The accreditation means the vehicle boasts the same green credentials as the latest diesel hybrid and alternative fuel buses.
The privately-owned bus was repowered with a Cummins ISB 4.5-litre Euro 6 diesel engine and its previous Allison transmission replaced with the new T2100 fully automatic version featuring FuelSense 2.0 Max – delivering fuel savings of up to 6% more than the original FuelSense software.
The conversion was carried out by Mitchell Powersystems, Allison’s UK distributor.
The same engine-transmission combination could enable other Routemaster buses to continue operating in the capital when London’s ultra-low emission zone (ULEZ) comes into force in 2019.
The last Routemaster was withdrawn from general service in 2005. This vehicle was purchased in 2007 by Sir Peter Hendy CBE, chairman of Network Rail and former commissioner of Transport for London, who drives the bus on special charity fundraising trips.
The LEB standard was introduced in 2015 by the Department for Transport. To comply, a bus must achieve a reduction of more than 15% in well-to-wheel greenhouse gas emissions (methane, carbon dioxide and nitrous oxide) compared with a Euro 5 diesel bus and must meet the Euro 6 engine standard in other emissions.