NB4L enters service

By Doug Jack

The open rear platform closes off outside peak hours so one person can operate the bus.

NB4L is text-speak for the New Bus for London that Mayor Johnson promised when he took office in 2008. Transport for London is the city authority, which decides the total route network and the types of vehicles that will operate on them. Private contractors provide all the services, most for five-year terms.

London had acquired more than 400 articulated buses under the previous mayor, all from Mercedes-Benz. Known to Londoners as bendi-buses they were very good at picking up large numbers of passengers, particularly on busy commuter routes connecting with the main rail terminals. However, they were not ideally suited to London’s narrow streets and many junctions. Too often they could be held up half way across an intersection, blocking other traffic from moving.

London’s evening newspaper launched a campaign against the bendi-buses, which mayoral candidate Boris Johnson took up. He promised not only to get rid of the bendi-buses, he would also champion the development of a new generation of buses for the capital.

The Routemaster served London for many years. It was an almost indestructible double deck model with a front mounted engine alongside the driver who sat in a half width cab. It had an open platform at the rear that served both decks. They were popular because passengers could jump on and off when the vehicle stopped in traffic. A few still remain on two heritage routes principally used for sightseeing.

Boris Johnson won the election in 2008 and set about his promises with vigor. The last articulated buses came out of service towards the end of last year, replaced with standard double decks running more frequently to  make up for the loss in total passenger capacity.

A nearside view of the vehicle showing the three doors and the deeper windows on the lower deck so that standing passengers can see outside easily.
The interior is of a high standard. A wheelchair passenger parks facing rearwards against the padded board on the right.

He also launched a competition for a design for the New Bus for London. With the announcement of the winner, Johnson invited manufacturers to bid for building a prototype fleet of vehicles to the new design. The one catch was that Transport for London would have the rights to the design, as it would pay the full development costs.

Some might think this was a reasonable proposition, but it was unacceptable to major international manufacturers contributing many years of their highly valued and closely guarded technical expertise. In the end it came down to a straight contest between two British manufacturers; Alexander Dennis and the successful bidder, Wrightbus, based in Ballymena in Northern Ireland.

Transport for London introduced London-based Heatherwick Studio to work hand-in-hand with Wrightbus on the design. At the time Thomas Heatherwick was an unknown name in the automotive world.

It may have been tense for the free ranging mind of Thomas Heatherwick and his design colleagues to come up against the rigidity of the strict regulations of the European Union for driver and passenger safety. However, Mayor Johnson was determined to create a new icon for London, as well known as the previous red double deck buses and black taxicabs.

Wrightbus garnered a contract worth around $18 million to develop eight pre-production NB4L prototypes. The company and Heatherwick were up against the clock from the beginning, as the next Mayoral election in London is this May. Johnson wanted to have the prototype fleet in service and seen by millions of Londoners before the critical date.

NB 4L also had to meet the latest hybrid specification. Working closely with Siemens the company had its own patented light and strong aluminium construction system. Only the low-floor underframe is steel.
NB4L features three doors and two staircases. A double-width door is located at the front alongside the driver and ahead of the front axle. The second double-width door opens behind the front axle. One interesting feature is the traditional-styled open rear platform leading to a second staircase at the rear of the bus and into the lower deck. This door can close off so one driver can operate the vehicle during off-peak periods without a conductor to tend to the passengers and ticketing, which is effectively the same two-door layout as all other double deck buses running in London.

To accommodate the door and staircase arrangements the overall length came out to 36-ft 9-in, quite a bit longer than most other double deck buses running in the capital. The cleverly packaged hybrid drivetrain at the rear of the vehicle uses a compact 4.5 litre Cummins ISBe diesel engine that drives a generator to power the Siemens hybrid drive system. The rear axle drives with regenerative braking to recuperate energy stored in compact lithium-ion batteries.

I saw the first nearly complete prototype at Wrights factory in the spring of last year. It was certainly different and broke away from the rather square shape of most double deck buses. There is an abundance of glass, particularly around the staircases, and a deep lower front windshield. Its asymmetric styling and prominent round headlights look nearly retro in style.

The rear dome is most distinctive, almost totally panelled except for a curved glazing feature over the rear staircase. Unlike any other bus, it must surely meet the mayor’s wishes for an iconic design.

Wrightbus has its own well-established reputation for design and styling. Several British prepared to invest in up-market features have demonstrated that by making the passenger area more friendly and inviting more people will be tempted to travel by bus. The agency will recover the additional price in revenues.

Thomas Heatherwick traveled widely and looked at many buses old and new. His result looks very tasteful and of good quality with not a screw-head in sight. The vehicle has 40 seats on the upper deck, 22 downstairs and space for a further 25 standing passengers. The seat trim is in a warm-looking, hardwearing moquete. The stylish bronzed-color handrails are for passengers moving or standing in gangways. Some of the interior panelling is in the same traditional burgundy color as the original Routemaster but the lighting uses modern and longer-lasting LED.

Before entering service, the first of the prototypes underwent extensive proving at Millbrook testing grounds about 50 miles north of London. The facilities include the ability for test drivers to simulate one of Transport for London’s typical routes. They reckoned to achieve a fuel consumption of 11.6 mpg, which compares to approximately 5.8 mpg for a conventional diesel double deck bus. An imperial gallon is slightly larger than a U.S. gallon.

On the other hand, the price of the NB4L is equivalent to $520,000, compared with around $290,000 for a standard diesel bus. It will take a long time to recover that much higher initial cost, even allowing for the high price of diesel in the United Kingdom and other European countries.

Major political questions arise with Mayor Johnson standing for re-election in May. It is gearing up to be a very close contest with his predecessor, Ken Livingston who introduced the bendi-buses but also made many other major improvements to bus services in London. If Johnson is re-elected, will there be further orders for Borismasters, as some people call them, despite the higher price? If Ken Livingston wins he is far too shrewd a politician to bring back the bendi-buses, but would he sanction orders for a bus, which was very much a pet project of his predecessor? BR

Doug Jack is with Transport Resources in the United Kingdom.