Alexander Dennis drives on

By Doug Jack

Finding its headquarters at Falkirk, Scotland, “full to bursting” and urgently needing more space, Alexander Dennis held a major press conference in May at its new facility at Larbert, about four miles away.

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Volume production of single and double-decker buses for home and export markets will continue at the Falkirk factory. The Larbert factory will take over the preparation and packing of bodywork supplied in kits for assembly in overseas markets such as Hong Kong.

The stylish new Enviro400 to a London specification. The bar beside the upper-deck windshield is to deflect overhanging branches.
The stylish new Enviro400 to a London specification. The bar beside the upper-deck windshield is to deflect overhanging branches.

The main purpose of the press event was to launch a new two-axle double-decker bus for the British market. Though keeping the name Enviro400 with a resemblance in the styling, much of the vehicle is completely new.

Alexander Dennis knew when Euro 6 engine emission limits came into force this year, engines were certain to require larger cooling systems. They could have opted to re-engineer the existing model to accommodate the latest generation of engine, but instead opted to develop a completely new project.

Two new Enviro400 buses. The silver model is built to a lower height.
Two new Enviro400 buses. The silver model is built to a lower height.
A new Enviro400 in the course of construction. The upper deck pillars and roof are added later.
A new Enviro400 in the course of construction. The upper deck pillars and roof are added later.

Colin Robertson joined the company as CEO in March 2007. Since that time, he has led a major transformation of the company’s products and its relationships with its customers, and is fond of saying, “We must walk in our customer’s shoes.”

For this project, an engineering team tackled it from two directions. First, looking at the previous Enviro400 and going through all the service and warranty records, identifying features that could benefit from improvement.
Second, and much more significant, was to involve around 70 customers almost from the outset. They were not just fleet engineers, but chief executives, operational, maintenance, training and driving staff who attended a series of clinics as the project evolved. To my amazement, in a tight-knit industry in a small country by your standards, their involvement in the project, and knowledge of details did not leak to the public.

The new Enviro400 is available with three optional lengths, with a standard height of 14 feet, 2 inches, without any loss of internal headroom. There is the option of 13 feet, 10 inches. The shortest is a fraction under 34 feet and is designed for the London market where maneuverability is very important. It is the only version available with two double-width doors.

The compact staircase rises forward for safety reasons.
The compact staircase rises forward for safety reasons.

The second 35 feet, 9 inch, option length is the only model available at either height. The longest is 37 feet, 9 inches, with the capacity to seat up to 86 passengers.

Power for the new Enviro400 is from a Cummins 6.7-liter ISB Euro 6 engine developing 250bhp and mounted transversely at the rear. In order to comply with Euro 6 emission standards, it has Exhaust Gas Recirculation, Selective Catalytic Reduction, a variable geometry turbocharger and a diesel particulate filter.

The driving compartment with adjustable suspension seat, steering wheel and instrument binnacle.
The driving compartment with adjustable suspension seat, steering wheel and instrument binnacle.

Alexander Dennis offers a choice of ZF six-speed or Voith four-speed fully automatic gearboxes, both with integral retarders. The front axle is a ZF low beam and the rear axle is a ZF portal unit.

Electronic Braking System is standard, and a new feature is an Electronic Leveling Control that prevents the bus from settling on its suspension when it is stationary, for example in a depot.

One of the obvious benefits from the customer clinics is the ease of access to the engine and other mechanical components. The rear access doors open very wide, and can even be removed if preferred.

The rear view of the London specification bus.
The rear view of the London specification bus.

Entering the vehicle, the spaciousness is immediately apparent. Protected by a full width anti-vandal screen, the driver’s compartment has more room than before. The angle of the steering column is adjustable and the main instrument panel moves with it, so a driver of any height always has a clear view of the instruments.

The staircase, which the company calls a “squarecase,” is mounted over the offside front wheel. The compact design has two steps up to a lower platform, and up to the second platform and onto the upper deck gangway. This unit is made in one complete piece in GRP that does not leak or rattle. Generous handrails give good assistance to passengers.

At the top of the staircase, adjacent to the gangway is a large panel containing the main electrical systems for the vehicle. Safe from water ingress or accident damage, a technician can work comfortably inside the vehicle.

A Go Transit Enviro500 visited a recent exhibition in Dubai and created great interest.
A Go Transit Enviro500 visited a recent exhibition in Dubai and created great interest.

One of the most novel features of the Enviro400 is what Alexander Dennis describes as Quick Release Glazing.

Until now, on the main side windows, there was a choice between glass that could be held in place by rubber gaskets, or bonded glazing. If damaged glass had to be replaced, the process was relatively easy with gasket glazing, simply removing a rubber retaining strip, taking out the old glass and fitting in the new. However, gasket glazing looked rather ugly and old fashioned.

Simple tools enable glass to be replaced in around three minutes.
Simple tools enable glass to be replaced in around three minutes.

The problem with bonded glazing has been the time taken for the bonding of the new glass to be cured before the vehicle can go back into service.

With Quick Release Glazing, solid window frames are part of the structure of the bus and they give the attractive flush-fitting appearance of bonded glazing. If a glass needs to be replaced, it can be done from inside the vehicle by removing the trim strips from the top, bottom and each side and removing and replacing the glass using simple tools in a process that takes around three minutes. It is completely safe for the person carrying out the work and the method of securing also has the benefit of being vandal-proof.

The Quick Release Glazing will be welcomed by the industry.  It is quick, simple and safe.
The Quick Release Glazing will be welcomed by the industry. It is quick, simple and safe.

The engineering team also looked at heating and ventilation. The main unit now located under the staircase more or less centrally in the bus, ensures that warm air is evenly distributed throughout the vehicle. There is the option of a compact chill unit that can mount above the staircase for optimists who believe that there can be hot weather in the United Kingdom.
Some of the feedback from operators was about electrical systems. Instead of traditional long harnesses running the length of the vehicle, circuits have been split into shorter sections that enable faults to be diagnosed more easily and for any problem sections to be replaced.

Where cables pass through bulkheads, plugs on each side prevent the risk of the cables chafing. Similarly, there are no sensitive cables outside the vehicle and the new cabling is also more resistant to heat and corrosion.

At the launch, Colin Robertson said the new Enviro400 project had cost the equivalent of $12.5 million but he was also delighted to announce advance orders for 400 of the new buses, worth more than $130 million.

He took the opportunity to review the Alexander Dennis business. The company’s sales in 2013 were around $900 million, a three-fold increase from when he had first joined. ADL made a profit of more than $33 million, despite the high development costs of new models for Euro 6. International sales accounted for around 50 percent of turnover.

Colin said that the company would remain British but would continue to internationalize. The latest tri-axle Enviro500 was doing particularly well in a number of important export markets.

Colin is also very pleased with the way the North American business is developing.

“The lower height go-anywhere Enviro500 double decks are doing very well in Canada,” he says. “We will also be able to offer local assembly from the end of this year for any customers who need to comply with buy-American regulations. That work will be done by ABC Companies in its factory in Indiana.”

There are further exciting developments in the pipeline at Alexander Dennis and I hope to bring news of those later in the year.