Home page Up
Canvey Engineering - Articles - Bus for London
Copyright CRAMEC membership no 231
In 2008 Boris Johnson announced the replacement of the old Routemaster bus. A competition was held for the design of a new bus; this was to be called a New Bus for London. A set of specifications were announced for the new bus; these stated the bus was to be two-man operated, have access for the disabled and a jump-on-and-off platform at the rear. For those of you that have seen the original specification and have also seen the bus that is now the so-called New Bus for London, or the New Routemaster as it is officially known, you will notice that the specification does not match the new bus. So for this reason we ask you, when viewing this proposed bus scheme, to consider this in mind.
A member of this club entered the competition with a bus like no other seen before. The strange wheel arrangement is to support a segmented pantograph at the top of the bus that picks up its supply from overhead power lines. These power supply lines do not have to be over the entire length of the journey, as the pantograph is able to detect the presence of the power lines and raise itself to engage the power to charge the onboard batteries that power the bus. This means that, at junctions, you do not have the complexity of overhead wires that you use to have with trolleybuses and trams. The pantograph detects the oncoming junction and lowers itself allowing the bus to run on batteries.
As you would expect with any electric vehicle, it has regenerative braking, which is achieved by charging a series of high-capacity capacitors. This saves battery life and is also more efficient. The batteries and the capacitors are inserted into the bus, through the side between the wheels, and are all connected to a common power supply system. So depending on the route chosen for the bus, and the availability of overhead power, these interchangeable power pods can be reconfigured for the best use of the route chosen. As these power pods are inserted into the side of the bus they can quickly be changed to either reconfigure the bus or change a defective power pod. In the event that the bus has to travel a long distance without overhead power there is a diesel generator under the staircase. To achieve the weight distribution for the batteries and the bus, the bus has a side chassis and a central structural member under the floor.
One problem with disabled people is it is often difficult for a bus driver to determine whether they need assistance getting on and off the bus. You will notice the disabled persons ramp at the front of the bus is actually part of the door that is deployed every time the front door is opened.
The jump-on-and-off platform at the rear of the bus has a gate across the exit; this gate is open when the bus is at a bus stop and closed when the bus is travelling. However when the gate is in the closed position, it can be pulled backwards into the bus allowing people to get on and off the bus when not a bus stop.
Looking at the front of the bus, you will notice that the left-hand side is curved towards the disabled access. This curvature has a specific function and is used when pedestrians step off the kerb in front of the bus. On a flat fronted bus when a pedestrian is hit the pedestrian is knocked forwards, falls to the floor, and then goes under the bus. The curved front of the bus prevents this; instead it spins the pedestrian and throws them back onto the pavement. (To be continued)
Copyright CRAMEC membership no 231
Home page Up Top