Copyright Ian Wild

Potteries Motor Traction
1956
Daimler CVG6
Northern Counties L31/28RD

The above vehicle is one of a 30 strong batch delivered in 1956 – half with Metro Cammell H61RD bodies, the other half as shown.
These were delivered with Gardner 5LW engines and Twyflex Centrifugal Clutches (rather than the more usual fluid flywheels). Both features I suspect were down to the BET Group’s parsimony in relation to fuel consumption. The 5LW was never a match for the hilly Potteries area in these buses. Over the years, more than half were fitted with 6LW engines and one, H6656, even acquired a fluid flywheel as well. They were colloquially known as ‘Jumpers’ referring to their tendency to lurch when pulling away on an uphill gradient, something more common with the 5LW versions. Only three of the lowbridge variety kept 5LWs to the bitter end, L6664, L6666 and L6673. The photo was taken at Sandbach in May 1969 and shows Burslem (locally pronounced "Boslum") Depots L6676 on a Market Day extra from Hanley. Sandbach market was a popular attraction in the area in those days.

Photograph and Copy contributed by Ian Wild

A full list of Daimler codes can be seen here.

28/03/11 – 10:30

Apparently the Twiflex centrifugal clutch is still in production. To have lasted at least 54 years it must now be a judder-free product, though I know these things often depend on the installation. Fluid flywheels are reckoned to be only 96-97.5% efficient even at high revs/low load (where the engine itself isn’t particularly efficient) so I guess that allowing also for time spent in gear at traffic lights, with the engine on "heavy" idle churning the fluid round, the fuel consumption would be about 8% greater than that achieved with a clutch, whether plain or centrifugal. Two question, therefore:
1) Has anyone any comparative consumption figures?
2) Have any Twiflex-equipped buses survived?

Ian Thompson

25/01/13 – 18:10

There can’t have been many 27ft long lowbridge double deckers built with a top deck capacity of 31. It must have been achieved by an additional 4 seater row – I travelled on these quite frequently on the 46 to Blurton Estates but I don’t recall any particular problem with passing other seated passengers when alighting.

Ian Wild

26/01/13 – 06:38

Here’s a photo of a Twiflex Centrifugal Clutch, looking much like the shoe part of a drum brake, certainly simpler than a fluid flywheel. See //tinyurl.com

Chris Hebbron

27/01/13 – 07:55

That’s pretty much as I recall the Twiflex clutch except that the modern version seems to be hydraulically actuated (pipe to each segment). My recollection is that the shoe assemblies were on metalastic mounts which dampened the centrifugal force as the assembly was accelerated. It’s a long time ago-I may not have this quite right. interesting to see the design is now of Ukranian manufacture! I don’t recall having to replace one of these clutches whereas the fluid flywheel glands in Atlantean, Fleetline and Roadliner were commonplace failures.

Ian Wild

27/01/13 – 12:17

And to what vehicles do you recall these clutches being fitted, Ian?

Chris Hebbron

28/01/13 – 17:35

Chris-all 30 of the PMT Daimler CVG5s of 1956 were delivered with Twiflex clutches in place of fluid flywheels. I’m sure I’ve read somewhere (maybe elsewhere on this site?) that Walsall Corporation also tried them in the mid 50s.

Ian Wild

22/07/14 – 06:48

Walsall Corporation took delivery of 15 Daimler CVG6 buses with twiflex system transmission in 1956 and they were nicknamed "jumping jacks". Here’s a newspaper report from 1974 referring to these buses: www.flickr.com/photos/walsall1955/

Walsall1955

09/12/15 – 06:09

At Stoke Depot we did meal break duties on these on the 46 Blurton run. These ‘Jumping Jacks’ were hated to a man.

