My vehicle for my inaugural journey on Thursday 9 July was 8804 (LJ57 YAW), though I understand it was delivered wearing registration LF07 CDN. Route 129 is a relatively short service for those operating in London and conforms to a 12-minute daytime frequency, with end-to-end journey times typically coming in at just over 20 minutes.
The engine runs at a constant rpm but picks up to a higher rpm when the bus sets off. It provides power to a battery, which in turn powers the traction motors. In some ways this bus is similar to a tram in that it uses electric motors. Acceleration was brisk - but only up to 20mph; thereafter, progress was painfully slow - reaching 30mph was some achievement, despite being unladen!
These vehicles are definitely not suited to hills or heavy loads. They are, however, much quieter than their conventional-engined sisters.
The Wright double-decker hybrids being introduced in London are dual-mode and can operate on battery power only (at low speeds) or the engine (which cuts in at 15-20kph using an efficient five-litre unit) or both systems together. This will in theory give the vehicle the same abilities as standard double-deckers but with better fuel consumption and emissions.
Originally, there were only two types of hybrid bus built by Ballymena-based Wrightbus, one based on the chassis of a Dennis Dart SLF and the other on that of a DAF (later VDL) SB120. These were at the cutting-edge of engine design when first unveiled as nothing similar had been produced in such quantities. The first order for vehicles of this type was by TfL for its route 360, operated by Go-Ahead Group's London Central subsidiary, entering service in the capital during early 2006. The recipient had originally ordered the new, competing TransBus Enviro200H, though the latter's insolvency saw TfL become impatient and Wright's equivalent was ordered instead, based on the VDL SB120 chassis.
These were followed by those operating the route on which I travelled today, commencing operation on route 129 back in November 2007, with a solitary example of this type arriving in early 2008 for London Central. (DB)