AEC Noticeboards The AEC NOTICEBOARDS
ADVERTS • PHOTOS • DISCUSSION
Celebrating the products of AEC Southall Ltd, most famous as builder of London's buses.

It is currently Sun Nov 19, 2017 4:18 pm

All times are UTC




Post new topic Reply to topic  [ 25 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
PostPosted: Mon Jan 27, 2014 12:14 pm 
Offline

Joined: Tue Jan 24, 2012 4:44 pm
Posts: 169
Dear 9711T,
Thanks for the follow up.
Guy certainly had a better idea of what municipals and others in the home market wanted in a single decker than Daimler. To be fair to them, the Arab UF/LUF was absolutely orthodox with most parts interchangeable with its double deck namesake of the time (Save a rare few half-cab Arabs with Lockheed CFS Brakes or Meadows 6DC630 engines). Daimler had instead decided to do an underfloor engined version of its CD650, which in its 26ft version sold a grand total of a dozen in the UK. (Six to hilly Halifax, four (two batches of two) to Daimler-loyalist independent Tailby & George (Blue Bus Services) between Derby and Burton upon Trent, one to Glasgow Corporation Transport and one to Tumilty of Ayr (almost as exclusively-Daimler as BBS) for its share of the AA Motor Service plus a demonstrator: there were then two further 30ft versions coded CVD650-30 in the late 1950s, one to Glasgow and the other a show chassis which was eventually snapped up by a Doncaster area independent.) Not only was the CD650 too powerful for the majority of home market operators when launched, the CD650 and Freeline had a very complex hydraulic system, working brakes, steering and gearbox actuation (more on those Lockheed CFS brakes later).

You are scathing about vacuum brakes but with relatively slow road speeds (a 20mph maximum for all but lightweight PSVs until the early 1950s) and restrictive vehicle dimensions (26ft double deckers until 1950-51, 27ft 6in for single deckers, with 8ft width only on specially approved routes from 1948 and 7ft 6in a common width option in some areas well into the 1960s and available on the Leopard until the late 1970s as a special order and on the Bristol LH and LHS (the track on these, like the Albion Viking and Bathgate Leyland Cub was narrow regardless of coachwork) until the model was discontinued) they were at least a known quantity, air brakes had had a particularly disastrous debut in the UK bus industry in the Karrier WL6 and DD6 6x4 chassis in the 1926-9 period although Guy, Karrier (by then under Rootes Group ownership, assembling the better Huddersfield-originated designs –read trolleybuses, refuse wagons and the Karrier Cob mechanical-horse– at Luton) Sunbeam (which from 1931 when their first trolleybus appeared to 1934 was linked with Talbot–Darracq (UK) then bankrupt , then from 1936 part of Rootes, sold to Brockhouse in 1946 and then to Guy in 1950) Leyland and AEC managed to sell air-braked Trolleybuses. During the 1930s vacuum-over-hydraulic systems were almost as popular as the triple servo. TD5/6c and 7 Titans, Birmingham’s 900 or so Daimler COG5s and most of London’s 1937-9 STLs being examples but triple servo became normative in wartime and all three utility double deckers (the Arab, CWA6 and Bristol K) had it; as had early post war introductions such as AECs so-called Regent II (the O661/20) and the home market Crossley, it was standard also on the Albion Venturer and the Leyland Titan PD1. Very few PD1s had air brakes and Leyland were courageous to make it optional on an exclusively home market bus so early, from 1946. I believe the only air-braked Venturers were the 30 footers exported to South African Railways. Incidentally, the Arab UF achieved most of its export sales in Southern Africa and the Benelux countries, although Spanish independents and municipals were also keen buyers.

London was a pioneer for motorbuses in going back to air brakes in 1938 (RT1), perhaps the(separately-managed) Tram and Trolleybus branch influenced the bus division for this prototype, of course the Underground always had the prestige within LPTB and it might have been their thinking that air-brakes were the done thing. The 2RT version of the Regent O661 delivered late 1939/early 1940 suffered a slew of problems with its air-pressure system on introduction. People who study LT in much more depth than I do say that had it not been for wartime and the need to keep its newest buses running with no alternatives available (bus production was frozen on Government order shortly after RT151 was delivered) LT might have backtracked. Glasgow also kept its example (the only ‘pre-war’ RT out of London) going. As it was the Regent III was first made generally available from December 1946 in pure London form, with the low bonnet, air-pressure brakes and air-actuated pre-selector gearbox. Air brakes were standard on preselector ‘provincial’ Regent IIIs but an option on layshaft-gearbox variants. When the Titan PD2 came on-stream most operators still preferred triple servo-vacuum. It was, though, some engineers in the municipal sector who pioneered the air-brake PD2 and took air-braked synchromesh Regents. Blackpool, whose 1930s English Electric streamline trams (which renewed most of its fleet and some still ran until its low-floor conversion recently) had air-pressure wheel and track brakes took all of its post war Titans (from 1950) so fitted. Bolton was another pioneer, it took air brakes on its PD1s and the only double decker not so fitted afterwards was a stock PD2/12 bought for a short-notice requirement in 1956, and not surprisingly Sheffield: as Romans might think of it the other city of seven hills. Halifax also took air-braked Regents at this time.

Topography was an important factor, but not a ruling one. Other factors to be borne in mind were engineering culture and climate. The major source of practical engineering education in the UK in the period was the railways, through their apprenticeship systems, and vacuum brakes were overwhelmingly the norm on British railways (and indeed British Railways) until well after the Beeching era, at the time of the Arab UF’s introduction only high-frequency commuter lines such as the Southern 3rd-Rail electric system, counterparts in large north of England cities such as Liverpool and Newcastle, London Underground and some steam-hauled LNER commuter services out of King’s Cross and Liverpool Street and equivalent LMS/LNER Glasgow suburban systems used air-pressure braking. The redoubtable Geoffrey Hillditch was not the only Chief Engineer nor General Manager of a UK bus operator to have served his time with the railways.