David Knight

Copyright Ian Wild

Potteries Motor Traction
1969
Daimler Roadliner SRP8
Plaxton B46D

130 was the first of the final batch of ten Roadliners (130-139) to be delivered to PMT. They had Plaxton bodies to their standard timber framed design with BET style front and rear screens. Apart from the Perkins V8.510 engine, they were similar mechanically to the previous deliveries although they had the miniature Westinghouse air gear shift with a sixth position to operate the centre doors. The Perkins engine was a vast improvement on the Cummins V6 but did suffer from premature cylinder bore wear causing high oil consumption possibly due to some inadequacy in the air filtration system.
The bodies were built with a higher floor level requiring an entrance step (earlier buses had a step free entrance). They were built to the dual door layout then briefly in vogue. Heated windscreens were an innovation on these buses controlled by a wind up clockwork timer(!!) which quickly proved unsuitable for heavy duty bus operation. Some early deliveries went to Stafford Garage and I recall a report from the Inspector there about the indelicacy of young mini skirted mothers when retrieving their push chairs from the luggage pen which had rather a high rail round it!! 130 was the only one in the batch to have the once standard cream panel above the saloon windows, 131 onwards had all red roofs. These were also the first new buses not to have the familiar prefix letters to the fleet number (following on from SN1129 which was the last of the short Marshall bodied Leopards delivered the previous year). The above photo was taken on 1st July 1969 shortly after delivery at the weighbridge at Shelton Iron and Steel where we took the first of each batch of new buses for weighing. The driver is Bill Davies who was a Management Trainee at the time.

Copyright Ian Wild

This is a shot of an earlier Roadliner KVT 180E fleet number S1080 being towed into Stoke Central Works shortly after being burnt out at Swynnerton on 25th March 1969 it was rebodied with an identical body to the 130-139 batch returning to service on 1st August 1969.
PMT cancelled a further order for Roadliners and substituted single deck Fleetlines but date wise they are outside the time period of this website.

Photographs and Copy contributed by Ian Wild

10/03/11 – 07:48

I was the first driver to go into service with 138, it was a Saturday afternoon I was based at Newcastle garage and both 138 and 139 were put on the Burslem Silverdale service on the shift change over. I don’t remember driving anything so fast and it was a struggle not to run early on this service, going up hills was not a problem at all with these vehicles it was "just like driving a mail train as they say"

Michael Crofts

28/07/11 – 15:27

Funny you should mention 138; I’m sure that was the one I saw at Preston North End’s Deepdale ground in the late 1970s having gone there to watch Port Vale play. Only the driver of our Bostock’s coach, who was as big a bus nut as I was, and myself made any comment. It had been sold by PMT to a local independent.

Mel Harwood

22/05/12 – 07:54

I would imagine that it was 137 you saw in Preston as it was latterly owned by Holmeswood Coaches of Rufford … coincidentally the present owners of Bostocks.

Martyn Hearson

10/05/17 – 07:18

I remember Roadliners that West Riding operated, on a trip from Horbury to Flockton on the Wakefield Huddersfield service I think the service number was 89 or 86 this particular Saturday was entering Flockton the Netherton Midgley side and there is a sharp left hand bend just as we approached the bend round the corner came lorry cutting the corner on our side of the road the driver could only put the bus as near to wall and trees on our side of the road as he could and hope that we missed each other which we did ,from the front of the bus came a substantial number of choice Yorkshire adjectives expressing the doubt that our West Riding had of the driver of the lorrys parentage and when we got to Flockton the driver removed the assorted foliage from front nearside wingmirror mounting and doors and nearside open windows, as we got off in Flockton our driver said to my mum are you an lad or rite lass, mum said yes the driver said aye lass that were close at least I haven’t scratched it they only got this b***** yesterday!

David Parkin

03/03/20 – 06:53

From a laymans point of view and having travelled many times on these buses I always thought they offered a much better ride than the previously delivered Roadliners. Travelling on the early batches of Roadliners was much more of a bouncy ride, so was there a change to the suspension on the last batch?

Leekensian

12/03/20 – 06:05

No, the final batch had Metalastik Toggle Link suspension units the same as the previous Roadliners. Thinking about it, I recall a better ride-maybe different rated shock absorbers?

