Alexander Dennis Enviro500
Kmbate201 001
A TransBus Enviro500 serving with Kowloon Motor Bus in Hong Kong.
Manufacturer TransBus/Alexander Dennis
Built at Chassis: Guildford, England
Bodywork: Falkirk, Scotland
Capacity Various customer options
Operator(s) Various operators worldwide
Length 11.3, 12.0, and 12.8 meters
(37, 40, and 42 foot)
Width 2.55 meters
(8.36 foot or 100 inches)
Height 4.2 or 4.3 meters
(13.77 or 14.1 foot)
Floor type Low floor
Doors 1 or 2 door
Weight 23,133.21 kg
(51,000 lbs)
Chassis Alexander Dennis Enviro500
3-axle Volvo B9TL
Engine(s) Cummins ISMe/ISM/ISLe (ADL Enviro500)
Volvo D9A/D9B (3-axle Volvo B9TL)
Power output Cummins: 330hp/335hp/340hp
Volvo: 300hp/310hp/340hp
Transmission Voith D864.5
ZF Friedrichshafen 6HP604C
Allison Transmission B500R
Options Various customer options

The Alexander Dennis Enviro500 (previously known as the TransBus Enviro500) is a tri-axle double-decker bus built by Alexander Dennis (formerly by TransBus) in the United Kingdom. It was unveiled in 2002 and is one of the Enviro-series bus models made by TransBus/Alexander Dennis.


The Dennis chassis for Enviro500 (also known as Trident E500[1]) was modified from Trident 3. It can be fitted with Cummins ISMe335 Euro III engine (later Cummins ISLe340 Euro IV/Euro V engine which uses AdBlue to reduce emission of nitrogen oxides through selective catalytic reduction process), or ISM-330 engine for the buses delivered to North America, and coupled to Voith DIWA864.3E 4-speed or ZF 5HP602 5-speed gearbox. Later Voith DIWA864.5 4-speed gearbox, ZF 6HP602 6-speed gearbox and Allison B500R 6-speed gearbox became available and now they are the standard configurations.

Initially only the 12-metre (40 ft)-long version of the Enviro500 was built, but in 2007 Alexander Dennis announced the production of the 12.8-metre-long version,[2] and an 11.3-metre-long variant followed in 2008.

Later Alexander Dennis developed the hybrid electric version of Enviro500, known as the Enviro500H, with GM-Allison's parallel hybrid drive system, it was unveiled in late 2008.[3][4]

The Enviro500 bodywork is also available with Volvo B9TL chassis.

External appearanceEdit

The body of the Enviro500 was based on the original style of the single-deck Enviro300, and the upper-deck frontal design was similar to the design used on the Plaxton President body.

The vehicle exceeded some design limitations in Hong Kong, prompting the local Transport Department to make some exclusions in order to make the buses available to KMB on time.

  • The width of the bus is 2550 mm (100.3 inches), exceeded the limit of 2500 mm (98.4 inches). The width of 2550 mm, approved by the EU, became the current standard.
  • A fixed glass replaced the emergency door at the rear of the upper deck, but with more hammers available for emergency.
  • The front indicators are the smallest of all current models of Kowloon Motor Bus.

The facelifted version of Enviro500 body, first built in late 2003, have revised frontal and rear designs.

Hong KongEdit


Two KMB Enviro500, ATE140 LJ5724 (left) and ATE233 ME8594 (right) seen on route 1A. ATE233 is the second bus in KMB to use the new modified bodywork (the first bus is AVBE1 LU3721).

ATE staircase

The staircase of the Enviro500 of KMB.


Enviro500 of Long Win Bus

CTB 8103

Enviro500 of Citybus

MTR E500 804

Enviro500 of MTR

The Enviro500 and is designed and built according to current European standards and the operating environment of Hong Kong.

Kowloon Motor BusEdit

The Enviro500 is the first model of second-generation low-floor buses for Kowloon Motor Bus, with straight staircase and plug door (only at the exit) fitted. All KMB's Enviro500 buses had a bronze band added to the champagne livery to differentiate them from the first-generation low-floor buses.

When TransBus announced the development of the Enviro500, KMB became the launch customer by switching the last 20 of an order of 100 Dennis Trident 3 to the Enviro500 in 2002. Later in the same year, KMB placed a second order for a further 100 of the vehicles. The first Enviro500 arrived in Hong Kong on 12 November 2002 and was registered in January 2003. The remaining 119 buses entered service between March 2003 and November 2003.

In 2003 KMB placed the third order for 65 Enviro500s, quickly followed by a further 50. The bodywork of these buses received a number of minor modifications. The first 112 buses entered service between November 2003 and June 2005, and the remaining three buses were registered by its subsidiary Long Win Bus.

Due to the commencement of the KCR West Rail in late 2003 and KCR Ma On Shan Raiin late 2004, Transport Department of Hong Kong requested KMB to reduce its fleet size, so the registration of these four batches of KMB Enviro500 were delayed and some of them were stored for a long time before entering service.