The British Isles can also get very cold in winter and as Mr Hillditch attests in his books Looking At Buses and A Further Look At Buses, this caused early-1950s air pressure braking systems to fail when the climate fell below zero Celsius for a while, albeit fail safe unlike some of the Clayton Engineeering Company’s Karrier products of the 1920s. He recalls his maintenance staff at Halifax having to apply blow-lamps to air lines to get brakes off in some hard winters; later systems –such as the one he specified for the Dennis Dominator– incorporate air-dryers.

Of course the original CD650 and all Freelines built until around 1954 had a different braking system, this was the Automotive Products Lockheed continuous-flow hydraulic braking system, major UK user being Birmingham and Midland Motor Omnibus Company (Midland Red) who used it on all of its own-build buses from 1946-69. As well as some inconvenient and expensive maintenance needs (from Mr Hillditch’s point of view when he had six to look after) it required type-trained drivers to work correctly in service and Peter Hendy, the London Assembly’s Transport Commissioner (the senior executive in Transport for London) recalls the BMMO D9 integral double decker he drove so equipped as “that blxxxy bus with no brakes”.

Conversely to these UK facts I understand that the Auckland Transport Board renewed its fleet from 1951 on the basis of 33ft long 8ft 6in wide dual-door single deckers, electrically or diesel powered. May I say that the use of Compression-Ignition engines was quite avant-garde for your country in that decade? At those dimensions it is perhaps not a surprise that the Leyland and AEC vehicles, which were both drawn up initially at 27ft 6in by 7ft 6in and whose engines developed 125 bhp were not considered powerful enough for Auckland’s challenging topography; as your handle on this site is related to the electrically powered vehicles Auckland took can you enlighten us as to the power of their motors and perhaps the maker of this vital component and also perhaps the control-gear?

As I understand it the people building electrical motors for trolleybuses at the time were Crompton-Parkinson, English Electric, GEC and Metropolitan-Vickers, the highest continuous-output offered in the UK by all four of them was 125bhp. This was considered more than adequate by LT for its famous Q-class BUT 9631Ts.

Braking systems for Auckland: The Regal IVs and Royal Tigers had air-pressure systems, did the BUT 9711Ts also have regenerative braking? This was patented by Stanley Guy, William Rees and the Rees-Stevens partnership in 1926, so was out of patent by the middle of the war. I know some of Nottingham’s Sunbeam and BUT trolleybuses had this by 1948.
The earliest Auckland Freelines must have had the CFS hydraulic brakes, did the later batches and were the drivers specifically-trained in the idiosyncrasies of its operation? (Halifax drivers and probably all of those in these islands not trained by Midland Red found it problematic: CF Peter Hendy earlier.) Glasgow’s one Freeline and its 26ft CD650 were both scrapped at seven years old, the body from the CD650 going onto a similarly-aged CVD6. FYS999 the CVD650-30 (Glasgow’s only rear-entrance 30ft motorbus) had air-pressure brakes but lost its power steering, air-servo to the gearbox and Daimler engine on successive overhauls. It was known to Glasgow bus drivers as ‘the bomber’ when originally-powered on account of its over-performance in Glasgow. It is running as part of the Glasgow Vintage Vehicle Trust collection in its out-of-service mechanical condition, with the air-system only serving the brakes and a 120bhp Gardner 6LW powering it rather than the 150bhp CD650 it was new with. I have ridden upon it so-preserved and it is slightly less ponderous than the shorter but similarly bodied PD2/24 Titans in GVVT care, that said FYS999 and the FYS and SGD Titans can keep up with current Glasgow traffic on a Sunday in October, unlike the utility Guy Arab 5LW reconstructed at the Scottish Vintage Bus Museum, Lathalmond. Sitting behind the driver on my rides in it, it has always felt marginal for power, the original twin-plate clutch and sliding-mesh gearbox with back-to-front shift pattern must have further deterred drivers.

Incidentally all British United Traction trolleybuses from its 1946 formation until 1953 were built at the Ham, near Kingston upon Thames, Surrey, factory Leyland established in 1918 to recondition RAF type lorries reclaimed from the War Department, in the 1930s this factory built the original Leyland Cub. The 9711T is particularly unusual as an export single decker built to AEC rather than Leyland design (may I ask its namesake if it has a frame cranked over the axles à-la Regal IV or CRT Worldmaster? I seem to recall the ETB1-3 had a frame straight in elevation like the Royal Tiger and normal Worldmaster. Later Crossley at Stockport built BUT trolleybuses, finishing with 30ft 9614T double deckers and 35ft RETB3 single deckers for Glasgow. Shortly after these were finished, Stanley Markland, works manager at Leyland from 1946 , whose first directorship was with BUT, became chief executive at Albion, replacing Hugh W Fulton the last member of the founding families. The last BUT trolleybuses were built at Leyland, final examples of the LETB3 going to Portuguese municipals in 1964. I think the last Sunbeams went to Iberian operators at around the same time, although if the MF2 had followed the same path as the F4 and F4A, then it would have used a Guy-designed frame and axles.

I notice you think that the ideal Leyland Royal Tiger specification would be air-brakes and an air-actuated AEC preselector transmission. No home market Royal Tigers had this, but Leeds took 30 of the similarly specified PD2/14 Titan in 1954 before moving to the Pneumocyclic PD2 together with semi-auto Daimler CVG6s and AEC Regents. Of course London Transport had 2,111 Titans with the same driveline.

I’d not known of a 170 bhp rating for the Cummins V6 VIM, Roadliner buses were advertised at 150 and coaches at the full 192, PMT at one point de-rated its Cummins-powered buses to 135 and experimented withpedestal-type air-shifts to the transmission to prevent overspeed-events... As for the VINE eight cylinder, as I understand it, only Atkinson used it in the UK in a heavy-hauler called the Omega. The VIM and VINE engines were all imported from Indiana, the NTC straight six, built for Europe in Shotts near Motherwell, Lanarkshire, was considered too big and heavy for most haulage applications although it went into that cult-type, and certainly not a haulage vehicle, the Ministry of Transport 6x6 Atkinson motorway gritter.

