The Alexander Dennis Enviro400 City is a low-floor

double-decker bus A double-decker bus is a bus that has two storeys or decks. Double-deckers are used primarily for commuter transport, but open-top models are used as sightseeing buses for tourists, and there are coaches too for long-distance travel. They app ...

produced by the British bus manufacturer

Alexander Dennis Alexander Dennis is a British bus manufacturing company based in Larbert, Scotland. The largest bus and coach manufacturer in the United Kingdom, with a 50% market share in 2019, it has manufacturing plants and partnerships in Canada, China, ...

since 2015, as an alternative to the standard

Alexander Dennis Enviro400 MMC The Alexander Dennis Enviro400 MMC (sold as the Alexander Dennis Enviro400) is a low-floor bus, low-floor double-decker bus produced by the British bus manufacturer Alexander Dennis since 2014, replacing the Alexander Dennis Enviro400. The Envir ...

bodywork. The Enviro400 City is produced at Alexander Dennis'

Falkirk Falkirk ( ; ; ) is a town in the Central Lowlands of Scotland, historically within the county of Stirlingshire. It lies in the Forth Valley, northwest of Edinburgh and northeast of Glasgow. Falkirk had a resident population of 32,422 at the ...

and

Scarborough Scarborough or Scarboro may refer to: People * Scarborough (surname) * Earl of Scarbrough Places Australia * Scarborough, Western Australia, suburb of Perth * Scarborough, New South Wales, suburb of Wollongong * Scarborough, Queensland, sub ...

factories in the United Kingdom. It is available as a complete integral diesel or

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

bus, as well as the Enviro400EV complete integral

battery electric bus A battery electric bus is an electric bus that is driven by an electric motor and obtains energy from on-board batteries. Many trolleybuses use batteries as an auxiliary or emergency power source. Battery electric buses offer the potential for z ...

Scania N280UD The Scania N series is a line of low-floor bus chassis with straight-up, transversely mounted Euro IV or newer engine at the rear, built by Scania since 2006, replacing the Scania N94. It is available as the N UB (N230UB, N270UB, N280UB) two-axl ...

compressed natural gas Compressed natural gas (CNG) is a fuel gas mainly composed of methane (CH4), compressed to less than 1% of the volume it occupies at standard atmospheric pressure. It is stored and distributed in hard containers at a pressure of , usually in ...

-powered chassis.

Introduction

The Enviro400 City can trace its design roots back to 1997, with the introduction of the

Dennis Trident 2 The Dennis Trident 2 (the 2 standing for 2-axle) is a 2-axle low-floor double-decker bus chassis originally manufactured by Dennis, which was unveiled in 1997 and replaced the Dennis Arrow. It was built by TransBus after Dennis was incorporat ...

, one of the first low-floor double-decker buses to enter service. The model saw immense success at the turn of the millennium, despite financial difficulties facing

Dennis Specialist Vehicles Dennis Specialist Vehicles was an English manufacturer of commercial vehicles based in Guildford, building buses, fire engines, lorries (trucks) and municipal vehicles such as dustcarts. All vehicles were made to order to the customer's require ...

during this period. As a result of these, production of the Trident 2 passed first to

TransBus International Alexander Dennis is a British bus manufacturing company based in Larbert, Scotland. The largest bus and coach manufacturer in the United Kingdom, with a 50% market share in 2019, it has manufacturing plants and partnerships in Canada, China, ...

in 2001 and then to Alexander Dennis in 2004. Alexander Dennis updated the basic Trident 2 chassis to launch the

Alexander Dennis Enviro400 The Alexander Dennis Enviro400 is a twin-axle low-floor double-decker bus that was built by the British bus manufacturer Alexander Dennis between 2005 and 2018. It replaced the Alexander ALX400 (from which the Enviro400 was developed). In 201 ...

in 2005 – the basic chassis was still internally badged as a Trident. A second-generation Enviro400 was launched in 2009, with facelifted styling and updated chassis design, which finally dropped the Trident moniker. The second-generation Enviro400 was overhauled again to create the Enviro400 MMC, which was launched as the classic model's eventual replacement in 2014. Production of the Enviro400 ceased in 2018. In late 2015, Alexander Dennis launched the Enviro400 City, a premium model of the Enviro400 MMC, featuring a restyled front end to match the single-decker

Enviro200 MMC The Alexander Dennis Enviro200 MMC, also marketed as the Alexander Dennis Enviro200, is a single-decker city bus produced by Alexander Dennis since 2014 as the successor to the Enviro200 midibus and Enviro300 full-size bus. The Enviro200 MMC i ...

and a glass staircase as standard amongst other features, designed to compete with the

New Routemaster The New Routemaster, originally referred to as the New Bus for London and colloquially as the Borismaster or Boris Bus, is a low-floor Hybrid electric bus, hybrid diesel–electric double-decker bus operated in London, England. Designed by Tho ...

and

Wright SRM The Wright SRM (Son of Route Master) is a twin-axle double-decker bus body manufactured by Wrightbus in 2016, designed for the Volvo B5LH and Volvo B5LHC hybrid chassis. The design is based on the New Routemaster, sharing the majority of bod ...

designs in the

London bus Buses have been used as a mode of public transport in London since 1829, when George Shillibeer started operating a horse-drawn ''omnibus'' service from Paddington to the City of London. In the decades since their introduction, the red London ...

market.

