Wrightbus to launch its new integral ‘decker at Euro Bus Expo

Long promised and long-awaited, next week operators will get their first chance to see Wrightbus’ new integral double-decker.

It is the latest logical step in an eight-year journey by the Northern Ireland-based firm, in its transition from a pure body-on-chassis builder to one that also offers complete bus manufacture in all major sectors.

With its integral single-decker product, the StreetLite; and its bespoke London ‘decker, the New Routemaster, on behalf of Transport for London (TfL); the StreetDeck will complete the present line-up.

And, while visitors to next week’s Euro Bus Expo will have their first chance to see a completed vehicle ready for delivery to a major operator, it has also announced the receipt of its first order for the design, ahead of the vehicle’s official launch at the show.

Go-Ahead-owned Brighton & Hove has ordered 24, to be delivered between February and April 2015, with a specification of 81 seats and an overall capacity of 90-plus. It has specified a Voith gearbox.

Says Go-Ahead Group Engineering Director Martin Harris: “We had the opportunity to see the vehicle in various stages of its development and have been particularly impressed by the design approach and fuel-efficient combination of the new technologies and lightweight materials.

“With our experience operating Wrightbus products over many years, we had no hesitation in placing an initial order, ahead of its official launch.”

All-new and complete

In its pre-show reveal to the press, Wrightbus said that with “class-leading weight and capacity, unmatched serviceability and whole life costs, a stunning new exterior styling, and excellent interior comfort for passengers and driver alike, StreetDeck is in every sense the complete double-deck bus.”

At the heart of the vehicle, StreetDeck has been designed to deliver “outstanding fuel economy and emissions” through a combination of low weight, efficient driveline configuration and technology advances that reduce auxiliary power consumption. The latter have already been proved in service with the StreetLite.

The new vehicle is set to become an important part of the Wrightbus Euro 6 product line-up, using many of the technologies and materials developed for the successful New Routemaster.

The chassis is assembled at the dedicated Wrightbus EN-Drive chassis facility in Antrim, with the body manufactured and built at the nearby main Wrightbus vehicle assembly facility at Ballymena.

The first pre-production StreetDeck being assembled at Ballymena
The first pre-production StreetDeck being assembled at Ballymena

StreetDeck has been developed using, as building blocks, a significant part of the technology developed for the New Routemaster. For instance, it shares the same front and rear modules, including front and rear axles, steering mechanism, steering, brakes and suspension units. In between is a new lightweight mid-section.

The StreetDeck uses the Gemini double-deck body style, further developed for Euro 6. With 73 seated passengers and 26 standees, StreetDeck has an overall capacity of 99 to TfL specification.

A single-door variant is also available for provincial operation and both are 10.47m long, 2.52m wide and 4.4m high.

Driveline options

The driveline uses the new Euro 6 Daimler OM934 5.1 litre 4-cylinder diesel engine, rated at 231hp and a maximum torque of 900Nm at 1,400rpm. There are three gearbox options: a Voith Diwa.6 four-speed auto, a ZF EcoLife six-speed auto (both with integral retarders) or the new Daimler G90 automated manual.

The engine is designed to deal with “extremely high” combustion pressures and has 20% longer maintenance intervals. Twin turbo performance and a constant power curve across an extremely broad engine speed range gives “exceptional driveability characteristics,” says Wrightbus, while engine oil and AdBlue consumption are 50% less than the engine’s Euro 5 predecessor.

A longitudinal driveline layout achieves improved efficiency, has less weight (thanks in part to the avoidance of an angle drive) and lower noise than conventional transverse engine configurations.

Mounted on a demountable ‘skid’ – a system developed for the StreetLite range – gives it excellent accessibility for servicing and maintenance, with plenty of space in the engine bay. A reduction in auxiliary power consumption is achieved by having separate coolant and charge air radiators with electric speed cooling fans.

The ride characteristics of the new StreetDeck are said to be “excellent” thanks to advanced axle and suspension systems. The front axle and suspension unit is the ZF RL75 EC independent suspension, using double wishbones with king post assembly, twin air springs and twin telescopic dampers. It has a 53-degree lock angle.

The rear unit is the ZF AV132 drop centre axle with two upper and lower radius rods, four wide-spaced air springs and four telescopic dampers mounted to bespoke suspension arms. An anti-roll bar gives a high-roll stiffness.

Serviceability has been a major area of focus for StreetDeck and significant enhancements have been made in a number of key areas, compared with the previous Gemini body.

This has included a reduction in the amount of different fixings to gain access to service areas, side engine doors opening through 180 degrees, ease of access to the AdBlue tank, destination boxes and headlamp units and ease of removal of heater box filters.

Crucially, around 1,000kg of weight has been removed compared with its Euro 5 Gemini predecessor, making it a sub-11T decker. While exact vehicle weights will vary according to specifications, two pre-production evaluation vehicles currently on test at Millbrook are 10,716kg (99 passenger capacity) and 10,468kg.

Striking looks

StreetDeck is been launched with a striking new look, giving the new vehicle extra ‘street appeal’, says Wrightbus. By basing the body on the existing and successful Gemini 3 body style, Wrightbus has been able to incorporate customer feedback and operating experience into the overall package.

Gemini 3 DNA follows through into some elements
Gemini 3 DNA follows through into some elements

An improved airflow throughout both saloons has been achieved, along with reduced solar gain in the upper saloon. Improvements in areas such as cab door lock design, wireless bell pushes and revised handpole fixings illustrate the attention to detail that has characterised the whole product development programme.

Rear has plenty of space for advertising or branding
Rear has plenty of space for advertising or branding

The glass panels on the staircase are an option, as Wrightbus recognises that some operators want space for ‘T’ ads. Enhanced driver visibility is offered thanks to a one-piece wrap-round windscreen and an improved signalling window. LED lighting, inside and out, is standard.

Innovation at heart

Speaking ahead of the public launch, Chairman & Chief Executive Mark Nodder says: “Innovation is at the heart of everything we do at the Wrights Group. So, like every new product development, the new StreetDeck has been designed and engineered with a passion and determination to be more than a bit special.

“We are leaders in the field of minimising fuel consumption, through weight reduction by design, the use of advanced materials and efficient driveline technology.

“All this, and more, is focused on achieving exceptional levels of quality, performance and safety, whilst delivering exceptional whole life cost value. With the new StreetDeck, we have harnessed all our group-wide resources, expertise and experience to bring to the market what, I truly believe is, the complete double-deck bus.”