Although Sir William Lyons was courted by Cummins to licence-build the VIM and VINE at the former Henry Meadows factory adjacent to Guy Motors, he did not complete on the deal; if he had the VIM and VINE would have been built and sold in the UK as Jaguar-Cummins. He deliberately kept himself informed on Daimler’s (and later Guy’s and Coventry Climax’s) products as he did on Jaguar’s, he is recorded in one of his biographies as being distressed by the shortcomings of 6000EH, the prototype Roadliner bus, and the Cummins V6 Fleetline (one guesses 7000HP) placed with Sunderland.

A business history of Rolls-Royce records that Sir William approached them for a lightweight V8 turbo diesel (Ford being in and then out of the action but BMC approving Jaguar’s approach) and an example using a Silver-Shadow block bored to 6.57 litres with a beefed up bottom end was on bench-test at Wolverhampton when BLMC happened.
Krupp, with a West German built haulage range, but one dependent on Deutz, MAN or Daimler-Benz engines, did sign such a deal with Cummins by 1964, and within three years they were out of the market. The last of their steel cabs went on LHD Atkinsons.

Also the reason for having one factory making epicyclic gearboxes and underslung worm axles is that Lyons was actually rather better at rationalising than Leyland. His plan with the Jaguar and Daimler saloon cars was to rationalise to one model and family of engines, the CVG6 was attracting more orders than the Arab V KMB having a tendency to buy more buses. The bus range was going to be all Daimler except for truck derivatives, with these badged Guy where that name was better known.

The Chrysler-Cummins VAL and VALE engines built in Darlington were no better than the VIM and VINE, the only PSV to have a VALE was a heavily modified Ford R226, (search Flickr for Whitefriars Ford Cummins) shortly after Chrysler getting control of Rootes, Perkins engines (6:354 and V8-510 to start with) went into the K-series Dodge which after a few years effectively replaced the C and V series Commers. Around the end of Roadliner production, after deploying Cummins engineers seconded from Columbus Indiana at Hanley, and allegedly Darlington and Bournemouth (who took 17 replacement VIM engines over 11 buses during the warranty period; the only ex-Bournemouth Roadliner surviving is the one refitted with a Perkins V8-510) Cummins admitted that the VAL and VINE (both designed for stationary generating applications) were not suited to stop-start operation.

The Guy Big J did later use the 500 series headless wonder, particularly in weight-critical applications, notably those mixer and light-artic ones. However from its 1968 announcement the next appearance of the headless wonder I can confirm was at the 1970 Earls Court show in the pre-production examples of the Lynx, Buffalo and Bison lorries, the Leyland National and the Bristol Omnibus Company RE (coded XRELL) on that manufacturer’s stand. The 500 was designed for maximum payload applications, the plan was that with an LMC rationalised Pneumocylic gearbox close-coupled using a charged coupling (and at this time LMC were trying to persuade haulage operators to take the Pneumocylic too, the splitter version going into the Super-Beaver, the Mandator V8 and the Gas Turbine Truck) the 500-series engine plus gearbox would weigh less than 1,000lb (454Kg). I wonder if Christchurch (NZ) had to take the 510 rather than a Gardner or the 680 in its RELLs because of your country’s axle-weight limits. I know that in 1971 or 1972 they took a Swift 505 3MP2R with a body sharing a number of features (front light-clusters and unusual seats among them) with the 1970 National show exhibit. Christchurch were very much an ACV fleet, am I right in saying that all their Regal IVs had Park Royal bodies and some of their Reliances were bodied by Crossley?

You mention a 33ft 6HLW-powered Atkinson in NZ, Sunderland had three of those (46-8: WBR246-8): the last Atkinson PSVs built and they were easily the most powerful single deckers in the fleet at the time, succeeding 1959-61 Reliances in that role. (Previous SCT management had some Arab III single decks with 6LWs but 1953-69 GM Norman Morton put those engines into double-deckers at the soonest opportunity, 5LWs from those going into the single deck Arabs.) Sunderland and Doncaster were the only UK operators who took mid-engined single deckers specifically designed for this intermediate length in the 1960s. (36ft by 8ft 2 1/2in being legalised in 1961 for all buses with effect from 1/1/1962.) They both wished to extend driver-operation and were mindful of the existing national agreement between the Municipal GM’s Committee and the Transport Unions that 45 seated was the maximum capacity allowed for driver-operated single-decks, unless subsequently individually negotiated and agreed. These three Sunderland buses were particularly odd in that they had SCG gearboxes (un-badged Leopard-style Pneumocyclics) but vacuum brakes, thus having both an exhauster (for the brakes) and a compressor (for the gears), both doors were powered from the electrical system. 46 was initially delivered with a David Brown constant–mesh gearbox but even though some of the Reliances were synchromesh and Sunderland’s previous two Atkinsons were front-engined 30 footers with constant-mesh gears powered by 4LW engines (Type L544LW) the driving staff refused to accept it. Of the three UFE Atkinsons for Sunderland, only 47 has not survived and a driveable facsimile of one is available to download for people with the Midtown Madness II driving game... Marshall-bodied WBR246-8 were also the first examples of the definitive BET style with peaks and double-curvature glazing at front and rear not built to maximum length, being registered between December 1963 and February 1964. Doncaster took its Charles H Roe bodied Royal Tiger Cubs (also B45D) in two batches, one in 1965 with flat-glass windscreens and on manual-transmission RTC1/1 in 1965, the second batch, Pneumocyclic RTC 1/2 arrived in 1967, and had peaked roofs with the Park Royal-Roe standard at the time of an Alexander windscreen and a BET style rear window. By the time the last of these had arrived, Leyland had decided that the short-wheelbase Leopard L1 and L2 and the Royal Tiger Cub would be rationalised into the PSU4 Leopard, which was much more RTC than L. I have ridden on Sunderland 46 and it is a refined and well put-together bus but with a rather higher floor line than a contemporary Bristol MW or Reliance, although the entry platform is lower than the saloon floor. A couple of years ago, just before he retired, David Dean of Classique (the Paisley-based vintage coach tour operators) showed two of his Leopards at a Glasgow Vintage Vehicle Trust Running day. The 1973 Panorama Elite III-bodied PSU4.4R (SCH40L) carried a Royal Tiger Cub Shield.