In 2005, KMB placed a further order for 25 more vehicles with modified bodywork and new Alexander Dennis badge, 24 of them (five had their electronic route destination displays supplied by Gorba]] instead of Hanover) entered service in early 2006. The last one, a Euro IV-engined prototype, with fleet number ATEU1 (originally ATE257), has entered service on 24 May 2006. In 2009, it reemerged as a Euro V-engined bus.[5]

In late 2005, KMB ordered 15 more buses which entered service in August 2006.

Later a batch of 9 buses with Euro IV engines was ordered for delivery in 2009, which entered service in mid-2009. One of them was fitted with luggage rack after body assembly. It was quickly followed by another batch of 46 buses for delivery in 2010, 20 of them were eventually diverted to Long Win Bus, and 15 buses entered service with KMB in mid-2010.

A batch of 35 buses with Euro V engines was ordered for delivery in 2010-2011.

Early WithdrawalEdit

In July 2008, one of KMB's Enviro500 [Fleet number ATE180 (LN5481)] was written off after being burnt out in KMB's depot in Tin Shui Wai on 31 March 2008.

Long Win BusEdit

Long Win Bus registered three Enviro500 buses, which were acquired from KMB, in August 2005 (with fleet number 801-803) to cope with the increased demand for bus services after the opening of Hong Kong Disneyland.

In late 2005, Long Win Bus ordered five more buses which had luggage racks fitted when new. The first four buses (804-807) entered service in June/July 2006. The last one (fleet number 601), which was fitted with coach seats, entered service in July 2006.

A further batch of seven buses with Euro IV engines had been ordered for delivery in 2009. The first six buses entered service in mid-late 2009. The last one, which was fitted with coach seats, entered service in October 2009. These were followed by further five buses, with the first four being registered in December 2009; the last one, which was fitted with coach seats, entered service in April 2010.

In 2010, Long Win Bus received twenty more Enviro500 buses with Euro IV engines. A batch of 6 buses with Euro V engines was ordered for delivery in 2010-2011.


Citybus ordered 10 Enviro500s with Euro IV engine and luggage racks, soon after its sister company New World First Bus's order. The first batch of chassis arrived Hong Kong in the third quarter of 2007 for body assembly in NWFB depot at Chong Fu Road. They entered service in December 2007/January 2008.

A further batch of 18 buses with Euro IV engines had been ordered for delivery in 2009, they entered service in 2009. They were followed by another 77 buses, they entered service in 2010-2011.


Kowloon-Canton Railway Corporation originally ordered 9 12-metre long Euro IV-engined Enviro500 buses in early 2007 for its Feeder Bus service.[6] The first completed bus arrived Hong Kong on November 24, 2007, then registered in February 2008 and entered service in March 2008; the rest of them entered service in March/April 2008.

Due to a railway merger between MTR and Kowloon-Canton Railway in late-2007, they are now operated by MTR Corporation for running MTR Feeder Bus (previously known as KCR Feeder Bus) routes.

Later a batch of 15 buses with Euro IV engines was ordered for delivery in 2009, they were first registered in April-August 2009. This was followed by another order for 9 buses.

New World First BusEdit

New World First Bus ordered 18 Enviro500 buses with Euro IV engine in early 2007.[6] 17 buses entered service in early/mid-2008, another one (fleet number 5504) was shipped to Australia in March 2008, after body assembly, for demonstration in several cities between April and May 2008, it finally entered service in June 2008.

In 2008 New World First Bus ordered twenty 11.3m-long buses with Euro IV engines for delivery in 2009. They entered service in July-October 2009. A further batch of twenty similar buses with Euro V engines entered service in early 2010.

In 2010, a batch of 24 12m-long buses with Euro V engines was ordered for delivery in 2010-2011. They entered service in January-May 2011.

CLP GroupEdit

CLP Group ordered 5 Enviro500 buses with Euro IV engines for its staff shuttle bus service in 2008. The specification is similar with Citybus's Enviro500, but without wheelchair place and standees. They entered service in June 2009.

North AmericaEdit


An Alexander Dennis Enviro500 owned by BC Transit

In 2004, Alexander Dennis started to explore the North American market for its Enviro500. The American version of Enviro500 have modified bodies and redesigned fuel tanks, which enable the straight staircase to be moved forward. Alexander Dennis built two left hand drive Enviro500 (one 12m-long bus and one 12.8m-long bus) for demonstration in the United States and Canada.

