alloy with five large holes, and the tyre size is clearly marked as 305/70R 22.5.
Dennis Tridents manufactured in 1999 or later feature a 22.5" alloy with ten small holes.
The low-floor chassis of the Dennis Trident (of which the Euro 2 three-axle version was initially named the "Trident", and later the "Trident 3") was inspired by the Dennis Lance, with a Volvo Olympian-like chassis sidestand, providing great reinforcement and load carrying capacity. [1] The Dennis Trident was originally powered by a Euro II Cummins M11-305E (305bhp, 10,800cc), which was later changed to a Cummins ISMe-335 as the Euro III standard was implemented. The engine is rear-mounted and longitudinally arranged, with the centre axle as the drive shaft, which is more flexible than a three-axle bus with the rear axle as the drive shaft when cornering.
For the transmission, Voith is used as the pre-set option, with DIWA 863.3 3 three-speed, 864.3 (both third generation of DIWA series) or 864.3E (fourth generation) four-speed transmission. A ZF Ecomat 5HP590 (first generation of the Ecomat series) or Ecomat 2 5HP602C (second generation of the Ecomat series) five-speed gearbox is available as an option (the computer programme for the Ecomat 2 gearbox has since been modified to change the band to six-speed). The braking system is an all-wind, dual-circuit drum brake design with optional Anti-lock Braking System (ABS).
The Dennis Trident in Hong Kong is available in four lengths - 10.3m, 10.6m, 11.3m and 12m - and can be fitted with either an Alexander ALX500 or a Duple Metsec DM5000 body, with the ALX500 standing at 4.38m tall, and the DM5000 standing at 4.4m tall or 4.17m tall (in the special 10.3m short-bodied version), all with a width of 2.5m. However, the upper and lower doors of the DM-bodied buses are located too far back in the cab, making it more difficult for the driver to operate the vehicle, and the driver may have to strain his hand to reach the rear.
The axles were a Dana S75ULF headstock, a Dana centre axle (model unknown) and a Dana T75ULF[2] tailstock. The head axle suspension consists of two 305 mm diameter airbags and two shock absorbers, the centre axle suspension consists of four 255 mm diameter airbags and four shock absorbers, and the tail axle suspension has a leaf spring as the swing arm with two 255 mm diameter airbags and two shock absorbers[3]. The Dennis Trident, manufactured in 1999 or before, had five large holes in the alloy, while the other Dennis Tridents had ten small holes in the alloy. However, since all the tyres on this model are 305/70R 22.5 (where 22.5 means 22.5" diameter alloy), it is possible to mix and match stainless steel 22.5" alloy wheels.
Situation of sales in Hong Kong[]
In July 1998, when the new airport at Chek Lap Kok was officially opened and in operation, the Transport Department (TD), when inviting external tenders for the franchises of various bus routes, required the relevant bus companies to deploy air-conditioned double-decker low-floor buses to serve the routes. In September of the same year, NWFB was granted a franchise to take over the services of CMB (please refer to the article "1998 End of CMB Franchised Bus Service" for details), and the terms of the new franchise also required NWFB to introduce air-conditioned double-deck low-floor buses to serve the routes.
As only the Dennis Tridents manufactured by the Dennis met the relevant requirements at that time, Citybus and LWB, which were responsible for operating buses to and from the Airport and the urban areas, as well as NWFB, had a major hand in introducing Dennis Tridents. KMB also introduced a large number of Dennis Trident buses to replace its existing non-air-conditioned buses.
From 1997 to 2002, KMB, LWB, Citybus, NWFB and KCRC (now MTR) ordered 528, 151, 164, 426 and 22 Dennis Trident buses respectively, totalling 1,291 buses, which is the highest in the world.
In view of the large fleet of Dennis Trident buses in Hong Kong, this catalogue will be divided into sub-pages by bus companies, focusing on the information of the Dennis Trident batches purchased by each company:
| KMB | LWB | Citybus | NWFB | MTR Bus | NLB | KCB | Sun Bus |
Demonstrator bus[]
Chassis number: SFD111AR1TGT10101
Dennis built this test bus in 1995 and gave it an internal number (DT13). The car was built on an Alexander ALX500 body but still had the old Alexander RX front end, and was powered by a Cummins M11-305E engine and a Voith DIWA 863.3 gearbox. The prototype was sold to The Sun as a promotional bus, with the roof removed and the upper doors sealed, and the paintwork changed from grey to red with a promotional sticker. The bus was issued with licence plate M539 URX, special licence plate SUN 1 and N176WUP, and in August 2019 the bus was purchased by a Hong Kong bus conservation group and shipped to Hong Kong.
In August 2021, the bus was covered with a 31th birthday advertisement of Stanley Yau, a member of a Hong Kong popular male band MIRROR, and ran consecutively in different regions of Hong Kong for four days. [4]
Successing products[]
In 2002, the chassis of the Dennis Trident 3 was modified by TransBus International and fitted with an all-new body as the TransBus Enviro500 (now the Alexander Dennis Enviro500).
Related Articles[]
- Dennis Lance
- Enviro500
- Enviro400
- Volvo Super Olympian with the similar appearance
Notes and References[]
- ↑ 九巴丹尼士三叉戟型~亞歷山大 (KMB Dennis Trident ~ Alexander), Concorde Hobby Limited.
- ↑ http://www.taylornoonan.com/nextstop/tms_docs/Trident%20Specifications.pdf
- ↑ http://web.archive.org/web/20010302223539/http://www.dennisbus.com:80/pages/trident5.html
- ↑ "Stanley＠MIRROR生日 粉絲使15萬買巴士廣告賀壽" (Birthday of Stanley @ MIRROR: Fans bought $15m bus ad to celebrate his birthday), on.cc, 19 August 2021.
External Links[]
Dennis Trident 3 and Dennis Trident 2