The national union-management agreement also explains why instead of the Panther being proposed to it (and most of the other larger Leyland customers) Manchester Corporation asked for a 33ft version. A Panther driveline layout could not accommodate the 600 or 680 to a 33ft length without breaking UK C&U rules on rear overhang. Manchester outright refused Panthers and said to Leyland that they had been briefed on a rival product (the Daimler Roadliner ) and it was available at 33ft. This is the wherefore of the most woeful failure of all post war Leyland Motors or LMC single deckers, the Panther Cub. Sunderland took three of these in 1965 before concluding negotiations with their driving staff and going for a massive re-equipment with 86 Panthers, 25 full-length Swift 505s, ten RELL6G and three Roadliners, all to then maximum length and width, dual door (B47D) and most to Norman Morton’s body design. Less than a year after Sunderland’s first Panther being shown at Earls Court, Manchester (who must also have re-negotiated on the basis of double-deck driver-operation being legalised in 1966) ordered 30, of which 29 were delivered thanks to a fire at Metro-Cammell’s Elmdon works. Both Manchester’s Panthers and Panther Cubs were withdrawn early and seemed to work better in Australia than the UK. As I say in my Wikipedia article about the Panther Cub, at least it provided the frame for the short-wheelbase AEC Swift 505, which between 1966-75 was quite a strong seller on the home market and had some business elsewhere.
With its short Swift 505s and the preceding Swift 691s (which they called Merlins, confusing the Swift 691 with a planned but not built export variant on the Swift /Panther theme, which would have used a Panther coach frame and Regal VI axles) and the 1965/6 experimental Atlanteans, Fleetlines and Reliances, London Transport returned (reluctantly) to air-pressure braking after its Routemasters all used the Lockheed full-power hydraulic system, which by all accounts is much more reassuring to drive than the CFS. The Fleetlines, Metro-Scanias, Metropolitans and Leyland Nationals London took in the 1970s were also air braked, and the Bristol LHS and LH (IIRR) air-over hydraulic, but of course all 16 or so FS Ford Transits vacuum. Thus London made sure that when it got its teeth into Leyland about Project B15, that Hydraulic brakes would be standard. They also persuaded MCW to build all of LTs Metrobuses with these. It is said of generals that they fight the previous war, the same is true of LT with its post-1950 change from air to hydraulic, when from 1985 LT was set to be devolved, downsized and de-regulated (the latter never happening) LT converted all of its Metrobuses to air-brakes and its TN-series Titans to air-over-hydraulic, the double-wishbone front IFS meant the front hub could not fit an air-brake unit, although the Olympian air brake system fitted on the back without a problem.

I did promise you I would re-read the relevant chapters of Doug Jack’s The Leyland Bus Mark 2 with regard to the BLMC export market products from Fallings Park, Wolverhampton. Doug Jack says (pp419 et seq.) ‘The Arab was withdrawn in 1971 and the last Warrior left the factory about three years later.’ He summarises the initial introduction of the Victory, ‘from 1956 initially with Gardner and Leyland horizontal engines… development of the Invincible truck…. most production to Belgium and Holland, with less frequent sales to Spain, Portugal, Greece and South Africa.’ He says the Victory J was introduced from 1969 ‘allowed by an expansion of the Guy Big J truck’: RHD only until 1972, vertical-front Leyland O680 with options of Gardner 6LX and 6LXB, with the rationalised Pneumocyclic or –I surmise Thornycroft– constant-mesh transmission, Guy hub-reduction rear axle, dual-line air brakes and wheelbase options of 18ft or 20ft 6in with entrance ahead of the axle and 21ft for the variant with entrance aft of the front axle. One prototype had a 500 engine. The AEC Ranger and some Clydesdale bus variants were discontinued in 1975 in favour of the Victory J. This gives me an end–date for the Ranger, which before I had puzzled over as the last examples were bodied in Montevideo circa 1978; 1975 makes sense as the Mercury, Marshall and small-engined Swift, together with their 505 engine died in the same year. He does mention the 1975/6 South African double deckers but not the later CMB/KMB and other Hong Kong examples. These, the Victory 2 series II, had Worldmaster CRT, rather than Guy Big J-style frames to reduce overall height, and the vast majority had Voith D851 transmission; all were 6LXB powered and the vast majority had locally assembled Walter Alexander CB-type CKD bodies, the rest similar units supplied by Duple-Metsec. It was a reliable bus but far from a stable one, the Wikipedia article ‘Leyland Victory’ contains a list of all the overturning incidents involving the type. Fallings Park also built most Scammell Crusaders, so if somebody ordered Big J4Ts with R-R Eagle engines and Fuller Roadranger gearboxes and similarly specified Crusaders, did they actualy believe they were dual-sourcing? One customer who took both was of course the state-owned haulge concern BRS, they also took nearly identical Seddon 32-Fours, but they were at least assembled by a different factory and one outside BLMC, although out of mostly the same parts; notably engine, gearbox and cab...

Automotive Products of Birmingham in the UK licenced both the CFS and the later full-power hydraulic braking system from Lockheed Aircraft Corporation of the USA. The founders of that business, now known as Lockheed-Martin, were brothers from a family of Ulster immigrants into the US and their name at birth was spelt Loughead, they decided to re-spell it to US phonetics (or even fonetiks) after too many people called them Log-Head.