Powertrain variants

Conventional diesel

Stagecoach Manchester 11903 YX74OMF 112 20241210

Blackpool Transport Blackpool Transport Services LimitedCompanies House extract com ...

became the first operator outside

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

to order the Enviro400 City on conventional diesel-powered chassis in January 2016, with the new buses upgrading the operator's 9 service to high-specification 'Palladium' standard. Other orders were delivered to Uno of

Hertfordshire Hertfordshire ( or ; often abbreviated Herts) is a ceremonial county in the East of England and one of the home counties. It borders Bedfordshire to the north-west, Cambridgeshire to the north-east, Essex to the east, Greater London to the ...

in 2017, branded for '' The Comet'' routes 614 and 644;

Arriva Buses Wales Arriva Buses Wales () is a bus operator providing services in northern Wales and Chester in northern England. It is a subsidiary of Arriva UK Bus. History Crosville Motor Services was formed in 1919 and operated services in Wales and northe ...

, with 13 buses also delivered in 2017 for

Arriva Sapphire Arriva Sapphire is a luxury brand used by various Arriva bus subsidiaries in the United Kingdom. History In February 2013, Arriva UK Bus announced that it would launch a Luxury service under the Sapphire brand for its bus services in the U ...

services in

Wrexham Wrexham ( ; ) is a city status in the United Kingdom, city in the North East Wales, north-east of Wales. It lies between the Cambrian Mountains, Welsh mountains and the lower River Dee, Wales, Dee Valley, near the England–Wales border, borde ...

;

Plymouth Citybus Plymouth CitybusCompanies House extract company no 2004966

, which ordered 27 for its busier services (16 in 2017, with all but one featuring 'Spark' route branding for the 21/21A/21B services; and 11 in 2019, predominantly used on the 42/42A/42C services); Bluestar, which had 20 delivered in 2018 for its 18 service, and

First Glasgow First Glasgow is the largest bus company serving the Greater Glasgow area in Scotland. It is a subsidiary of FirstGroup. The company operates within the area covered by the Strathclyde Partnership for Transport, a public body responsible for h ...

, with 10 for its

500 Glasgow Airport Express Route 500, or Glasgow Airport Express is a bus route in Glasgow that operates between the city centre and Glasgow Airport. History The Service has been operated by several bus operators through the years but as of 2025 the service is operated ...

in 2019. Two Enviro400 City buses were uniquely built for high-specification private hire use for the independent operator Southern Transit in April 2018, nicknamed 'Citymasters' by the operator. Another was delivered to

Delaine Buses Delaine BusesCompanies House extract company no 367317
Delain ...

in October 2023, the operator's first new Alexander Dennis double-decker, with two more delivered between September 2024 and March 2025. In February 2023,

Reading Buses Reading Transport Limited, trading as Reading Buses, is an English Municipal bus company, municipal bus operator owned by Reading Borough Council, serving the towns of Reading, Berkshire, Reading, Bracknell, Newbury, Berkshire, Newbury, Slough, ...

ordered seven Enviro400 City buses, the first of the type to be built to this length, intended to be built with high-specification interiors with 76 seats for use on Green Line bus routes 702 and 703. These were delivered in June 2023 and coincided with routes 702 and 703 being rebranded the London Line and the Flight Line respectively. A further nine Enviro400 City buses were delivered in February 2024 for use on the Reading to

Bracknell Bracknell () is a town and civil parish in Berkshire, England, the westernmost area within the Greater London Built-up Area, Greater London Urban Area and the administrative centre of the borough of Bracknell Forest. It lies to the east of Re ...

'Lion' 4 and X4 services, followed in December 2024 by 15 more for use on 'jet black' route 1. Nineteen Scania N250UDs with Enviro400 City bodies were delivered to

First Eastern Counties First Bus East of England is a bus operator that provides services in Norfolk and Suffolk in eastern England; it is a subsidiary of FirstGroup. It has five depots in operating areas spread out across East Anglia: Norwich, Ipswich, Great Yarmou ...

for their flagship 'Excel' services in 2020, featuring high-specification interiors, next stop announcements and camera mirrors.

Enviro400H/ER

The Enviro400 City was initially launched on the Enviro400H

hybrid electric A hybrid electric vehicle (HEV) is a type of hybrid vehicle that couples a conventional internal combustion engine (ICE) with one or more electric engines into a combined propulsion system. The presence of the electric powertrain, which has i ...

platform developed by Alexander Dennis and

BAE Systems BAE Systems plc is a British Multinational corporation, multinational Aerospace industry, aerospace, military technology, military and information security company, based in London. It is the largest manufacturer in Britain as of 2017. It is ...