Ian Wild

18/03/20 – 06:49

I recall that two of the original batches of Roadliners were converted to Perkins engines – S1065 & S1078 spring to mind, but did not prevent their early withdrawal along with the majority of the Roadliners.

Leekensian

   Copyright Michael Crofts

Potteries Motor Traction
1961
Leyland Atlantean PDR1
Weymann L39/33F

This is one of a batch of 105 Atlanteans delivered between 1959/1961 and the above picture was taken at the water point at the PMT Newcastle under Lyme depot. It was very rare for this type of vehicle to do the Leek route as it was normally worked by Leyland Titan PD3’s and this bus would normally be on the Longton Newcastle Estates route. So it was a pleasure for me and a first to go to Leek in an Atlantean as I liked driving these splendid vehicles unlike the Daimler Fleetline which I detested. The prefix L in front of the fleet number denotes a low height body which was one of the reasons why this type of bus was normally on the Longton service as there was a low railway bridge in Longton.
During the Potteries annual holidays double deck vehicles would be used on the express service’s to Morecambe and Blackpool, the buses would be either Atlanteans or Fleetlines with Alexander bodies the latter being hard work with their hydraulic throttles and having a top speed of 42 mph, the Atlanteans on the other hand would do between 52-55mph.

Photograph and Copy contributed by Michael Crofts

22/02/11 – 10:06

Thanks, Michael, for this interesting picture of another early BET company Atlantean. As you say, they could really motor, but they didn’t half drink the diesel when doing so. That was just one of the reasons why some operators changed to Fleetlines; lower overall maintenance costs was another.

Roy Burke

22/02/11 – 19:54

Good to see this photo of what was the most common type of bus in the PMT fleet in my time working there. Longton Depot had some of the earliest batch and achieved phenomenal engine mileages of 400,000+ between failures. Frank Ling was the Depot Engineer there and maintained a very high standard of maintenance. My first winter there was a cold one and the Atlanteans frequently failed with the air system unloader valve frozen causing the vehicle to lose all air pressure and hence drive. The unloader valve was mounted under the cab in one of the coldest locations on the vehicle. A rag on a steel bar, dipped in diesel and set alight was the quickest means of unfreezing the unloader and restoring normal operation. Flywheel gland failures were another problem coating the engine bay in oil with the consequent fire risk (wiring fires in the Atlantean engine bays were not uncommon not aided by the wiring insulation becoming brittle with age and falling off). Quite a number of Atlanteans had to be rewired, some being dealt with by local Contractors as the level of work exceeded the available labour in Central Works at Stoke. Leyland tried adding a fan bolted to the fluid flywheel (more correctly the fluid-friction clutch) on a number of buses but there was no real improvement. As originally built, the chassis had rear light units fitted on the rear sub frame and which shone through holes in the fibreglass engine cover. PMT later fitted high level rear lights in the rear ‘tween decks panels thus eliminating the wiring to the sub frame lights located as they were in a very oily environment. The main rear lights were fitted to the lift up rear engine cover and the additional lights were necessary to provide rear lights at night if it were necessary to open the engine cover whilst on the road at night. Oh happy days!!

Ian Wild

22/02/11 – 19:55

The early Atlantean in low height form was a modified lowbridge bus in reality on the other hand the Fleetline with its drop centre rear axle was a true lowheight vehicle from the off It took Leyland until 1966 (four years after the first Fleetlines entered service) before they offered a low height chassis which removed the low bridge layout from the top deck. Having said this the Atlantean PDR1/2 was not one of Leylands finest although when it appeared the AN68 was what the Atlantean should have been from the off

Chris Hough

26/01/13 – 06:24

The seating in the forward part of the upper upper deck on these buses was too low in relation to the window line whilst the rear rows of 4 were too high! This is except the initial row of 4 which were mounted straight onto the raised rear platform resulting in an excellent match between seat height and window level.

Ian Wild