Best Wishes

Stephen Allcroft
Cardross
Scotland


Top
 Profile  
 
PostPosted: Mon Jan 27, 2014 7:34 pm 
Offline

Joined: Tue Jan 24, 2012 4:44 pm
Posts: 169
Dear 9711T,

Thanks for the follow up.

Guy certainly had a better idea of what municipals and others in the home market wanted in a single decker than Daimler. To be fair to them, the Arab UF/LUF was absolutely orthodox with most parts interchangeable with its double deck namesake of the time (Save a rare few half-cab Arabs with Lockheed CFS Brakes or Meadows 6DC630 engines). Daimler had instead decided to do an underfloor engined version of its CD650, which in its 26ft version sold a grand total of a dozen in the UK. (Six to hilly Halifax, four (two batches of two) to Daimler-loyalist independent Tailby & George (Blue Bus Services) between Derby and Burton upon Trent, one to Glasgow Corporation Transport and one to Tumilty of Ayr (almost as exclusively-Daimler as BBS) for its share of the AA Motor Service plus a demonstrator: there were then two further 30ft versions coded CVD650-30 in the late 1950s, one to Glasgow and the other a show chassis which was eventually snapped up by a Doncaster area independent.) Not only was the CD650 too powerful for the majority of home market operators when launched, the CD650 and Freeline had a very complex hydraulic system, working brakes, steering and gearbox actuation (more on those Lockheed CFS brakes later).

You are scathing about vacuum brakes but with relatively slow road speeds (a 20mph maximum for all but lightweight PSVs until the early 1950s) and restrictive vehicle dimensions (26ft double deckers until 1950-51, 27ft 6in for single deckers, with 8ft width only on specially approved routes from 1948 and 7ft 6in a common width option in some areas well into the 1960s and available on the Leopard until the late 1970s as a special order and on the Bristol LH and LHS (the track on these, like the Albion Viking and Bathgate Leyland Cub was narrow regardless of coachwork) until the model was discontinued) they were at least a known quantity, air brakes had had a particularly disastrous debut in the UK bus industry in the Karrier WL6 and DD6 6x4 chassis in the 1926-9 period although Guy, Karrier (by then under Rootes Group ownership, assembling the better Huddersfield-originated designs –read trolleybuses, refuse wagons and the Karrier Cob mechanical-horse– at Luton) Sunbeam (which from 1931 when their first trolleybus appeared to 1934 was linked with Talbot–Darracq (UK) then bankrupt , then from 1936 part of Rootes, sold to Brockhouse in 1946 and then to Guy in 1950) Leyland and AEC managed to sell air-braked Trolleybuses. During the 1930s vacuum-over-hydraulic systems were almost as popular as the triple servo. TD5/6c and 7 Titans, Birmingham’s 900 or so Daimler COG5s and most of London’s 1937-9 STLs being examples but triple servo became normative in wartime and all three utility double deckers (the Arab, CWA6 and Bristol K) had it; as had early post war introductions such as AECs so-called Regent II (the O661/20) and the home market Crossley, it was standard also on the Albion Venturer and the Leyland Titan PD1. Very few PD1s had air brakes and Leyland were courageous to make it optional on an exclusively home market bus so early, from 1946. I believe the only air-braked Venturers were the 30 footers exported to South African Railways. Incidentally, the Arab UF achieved most of its export sales in Southern Africa and the Benelux countries, although Spanish independents and municipals were also keen buyers.

London was a pioneer for motorbuses in going back to air brakes in 1938 (RT1), perhaps the(separately-managed) Tram and Trolleybus branch influenced the bus division for this prototype, of course the Underground always had the prestige within LPTB and it might have been their thinking that air-brakes were the done thing. The 2RT version of the Regent O661 delivered late 1939/early 1940 suffered a slew of problems with its air-pressure system on introduction. People who study LT in much more depth than I do say that had it not been for wartime and the need to keep its newest buses running with no alternatives available (bus production was frozen on Government order shortly after RT151 was delivered) LT might have backtracked. Glasgow also kept its example (the only ‘pre-war’ RT out of London) going. As it was the Regent III was first made generally available from December 1946 in pure London form, with the low bonnet, air-pressure brakes and air-actuated pre-selector gearbox. Air brakes were standard on preselector ‘provincial’ Regent IIIs but an option on layshaft-gearbox variants. When the Titan PD2 came on-stream most operators still preferred triple servo-vacuum. It was, though, some engineers in the municipal sector who pioneered the air-brake PD2 and took air-braked synchromesh Regents. Blackpool, whose 1930s English Electric streamline trams (which renewed most of its fleet and some still ran until its low-floor conversion recently) had air-pressure wheel and track brakes took all of its post war Titans (from 1950) so fitted. Bolton was another pioneer, it took air brakes on its PD1s and the only double decker not so fitted afterwards was a stock PD2/12 bought for a short-notice requirement in 1956, and not surprisingly Sheffield: as Romans might think of it the other city of seven hills. Halifax also took air-braked Regents at this time.

Topography was an important factor, but not a ruling one. Other factors to be borne in mind were engineering culture and climate. The major source of practical engineering education in the UK in the period was the railways, through their apprenticeship systems, and vacuum brakes were overwhelmingly the norm on British railways (and indeed British Railways) until well after the Beeching era, at the time of the Arab UF’s introduction only high-frequency commuter lines such as the Southern 3rd-Rail electric system, counterparts in large north of England cities such as Liverpool and Newcastle, London Underground and some steam-hauled LNER commuter services out of King’s Cross and Liverpool Street and equivalent LMS/LNER Glasgow suburban systems used air-pressure braking. The redoubtable Geoffrey Hillditch was not the only Chief Engineer nor General Manager of a UK bus operator to have served his time with the railways.

