Autocar re-invents the Routemaster

The Routemaster’s open back kept the interior cool in the summer and stopped it getting stuffy in the winter. And the conductor was an ever-reassuring presence.So what was not to like? Even Ken Livingstone, London’s first modern-era Mayor, said that ‘only a de-humanised moron would get rid of the Routemaster’. So guess who decided to dump the Routemaster just weeks after winning a second election in 2004 and without mentioning it in his manifesto?

The last Routemaster – a 159 - was consigned to history in December 2005, some 44 years after the first. Although today, two ‘heritage’ Routemaster buses still ply a short route in central London to please the tourists.

Livingstone claimed EU disabled access regulations demanded the cull. When that turned out to be a lie (the cut-off date is actually 2017) it was claimed that Transport for London - know as Transport for Lefties by weary London commuters - that Routemasters were just ‘too small’.

Replacement of the Routemaster with generic double deckers and the hated – by everyone from passengers to cyclists - Bendy Bus has made surface public transport even more depressingly uniform and Stalinist than it needs to be.

So what has this got to do with Autocar? Well, we all appreciate good product design. How could we not, in this job? Everyday we see the huge design and engineering effort that goes into building a modern motor.

We’re also not immune to public transport – especially based on the edge of the capital - but we’re also well aware that the standard of design could be much, much higher than it is.

So, during one late stint in the office editor-in-chief Cropley wondered out loud from the background chat ‘why not propose a design for a new Routemaster?’A ground-up re-think of the bus, which meets modern regulations, is whisperingly eco-friendly but also delivers old-world style and convenience. Call it corporate responsibility; call it Autocar’s positive contribution to improving public transport. But also call it huge fun to bring to life.

When new product proposals are called for, most heads turn my way. And by an extraordinary coincidence, I happened to have on my desk the card of a man I’d met a few years ago at the Royal College of Art graduation show. Alan Ponsford knew in an instant what needed to be done. And this is the result. The Routemaster Olympian.

Autocar's Routemaster RMXL in detail

Capoco’s Routemaster design, dubbed RMXL, is 9840mm long, that’s 800mm longer than the old model. The 6540mm wheelbase is just over 700mm longer and the width up 162mm to 2550mm. Although the new Routemaster’s roof is 275mm lower, the lost interior space is easily recovered because the floor is also much lower.RMXL will carry 48 people on the upper deck — eight more than the original — but will accommodate four fewer passengers downstairs because space has repurposed for wheelchairs and pushchairs.

At 8230kg, it will weigh around 400kg more than the old version — a tribute to the original aluminium spaceframe design.

The RMXL is also built around a massive spaceframe of aluminium extrusions. Normal buses are built around a welded steel frame, but this aluminium cage should be lighter and much stiffer.

The skin of the bus is made from rolled aluminium panels, and the floors are made from bonded honeycomb sandwich sheets, the same material used by modern passenger jets.

The frame and floors will be fixed together mechanically, but the windows will be bonded in place. The engine and air suspension are mounted on stainless steel subframes.

The key difference between this Routemaster and the old model lies in the transmission. The engine is still in the nose, but there’s no mechanical connection between the engine and the rear wheels. Instead the engine powers a generator that charges the batteries, which drive the electric motors on each rear wheel.The removal of the huge gearbox, propshaft and rear differential vastly increases the ground floor space. The RMXL’s floor is flat and sits below the centre line of the wheels.

This improves passenger access, for pedestrians and those with wheelchairs and buggies. The air suspension will also lower the bus so that the floor is level with the kerb. 

Looked at objectively, one of the most environmentally-unfriendly ways of providing public transport has to be strapping a large diesel engine into a heavy vehicle and then stopping and starting it between five and seven times per mile. The result is that buses can be very ‘dirty’.

While CO2 has become synonymous with ‘pollution’, it‘s Nitrogen Oxides and particulates from inner-cirty diesels that affect human health. Although particulate traps can help, high exhaust temperatures are required to completely burn the soot away, something that can’t be achieved in stop-start traffic. Reducing NoX requires complex in-vehicle treatment, such as the systems used by Mercedes’ Bluetec diesel engines.

Many global cities (including Tokyo, Hong Kong and Delhi) have already addressed this problem by shifting to buses and taxis powered by clean-burning liquid petroleum gas, or compressed natural gas.

However, the next step is to use a hybrid transmission. The RMXL design uses a Ford 2.3-litre ‘hydrogenised’ petrol engine, developing 127bhp. (Boeing is using this engine in a pilotless drone aircraft). Hydrogen fuel is stored in an filament-wound tank, mounted under the staircase.

The engine is designed to run continuously at an optimum speed, driving a 97Kw generator. This charges the Lithium Ion batteries, which are mounted in front of the rear axle. The batteries drive the electric motors on the rear axle.

At a stroke, problems with pavement-side pollution are eliminated and the bus will run quietly – noise pollution is another major problem with heavy buses – and with zero local pollution. A fuel cell stack could be used in place of the engine, but would cost many hundreds of thousands extra.

A simpler, more near-term, solution would be to use a Californian-spec diesel engine running on second-generation bio-diesel. Large-scale storage hydrogen in city and town centre bus stations might not prove popular with local residents. Bio-diesel storage would prove less controversial.

Interestingly, Alan Ponsford points out that there will never be a large plug-in hybrid bus fleet. Typically a bus needs to be cleaned and re-fuelled in three minutes. Re-fuelling with liquid energy is very rapid and efficient. By contrast, if you had to re-charge London’s 8000-strong bus fleet overnight, it might require 20 medium-size power stations running for five hours, to manage it.