On Fri, 18 Jun 2004 18:34:29 +0000 (UTC), "Terry Harper"
wrote:

"Clive" wrote in message
...

Slight change of subject. As an ex-bus driver in Bristol where our
double deckers had crash boxes, I remember a trip to London and on
travelling on an RM got the impression they had pre-selector boxes.
Can any confirm or deny this? Does anyone out there know how they
worked or have a link to which I could go to, to find out? Thanks for
any sensible answers.

Traditionally, LT used Wilson preselector gearboxes for their STL and RT
buses.

http://www.routemaster.org.uk/ gives a link to a history
http://www.routemaster50.org.uk/rtmaster/history.shtml of the RM, which used
a semi-automatic gearbox initially, I believe, but like the engines, these
have been replaced with more modern units over the years.

From personal observation as a passenger - mostly on the 19 - a
majority of Routemasters still have the original type of gearbox.
This is an automatic, but left to its own devices seems set for rather
relaxed driving, and in particular always starts in second gear.
First gear (out of four) is only available if selected manually. In
practice most drivers seem to use these in semi-automatic mode. The
gear selector in these works in an 'H' gate, much like a manual
gearbox.

My understanding is that the Routemasters used in the former country
area were originally semi-automatic (so the driver had to change gear,
but there was no clutch pedal), and that this was mechanically the
same gearbox as used in the other buses, but without the automatic
control fitted. But this could be completely wrong...

The more recently refurbished/re-engined Routemasters do have new
automatic transmissions, and there are at least two types: one which
has a box with push-buttons and some sort of LED indicator mounted
under the steering wheel, and one which has a floor mounted selector.

Preselector gearboxes were a feature of earlier London buses, like the
RTs, and as a child sitting behind the driver of RTs and RFs I was
fascinated by their working. The principle was simple: the driver
could move the gear lever between different gears at will, and would
then press a pedal - where you'd expect to find a clutch pedal - which
would put the bus into whichever gear he'd selected.

So he'd put the gear lever into first while the bus was stationary,
then press the pedal when he was ready to move. As he moved off, he'd
put the gear lever into second, then use the pedal to change up when
he was ready. Then he'd move the gear lever into third, and then
change up with the pedal, and so on.

I've occasionally wondered, in retrospect, and maybe somebody reading
this knows: did reverse work the same way on preselective gearboxes?
The thought of travelling forward, forgetting that you'd preselected
reverse, and accidentally touching the operating pedal, is fairly
frightening.

Presumably part of the idea was to ensure that, before power steering,
and also in days when hand signals were important, the driver could
arrange to have both hands free at tricky moments.

Incidentally, thinking of technology that's changed on Routemasters
over the years, I'm intrigued by the conductors' new ticket machines
with Oyster readers. There appear to be two completely separate
units: is the unit attached to the conductor's belt purely a printer,
controlled from the red unit with the Oyster reader? And how do the
two units communicate? Infrared? Bluetooth? Some sort of
proprietary radio system? Teleportation?

In any case it looks as though a lot of work has gone into design and
manufacturing of these machines. If I didn't know better I'd see this
as a sign that conductor operation was here to stay on a large
scale...

Martin