The British Isles can also get very cold in winter and as Mr Hillditch attests in his books Looking At Buses and A Further Look At Buses, this caused early-1950s air pressure braking systems to fail when the climate fell below zero Celsius for a while, albeit fail safe unlike some of the Clayton Engineeering Company’s Karrier products of the 1920s. He recalls his maintenance staff at Halifax having to apply blow-lamps to air lines to get brakes off in some hard winters; later systems –such as the one he specified for the Dennis Dominator– incorporate air-dryers.

Of course the original CD650 and all Freelines built until around 1954 had a different braking system, this was the Automotive Products Lockheed continuous-flow hydraulic braking system, major UK user being Birmingham and Midland Motor Omnibus Company (Midland Red) who used it on all of its own-build buses from 1946-69. As well as some inconvenient and expensive maintenance needs (from Mr Hillditch’s point of view when he had six to look after) it required type-trained drivers to work correctly in service and Peter Hendy, the London Assembly’s Transport Commissioner (the senior executive in Transport for London) recalls the BMMO D9 integral double decker he drove so equipped as “that blxxxy bus with no brakes”.

Conversely to these UK facts I understand that the Auckland Transport Board renewed its fleet from 1951 on the basis of 33ft long 8ft 6in wide dual-door single deckers, electrically or diesel powered. May I say that the use of Compression-Ignition engines was quite avant-garde for your country in that decade? At those dimensions it is perhaps not a surprise that the Leyland and AEC vehicles, which were both drawn up initially at 27ft 6in by 7ft 6in and whose engines developed 125 bhp were not considered powerful enough for Auckland’s challenging topography; as your handle on this site is related to the electrically powered vehicles Auckland took can you enlighten us as to the power of their motors and perhaps the maker of this vital component and also perhaps the control-gear?

As I understand it the people building electrical motors for trolleybuses at the time were Crompton-Parkinson, English Electric, GEC and Metropolitan-Vickers, the highest continuous-output offered in the UK by all four of them was 125bhp. This was considered more than adequate by LT for its famous Q-class BUT 9631Ts.
Braking systems for Auckland: The Regal IVs and Royal Tigers had air-pressure systems, did the BUT 9711Ts also have regenerative braking? This was patented by Stanley Guy, William Rees and the Rees-Stevens partnership in 1926, so was out of patent by the middle of the war. I know some of Nottingham’s Sunbeam and BUT trolleybuses had this by 1948.

The earliest Auckland Freelines must have had the CFS hydraulic brakes, did the later batches and were the drivers specifically-trained in the idiosyncrasies of its operation? (Halifax drivers and probably all of those in these islands not trained by Midland Red found it problematic: CF Peter Hendy earlier.) Glasgow’s one Freeline and its 26ft CD650 were both scrapped at seven years old, the body from the CD650 going onto a similarly-aged CVD6. FYS999 the CVD650-30 (Glasgow’s only rear-entrance 30ft motorbus) had air-pressure brakes but lost its power steering, air-servo to the gearbox and Daimler engine on successive overhauls. It was known to Glasgow bus drivers as ‘the bomber’ when originally-powered on account of its over-performance in Glasgow. It is running as part of the Glasgow Vintage Vehicle Trust collection in its out-of-service mechanical condition, with the air-system only serving the brakes and a 120bhp Gardner 6LW powering it rather than the 150bhp CD650 it was new with. I have ridden upon it so-preserved and it is slightly less ponderous than the shorter but similarly bodied PD2/24 Titans in GVVT care, that said FYS999 and the FYS and SGD Titans can keep up with current Glasgow traffic on a Sunday in October, unlike the utility Guy Arab 5LW reconstructed at the Scottish Vintage Bus Museum, Lathalmond. Sitting behind the driver on my rides in it, it has always felt marginal for power, the original twin-plate clutch and sliding-mesh gearbox with back-to-front shift pattern must have further deterred drivers.

Incidentally all British United Traction trolleybuses from its 1946 formation until 1953 were built at the Ham, near Kingston upon Thames, Surrey, factory Leyland established in 1918 to recondition RAF type lorries reclaimed from the War Department, in the 1930s this factory built the original Leyland Cub. The 9711T is particularly unusual as an export single decker built to AEC rather than Leyland design (may I ask its namesake if it has a frame cranked over the axles à-la Regal IV or CRT Worldmaster? I seem to recall the ETB1-3 had a frame straight in elevation like the Royal Tiger and normal Worldmaster. Later Crossley at Stockport built BUT trolleybuses, finishing with 30ft 9614T double deckers and 35ft RETB3 single deckers for Glasgow. Shortly after these were finished, Stanley Markland, works manager at Leyland from 1946 , whose first directorship was with BUT, became chief executive at Albion, replacing the last member of the founding families. The last BUT trolleybuses were built at Leyland, final examples of the LETB3 going to Portuguese municipals in 1964. I think the last Sunbeams went to Iberian operators at around the same time, although if the MF2 had followed the same path as the F4 and F4A, then it would have used a Guy-designed frame and axles.

I notice you think that the ideal Leyland Royal Tiger specification would be air-brakes and an air-actuated AEC preselector transmission. No home market Royal Tigers had this, but Leeds took 30 of the similarly specified PD2/14 Titan in 1954 before moving to the Pneumocyclic PD2 together with semi-auto Daimler CVG6s and AEC Regents. Of course London Transport had 2,111 Titans with the same driveline.

I’d not known of a 170 bhp rating for the Cummins V6 VIM, Roadliner buses were advertised at 150 and coaches at the full 192, PMT at one point de-rated its Cummins-powered buses to 135 and experimented withpedestal-type air-shifts to the transmission to prevent overspeed-events... As for the VINE eight cylinder, as I understand it, only Atkinson used it in the UK in a heavy-hauler called the Omega. The VIM and VINE engines were all imported from Indiana, the NTC straight six, built for Europe in Shotts near Motherwell, Lanarkshire, was considered too big and heavy for most haulage applications although it went into that cult-type, and certainly not a haulage vehicle, the Ministry of Transport 6x6 Atkinson motorway gritter.

