A red London bus with a BAE Systems hybrid-electric drive train was delivered to Transport for London and Metrobus, one of the city’s principal bus operators.

The bus, a double-deck model built by Britain’s Alexander Dennis Limited (ADL), is among 17 hybrid units built by ADL and BAE Systems that will be evaluated in passenger service starting later this year.

Delivery of the bus at Euro Bus Expo 2008 in Birmingham, U.K., marks the introduction of BAE Systems’ HybriDrive propulsion technology to the European market. The diesel-electric drive system is already in use on more than 1,500 buses in North American cities.

The system reduces emissions and fuel consumption while meeting the durability requirements of demanding urban transit operations. It consists of a generator, an electric motor and an energy storage system managed by computerized controls. A diesel engine that turns the generator operates independently of the electric drive motor, allowing it to run at nearly consistent speed for optimum efficiency.