Bus operators which had evaluated the Enviro500 include Community Transit of Snohomish County, Washington (December 2005), Unitrans of Davis (January 2006, two weeks), OC Transpo of Ottawa (June 28 to July 12, 2006 and February 2007) and the San Francisco Municipal Railway of San Francisco (November 2007 to January 2008).[7]

Alexander Dennis also built one 12-metre Enviro500 demonstrator for long-term loan. It was first loaned to Community Transit between 2007 and 2009 which put it into service on August 1, 2007, the bus was used on commuter routes between Seattle and various points in Snohomish County during its first year in operation.[8] From September 2010, it was loaned to Strathcona County Transit on a one-year lease for the operator's one-year-long double-decker pilot project[9]. The pilot is part of an exploration of different high-capacity bus types to carry more passengers on the high-demand commuter routes, which are between Strathcona County and Edmonton; an articulated bus is also being evaluated as an alternative and there is no commitment to put any Alexander Dennis model or any double-decker design into permanent service. This bus becomes the first double-decker to be used for regular transit service in Alberta[10].

In late 2008, Alexander Dennis announced the assembly of the American version of Enviro500 by ElDorado National of the United States.[4]


GO Transit double-decker bus

An Alexander Dennis Enviro500 owned by GO Transit

BC Transit ordered nine Enviro500 which were allocated to Victoria, British Columbia and entered service in early 2005. Two of them had taken part in a promotional show in USA, which was organized by Alexander Dennis in January 2005, before entering service. These were followed by another 26 which entered service in 2008; sixteen of them were allocated to Victoria and the other ten were allocated to Kelowna. In 2009, BC Transit received one Enviro500H for evaluation.

GO Transit, Toronto's regional transit authority, has 22 12.8-metre long Enviro500s. Twelve were purchased in a C$10.835 million deal and they were introduced in early 2008. Ten extra units entered service in early 2009.

OC Transpo also purchased 3 Enviro500s for further testing, after two trials in 2006/2007. The first unit arrived in November 2008 and the city of Ottawa currently operates them on a variety of routes.

United StatesEdit

Deuce bus waiting to load passengers

An Enviro500 in Las Vegas

Open-top Enviro 500 in Washington DC

An open-top Enviro500 in Washington DC

SLO E500

Enviro 500 in SLO Transit

Unitrans 8185 001

Enviro 500 of Unitrans

Gray Line New York, owned by Coach USA ordered 20 open-top Enviro500 for its sightseeing operations in New York and put them into service in spring 2005, these were the first open-top Enviro500 built (another 13 would later be ordered). Gray Line also received three single-door Enviro500 in summer 2005 for operation in San Francisco.

Citizens Area Transit (now RTC Transit) of Las Vegas had its first 50 Enviro500s entered service by October 2005. The service, marketed as "The Deuce", runs along the Las Vegas Strip. Certain high-traffic routes, such as along Maryland Parkway and Nellis Boulevard, have also used these buses. They offer extra ventilation grilles outside engine compartment to cope with Nevada's dry climate and high temperature. Las Vegas's Enviro500s have the biggest air conditioning system ever created for a transit vehicle, with eight fans fitted on the air conditioning unit. As of October 2006, CAT had firm orders for another 41 of the type worth $29.8 million; these were delivered in late 2007. A further 40 had also been ordered for delivery in 2008; these were 12.8 meters long and had a second staircase to speed loading and unloading. All these vehicles were used for fixed-route operations, not for sightseeing operations.

Les Cars Rouges, a sightseeing company, ordered 16 open-top Enviro500 for sightseeing operations in the USA, delivery of these buses started in early 2007. Eight of the Enviro500 are destined for San Francisco, and the rest of them are destined for Washington D.C.

Community Transit put in an order for 23 12.8-meter-long buses for delivery in 2010[11] when the demonstrator was still on loan by the operator. These were later followed by another 97 for delivery in 2011/2012.

Unitrans (University of California, Davis) ordered two Enviro500 which were delivered in early 2010, these are the first batch of Enviro500s with the bodywork assembled by ElDorado National.

SLO Transit ordered one Enviro500 which entered service in late 2010.

Hele-On Bus introduced one 12.8m Enviro500 in the first half of 2011.


United KingdomEdit

In August 2008, First Glasgow ordered a batch of 25 to add to its existing 3-axle Volvo B7L/East Lancs Nordics. They were put into service between April and June 2009.

Enviro500 bodywork on Volvo B9TL chassisEdit

HK KMB Volvo B9TL NA8894

A Kowloon Motor Bus' Volvo B9TL with Enviro500 bodywork.

As of early 2009, Kowloon Motor Bus and Long Win Bus in Hong Kong and Dublin Bus of Ireland are operating buses with this combination. For more details, see Volvo B9TL.


See alsoEdit


External linksEdit

Smallwikipedialogo This page uses some content from Wikipedia. The original article was at Alexander Dennis Enviro500. The list of authors can be seen in the page history. As with Tractor & Construction Plant Wiki, the text of Wikipedia is available under the Creative Commons by Attribution License and/or GNU Free Documentation License. Please check page history for when the original article was copied to Wikia

Community content is available under CC-BY-SA unless otherwise noted.