Although Sir William Lyons was courted by Cummins to licence-build the VIM and VINE at the former Henry Meadows factory adjacent to Guy Motors, he did not complete on the deal; if he had the VIM and VINE would have been built and sold in the UK as Jaguar-Cummins. He deliberately kept himself informed on Daimler’s (and later Guy’s and Coventry Climax’s) products as he did on Jaguar’s, he is recorded in one of his biographies as being distressed by the shortcomings of 6000EH, the prototype Roadliner bus, and the Cummins V6 Fleetline (one guesses 7000HP) placed with Sunderland.

A business history of Rolls-Royce records that Sir William approached them for a lightweight V8 turbo diesel (Ford being in and then out of the action but BMC approving Jaguar’s approach) and an example using a Silver-Shadow block bored to 6.57 litres with a beefed up bottom end was on bench-test at Wolverhampton when BLMC happened.
Krupp, with a West German built haulage range, but one dependent on Deutz, MAN or Daimler-Benz engines, did sign such a deal with Cummins by 1964, and within three years they were out of the market. The last of their steel cabs went on LHD Atkinsons.

The Chrysler-Cummins VAL and VALE engines built in Darlington were no better than the VIM and VINE, the only PSV to have a VALE was a heavily modified Ford R226, (search Flickr for Whitefriars Ford Cummins) shortly after Chrysler getting control of Rootes, Perkins engines (6:354 and V8-510 to start with) went into the K-series Dodge which after a few years effectively replaced the C and V series Commers. Around the end of Roadliner production, after deploying Cummins engineers seconded from Columbus Indiana at Hanley, and allegedly Darlington and Bournemouth (who took 17 replacement VIM engines over 11 buses during the warranty period; the only ex-Bournemouth Roadliner surviving is the one refitted with a Perkins V8-510) Cummins admitted that the VAL and VINE (both designed for stationary generating applications) were not suited to stop-start operation.

The Guy Big J did later use the 500 series headless wonder, particularly in weight-critical applications, notably those mixer and light-artic ones. However from its 1968 announcement the next appearance of the headless wonder I can confirm was at the 1970 Earls Court show in the pre-production examples of the Lynx, Buffalo and Bison lorries, the Leyland National and the Bristol Omnibus Company RE (coded XRELL) on that manufacturer’s stand. The 500 was designed for maximum payload applications, the plan was that with an LMC rationalised Pneumocylic gearbox close-coupled using a charged coupling (and at this time LMC were trying to persuade haulage operators to take the Pneumocylic too, the splitter version going into the Super-Beaver, the Mandator V8 and the Gas Turbine Truck) the 500-series engine plus gearbox would weigh less than 1,000lb (454Kg). I wonder if Christchurch (NZ) had to take the 510 rather than a Gardner or the 680 in its RELLs because of your country’s axle-weight limits. I know that in 1971 or 1972 they took a Swift 505 3MP2R with a body sharing a number of features (front light-clusters and unusual seats among them) with the 1970 National show exhibit. Christchurch were very much an ACV fleet, am I right in saying that all their Regal IVs had Park Royal bodies and some of their Reliances were bodied by Crossley?

You mention a 33ft 6HLW-powered Atkinson in NZ, Sunderland had three of those (46-8: WBR246-8): the last Atkinson PSVs built and they were easily the most powerful single deckers in the fleet at the time, succeeding 1959-61 Reliances in that role. (Previous SCT management had some Arab III single decks with 6LWs but 1953-69 GM Norman Morton put those engines into double-deckers at the soonest opportunity, 5LWs from those going into the single deck Arabs.) Sunderland and Doncaster were the only UK operators who took mid-engined single deckers specifically designed for this intermediate length in the 1960s. (36ft by 8ft 2 1/2in being legalised in 1961 for all buses with effect from 1/1/1962.) They both wished to extend driver-operation and were mindful of the existing national agreement between the Municipal GM’s Committee and the Transport Unions that 45 seated was the maximum capacity allowed for driver-operated single-decks, unless subsequently individually negotiated and agreed. These three Sunderland buses were particularly odd in that they had SCG gearboxes (un-badged Leopard-style Pneumocyclics) but vacuum brakes, thus having both an exhauster (for the brakes) and a compressor (for the gears), both doors were powered from the electrical system. 46 was initially delivered with a David Brown constant–mesh gearbox but even though some of the Reliances were synchromesh and Sunderland’s previous two Atkinsons were front-engined 30 footers with constant-mesh gears powered by 4LW engines (Type L544LW) the driving staff refused to accept it. Of the three UFE Atkinsons for Sunderland, only 47 has not survived and a driveable facsimile of one is available to download for people with the Midtown Madness II driving game... Marshall-bodied WBR246-8 were also the first examples of the definitive BET style with peaks and double-curvature glazing at front and rear not built to maximum length, being registered between December 1963 and February 1964. Doncaster took its Charles H Roe bodied Royal Tiger Cubs (also B45D) in two batches, one in 1965 with flat-glass windscreens and on manual-transmission RTC1/1 in 1965, the second batch, Pneumocyclic RTC 1/2 arrived in 1967, and had peaked roofs with the Park Royal-Roe standard at the time of an Alexander windscreen and a BET style rear window. By the time the last of these had arrived, Leyland had decided that the short-wheelbase Leopard L1 and L2 and the Royal Tiger Cub would be rationalised into the PSU4 Leopard, which was much more RTC than L. I have ridden on Sunderland 46 and it is a refined and well put-together bus but with a rather higher floor line than a contemporary Bristol MW or Reliance, although the entry platform is lower than the saloon floor. A couple of years ago, just before he retired, David Dean of Classique (the Paisley-based vintage coach tour operators) showed two of his Leopards at a Glasgow Vintage Vehicle Trust Running day. The 1973 Panorama Elite III-bodied PSU4.4R (SCH40L) carried a Royal Tiger Cub Shield.

