Routemaster Buses

[Hopkirk]

Did Routemasters have automatic or manual gearboxes?

[boxtops]

Says here that it's fully automatic. http://www.icons.org....gning-the-routemaster

[cupid04]

built with automatic / semi automatic gear boxes.

[sanden]

I am reliably informed they are semi automatic but can be switched to fully automati

[Buenchico]

Why the past tense, Hopkirk?

Routemasters are back!
http://www.bbc.co.uk/news/business-11746769

Chris

[mike11111]

Oh, the joys of rear entry buses where you could hop on and off at will, despite the protestations of the conductor. One of our childood joys was to wait by a junction till a trolleybus came by, then pull the handle on the post to change the points to the wrong direction in which the bus was going so it would come to a halt and the conductor would have to extract the long pole from under the bus and reattach the trolleys to the wires.

[sanden]

Chris - Surely you mean the new fandangled version of the proper routemaster.
Sandy

[Hopkirk]

Thanks all.

Does a semi automatic have a clutch?

[Hopkirk]

Clutch pedal, I mean.

[craft1948]

My car is semi or fully automatic.....no clutch.

[sherrardk]

I am curious as to why you would like to know.

[NazNomad]

Semi-Automatic in a bus is really 'pre-select'

From Wiki ... A preselector gearbox is a type of manual gearbox used on a variety of vehicles, most commonly in the 1930s. The defining characteristic of a preselector gearbox is that the manual shift lever is used to "pre-select" the next gear to be used, then a separate control (a foot pedal) is used to engage this in one single operation, without needing to work a manual clutch.

I remember driving an old Armstrong with a pre-select box ... v-weird, lol

[Buenchico]

Definitely just the two pedals:
http://www.arca-bus.o...ml2361_cab_a_gran.jpg

[Hopkirk]

I'm just intrigued.

I didn't think they were up to making automatic gearboxes in the fifties, but a manual gearbox on one of those would really be hard work.

Also I don't really know what a semi automatic gearbox does. Is it the clutch or the gear selection which is done automatically?

[Hopkirk]

Oops, took too long typing so the answers came before the questions.

[New Judge]

No, Routemasters do not have pre-select gearboxes. The last London buses to have them were the RT/RTL/RTW range of double deckers, the RLH low bridge double decker, and the RF single deckers. Older readers will also recall the Daimler ambulances seen in London and elsewhere which were similarly fitted.

Routemasters have four-speed epicyclic gearboxes and only two pedals. Selecting 4th gear position means the bus is in full automatic mode and can simply be driven from standstill to full speed. The bus will start off in second gear and will automatically change up to 4th as speed increases.

The automatic function can be overridden by selecting a lower gear, in which the bus will remain until changed manually.

Some variants (mainly those used on Green Line services) had the automatic function disabled and had to be driven manually through the gears.

I own a part share in a Routemaster and used to own an RF.

[Hopkirk]

Thanks Judge.

Great to get an answer from an expert.

[New Judge]

Just a bit more info on automatic gearboxes in general, Hopkirk, which may be of interest.

Experiments with automatic transmission began almost as soon as petrol driven vehicles were first seen but it was not until the late 1930s that a reasonably practical version was available. By the early 1950s most cars in the US were being offered with automatic transmission as standard.

By the time the Routemaster was being designed (development began in 1947 and the first prototype was delivered in 1956) the technology was well advanced. Although Leyland provided two of the four prototypes, AEC were the principle development partners with London Transport and they developed the fully automatic gearbox I described in my earlier answer. They did this in association with a company called Self Changing Gears Ltd, who until then had specialised in pre-select gearboxes.

Semi automatic gearboxes differ from automatic ones in that they need an input from the driver to change gear. They still have an automatic clutch, so no engagement/disengagement action is needed from the driver. Most automatic vehicles (including the Routemaster) have a semi-automatic function. As I described, selecting a gear other than 4th will see the bus remain in that gear until a manual change is made. Although having only two pedals, current Formula One cars have a true semi-automatic gearbox and no gear changes occur without the driver’s action.

In the earliest days of my interest in buses London Transport still operated some pre-war Leyland “TD” single deckers:

http://www.skylineaviation.co.uk/buses/TD.html

These had manual “crash” gearboxes with no synchromesh. Double de-clutching (i.e. lifting the clutch pedal up and down as the gearstick moved thro

[New Judge]

[It seems AB just chops your answer down now instead of telling you it's too long]

These had manual “crash” gearboxes with no synchromesh. Double de-clutching (i.e. lifting the clutch pedal up and down as the gearstick moved through neutral) was necessary. They were a handful and getting a fully laden one of them on route 236 moving from the bus-stop on the hill near the old Arsenal stadium was a skill few drivers mastered. It demonstrated what “clutch judder” really was!!

[Hopkirk]

They don't know they're born today.

[New Judge]

In fact, upon reflection, F1 cars perhaps do not quite fit the bill of “semi-automatic” as they have a manual (hand operated) clutch. However, this is only necessary for pulling away from standstill and is not needed for gearchanges.

However, I digress!