The Alexander Dennis Enviro400 MMC is a low-floor double-decker bus produced by the British bus manufacturer Alexander Dennis since 2014, replacing the Alexander Dennis Enviro400. The Enviro400 MMC is produced at Alexander Dennis' Falkirk and Scarborough factories in the United Kingdom.
The Enviro400 MMC is available as a complete integral bus – including a premium model, the Enviro400 City – or as a bus bodywork on BYD, Scania and Volvo chassis. A tri-axle variant, known as the Enviro400 XLB, is also produced. The Enviro400 MMC is available powered by either Euro VI diesel, compressed natural gas (CNG), hybrid-electric or fully-electric powertrains.
The Enviro400 MMC can trace its design roots back to 1997, with the introduction of the Dennis Trident 2, 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 during this period. As a result of these, production of the Trident 2 passed first to TransBus International in 2001 and then to Alexander Dennis in 2004.
Alexander Dennis updated the basic Trident 2 chassis to launch the classic Enviro400 in 2005 – the basic chassis of which was initially still badged internally 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 classic Enviro400 ceased in 2018.
The Enviro400 MMC was unveiled by Alexander Dennis on 1 May 2014, as the eventual successor to the classic Enviro400. Compared to the classic Enviro400, changes included a complete body redesign with new front and rear ends and Euro VI engines as standard. The Oxford Bus Company was the first company to operate the Enviro400 MMC, followed by Go-Ahead, Stagecoach and Reading Buses.
The standard Enviro400 MMC is also available as a hybrid-electric integral, or as a body on Volvo B5LH hybrid chassis; examples of the latter are in service with Stagecoach East Scotland and Stagecoach London, while the former has seen widespread adoption with operators across London. The Enviro400 MMC body is also available on Scania chassis, as with the classic Enviro400, although now the updated Scania N250UD model is offered instead of the previous N230UD. Stagecoach became the first customer to operate the Enviro400 MMC on N250UD chassis in 2016, with deliveries to Stagecoach East Kent.
In 2015, National Express West Midlands took delivery of 106 Enviro400 MMCs, 58 of which were for its new high-specification Platinum range of services. Stagecoach is currently in the process of receiving a total of 136 examples for services with Stagecoach London, Stagecoach Manchester, Stagecoach South East, Stagecoach East Scotland and Stagecoach in Oxfordshire as well as a single demonstrator vehicle whilst Cardiff Bus has received 10 examples.
In 2016, National Express West Midlands took delivery of a further 96 examples for its expanding Platinum range of services; they were launched on routes 126 (Now X7/8), 529, X1, X2, X3, X4, X5, X14 and X61 (now withdrawn). In 2017, Southern Vectis took delivery of the MMC version to launch at the same time as its new ticket machines. National Express West Midlands again purchased a further 38 examples for its Platinum range. They were delivered throughout December 2017. All 38 were intended for the Harborne corridor in Birmingham, originally routes 22, 23, 24 and 29. In 2018, National Express West Midlands bought a further 72 Enviro400 MMCs for the West Midlands 9, 50, X10 and X70 and the Coventry 11 and 12X services.
Stagecoach East Midlands have placed 35 Enviro400 MMCs into service as of 2019. The first three buses arrived at Worksop depot in August 2016. The next batch of 15 buses entered service on newly-branded Simplibus services in Kingston upon Hull in October 2016. Six more Enviro400 MMCs entered service on Lincolnshire County Council-funded InterConnect cross-county services based out of Gainsborough depot in November 2017, painted in a purple variation of the standard Stagecoach livery. The final eleven buses entered service at Mansfield and Worksop depots in June 2018, branded for Nottingham to Chesterfield service the Pronto, operated jointly with Trentbarton. A further 17 Enviro400 MMCs have entered service with Stagecoach Yorkshire, the first nine of which entered service at Barnsley depot in September 2016 for Town Lines service 66. Eight more buses, delivered to luxury Stagecoach Gold specification for extended route X17 between Matlock, Chesterfield, Sheffield, Meadowhall and Barnsley, entered service in September 2018.
In October 2016, eight high-specification Enviro400 MMCs entered service at First West Yorkshire's Hunslet Park depot for First Express service X84 between Leeds and Skipton, branded as the Wharfedale Connection. Arriva Yorkshire placed 37 Enviro400 MMCs into service across their Castleford and Heckmondwike depots during the summer of 2017. Eleven of these were delivered to Arriva's luxury Sapphire standard for upgraded Castleford to Leeds services 163 and 166. The remainder were delivered in standard Arriva specification for Leeds to Wakefield route 189 (based at Castleford) and Leeds to Dewsbury and Halifax routes 254 and 255 (based at Heckmondwike)