, which was carried over from the previous Enviro400. The first production examples of the Enviro400 City entered service with

Arriva London Arriva London is a bus operator operating primarily in Greater London and partially in Essex, Hertfordshire, Kent and Surrey. It is a subsidiary of Arriva UK Bus and operates services for London Buses under contract to Transport for London. Oper ...

route 78 The following highways are numbered 78: International * AH78, Asian Highway 78 * European route E78 Australia * Waterfall Way – New South Wales State Route B78 China * G78 Shantou–Kunming Expressway, G78 Expressway Greece * Greek Nati ...

; a repeat order in 2016 would later see this fleet grow to a total of 53 Enviro400 City hybrids. The

HCT Group HCT Group was a social enterprise providing transport services and community services in several areas of the United Kingdom. It was founded in 1982 as Hackney Community Transport in the London Borough of Hackney, to provide transport services f ...

bought the hybrid model for its

Transport for London Transport for London (TfL) is a local government body responsible for most of the transport network in London, United Kingdom. TfL is the successor organization of the London Passenger Transport Board, which was established in 1933, and His ...

'red bus' contracts, taking delivery of 47 of the type between 2016 and early 2017 for service on routes 26 and 388, then nine more for operation on route 20 in 2019.

Transport for Ireland The National Transport Authority () or NTA is the transport authority for Greater Dublin and the public transport licensing agency for Ireland. It was established under the provisions of the ''Dublin Transport Authority Act (2008)'' and the ''P ...

ordered 600 of the Enviro400ER model, the successor to the Enviro400H chassis launched in 2019. Delivery of the first 100 buses commenced in late 2020; all are to be supplied with City bodies.

Enviro400 City CBG

NOTTINGHAM CITY TRANSPORT - Flickr - secret coach park

The Enviro400 City CBG was launched in 2016 at the Euro Bus Expo, built on the

-powered chassis. The CBG

drivetrain A drivetrain (also frequently spelled as drive train or sometimes drive-train) or transmission system, is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the driv ...

was only available with the City body, although some earlier models were delivered with MMC bodies.

Nottingham City Transport Nottingham City Transport (NCT) is the major bus operator of the city of Nottingham, England. NCT operates extensively within Nottingham as well as beyond the city boundaries into Nottinghamshire county. Publicly owned, it is today the second ...

has been the largest customer for the Enviro400 City CBG, taking delivery of 120 between 2017 and 2019 as part of a major fleet renewal programme; this made the company the largest operator of double-decker

biogas Biogas is a gaseous renewable energy source produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste, Wastewater treatment, wastewater, and food waste. Biogas is produced by anaerobic ...

buses in the world. An additional 23 Enviro400 City CBGs have been ordered for delivery in summer 2022, which the operator expects to be its last. 22 Enviro400 CBGs with both MMC and City bodies also entered service with

between 2016 and 2018. First West of England initially ordered an Enviro400 City CBG for services in

Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...

in 2017, which was later followed by an order for 21 Enviro400 City CBGs for service on the Bristol

MetroBus Metrobus may refer to: Transport services Bus Rapid Transit *MetroBus (Bristol), a bus rapid transit system in Bristol, England, United Kingdom *Metrobus (Buenos Aires), a bus rapid transit system in Buenos Aires, Argentina *Metrobus (Istanbul), a ...

pink line ''m1''. Due to First's Bristol depots being unable to support the route at the time, the buses were originally subcontracted out to CT Plus Bristol, although eventually Lawrence Hill Depot was upgraded to service such buses, and in September 2022 the original fleet passed to First, following financial difficulties faced by CT Plus. A further 77 Enviro400 City CBGs entered service with First West of England in early 2020.

Enviro400EV

A battery electric variant built on the Enviro400 City body, known as the Enviro400EV was unveiled in partnership with

BYD Auto BYD Auto Co., Ltd. ( zh, s=比亚迪汽车, p=Bǐyàdí Qìchē) is the Automotive industry, automotive subsidiary of BYD Company, a publicly listed Chinese multinational manufacturing company. It manufactures passenger battery electric vehicle ...

in 2018. The Enviro400FCEV

fuel cell bus A fuel cell bus is a bus that uses a hydrogen fuel cell as its power source for Electric motor, electrically driven wheels, sometimes augmented in a Hybrid power, hybrid fashion with batteries or a supercapacitor. The only emission from the bus is ...

was launched in 2021, with production commencing a year later, while a second-generation Enviro400EV with restyled bodywork and new driveline technology was also launched in 2022.

References

External links

Alexander Dennis product descriptions for Enviro400 range
{{Alexander Dennis

Enviro400 City The Alexander Dennis Enviro400 City is a low-floor bus, low-floor double-decker bus produced by the British bus manufacturer Alexander Dennis since 2015, as an alternative to the standard Alexander Dennis Enviro400 MMC bodywork. The Enviro400 C ...

Double-decker buses Low-floor buses Vehicles introduced in 2014