Road Rail Vehicles

The Cambridge Guided Busway website carries a list of advantages that a
guided bus-way would have over a conventional railway.

It states that an important advantage is the flexibility for buses to
run both on the guided bus-way and to be able to use conventional roads
where there is no bus-way available, whereas a train can only run from
one railway station to another.

Of course, in Cambridge's case, it's this flexibility that makes the
scheme so hopeless because the guided bit will be where it's least
needed, in the sticks, and absent where it's most needed, in the city
centre. But, in any case, it's not true that railway vehicles cannot be
designed to also run on roads as it has certainly been done in the
past.

So, why is more not being done on this?

Surely, a better solution for Cambridge would be road going buses
capable of also running on rails, that way they could enjoy segregation
right into the city centre whilst retaining the flexibility also being
road going.

Road/rail buses could exploit the flexibility of road transport whilst
also being able to take advantage of the greater speeds, comfort,
safety and accessibility (to city centres) of running on rails.

Branch lines such as the Barnstaple line could at the extremes have
through workings to places such as Ilfracombe (no longer rail
connected) and imagine the Whitby train being able to continue to
Scarborough on the road.

There's also no reason why the buses couldn't be connected together
whilst running on the rails more like a conventional train. Here in
Birmingham, we already have Bendy Buses so the concept of connecting
buses together on roads also exists.

I feel sure this could improve the viability of many branch lines by
improving access and catchment of the railway, able to serve places
near to, but not on, the railway whose only public transport is
currently the bus.

On Sat, 17 Jun 2006 16:11:16 +0100, allan tracy wrote
(in message <1150557076.713585.165910@p79g2000cwp. .com>):

> Of course, in Cambridge's case, it's this flexibility that makes the
> scheme so hopeless because the guided bit will be where it's least
> needed, in the sticks, and absent where it's most needed, in the city
> centre. But, in any case, it's not true that railway vehicles cannot be
> designed to also run on roads as it has certainly been done in the
> past.

I suspect the answer lies in cost.

To make a vehicle that is good for rail AND good for road means a fair bit of
engineering. The majority of dual-use vehicles are I suspect like the
maintenance vehicles I've seen where they still run on the road tyres for
traction and some weight support, with relatively lightweight rail wheels for
guidance. I believe these have quite significant speed restrictions which I
would expect to be because of their limited handling characteristics as a
rail vehicle.

So I think to make road/rail bus you would end up with something that was
very expensive, not brilliant as a rail vehicle (says I thinking of the
appaling ride on some of the non-bogied dmus I've been on), and even worse as
a road vehicle with all the weight of the rail gear to drag around.

By contrast, to make a standard bus or coach into a guided one is relatively
simple - you just stick a couple of guide wheels on and link them to the
steering*. Lightweight, doesn't affect the ride quality from the existing
wheels/tyres/suspension, and I suspect the trackway is relatively cheap to
build as well.

* OK, a little more, but that's the jist of it.