The national union-management agreement also explains why instead of the Panther being proposed to it (and most of the other larger Leyland customers) Manchester Corporation asked for a 33ft version. A Panther driveline layout could not accommodate the 600 or 680 to a 33ft length without breaking UK C&U rules on rear overhang. Manchester outright refused Panthers and said to Leyland that they had been briefed on a rival product (the Daimler Roadliner ) and it was available at 33ft. This is the wherefore of the most woeful failure of all post war Leyland Motors or LMC single deckers, the Panther Cub. Sunderland took three of these in 1965 before concluding negotiations with their driving staff and going for a massive re-equipment with 86 Panthers, 25 full-length Swift 505s, ten RELL6G and three Roadliners, all to then maximum length and width, dual door (B47D) and most to Norman Morton’s body design. Less than a year after Sunderland’s first Panther being shown at Earls Court, Manchester (who must also have re-negotiated on the basis of double-deck driver-operation being legalised in 1966) ordered 30, of which 29 were delivered thanks to a fire at Metro-Cammell’s Elmdon works. Both Manchester’s Panthers and Panther Cubs were withdrawn early and seemed to work better in Australia than the UK. As I say in my Wikipedia article about the Panther Cub, at least it provided the frame for the short-wheelbase AEC Swift 505, which between 1966-75 was quite a strong seller on the home market and had some business elsewhere.

With its short Swift 505s and the preceding Swift 691s (which they called Merlins, confusing the Swift 691 with a planned but not built export variant on the Swift /Panther theme, which would have used a Panther coach frame and Regal VI axles) and the 1965/6 experimental Atlanteans, Fleetlines and Reliances, London Transport returned (reluctantly) to air-pressure braking after its Routemasters all used the Lockheed full-power hydraulic system, which by all accounts is much more reassuring to drive than the CFS. The Fleetlines, Metro-Scanias, Metropolitans and Leyland Nationals London took in the 1970s were also air braked, and the Bristol LHS and LH (IIRR) air-over hydraulic, but of course all 16 or so FS Ford Transits vacuum. Thus London made sure that when it got its teeth into Leyland about Project B15, that Hydraulic brakes would be standard. They also persuaded MCW to build all of LTs Metrobuses with these. It is said of generals that they fight the previous war, the same is true of LT with its post-1950 change from air to hydraulic, when from 1985 LT was set to be devolved, downsized and de-regulated (the latter never happening) LT converted all of its Metrobuses to air-brakes and its TN-series Titans to air-over-hydraulic, the double-wishbone front IFS meant the front hub could not fit an air-brake unit, although the Olympian air brake system fitted on the back without a problem.

I did promise you I would re-read the relevant chapters of Doug Jack’s The Leyland Bus Mark 2 with regard to the BLMC export market products from Fallings Park, Wolverhampton. Doug Jack says (pp419 et seq.) ‘The Arab was withdrawn in 1971 and the last Warrior left the factory about three years later.’ He summarises the initial introduction of the Victory, ‘from 1956 initially with Gardner and Leyland horizontal engines… development of the Invincible truck…. most production to Belgium and Holland, with less frequent sales to Spain, Portugal, Greece and South Africa.’ He says the Victory J was introduced from 1969 ‘allowed by an expansion of the Guy Big J truck’: RHD only until 1972, vertical-front Leyland O680 with options of Gardner 6LX and 6LXB, with the rationalised Pneumocyclic or –I surmise Thornycroft– constant-mesh transmission, Guy hub-reduction rear axle, dual-line air brakes and wheelbase options of 18ft or 20ft 6in with entrance ahead of the axle and 21ft for the variant with entrance aft of the front axle. One prototype had a 500 engine. The AEC Ranger and some Clydesdale bus variants were discontinued in 1975 in favour of the Victory J. This gives me an end–date for the Ranger, which before I had puzzled over as the last examples were bodied in Montevideo circa 1978; 1975 makes sense as the Mercury, Marshall and small-engined Swift, together with their 505 engine died in the same year. He does mention the 1975/6 South African double deckers but not the later CMB/KMB and other Hong Kong examples. These, the Victory 2 series II, had Worldmaster CRT, rather than Guy Big J-style frames to reduce overall height, and the vast majority had Voith D851 transmission; all were 6LXB powered and the vast majority had locally assembled Walter Alexander CB-type CKD bodies, the rest similar units supplied by Duple-Metsec. It was a reliable bus but far from a stable one, the Wikipedia article ‘Leyland Victory’ contains a list of all the overturning incidents involving the type. Fallings Park also built most Scammell Crusaders, so if somebody ordered Big J4Ts with R-R Eagle engines and Fuller Roadranger gearboxes and similarly specified Crusaders, did they actualy believe they were dual-sourcing? One customer who took both was of course the state-owned haulge concern BRS, they also took nearly identical Seddon 32-Fours, but they were at least assembled by a different factory and one outside BLMC, although out of mostly the same parts; notably engine, gearbox and cab...

As for why later Arabs for CMB used CVG6 components, it was because Lyons was better at taking rationalisation decisions than Donald Stokes. Guy was to build lorries, Daimler Transport Vehicles buses and so if Guy needed bus components it could get them from Daimler.

Automotive Products of Birmingham in the UK licenced both the CFS and the later full-power hydraulic braking system from Lockheed Aircraft Corporation of the USA. The founders of that business, now known as Lockheed-Martin, were brothers from a family of Ulster immigrants into the US and their name at birth was spelt Loughead, they decided to re-spell it to US phonetics (or even fonetiks) after too many people called them Log-Head.

Best Wishes
Stephen Allcroft
Cardross
Scotland


Top
 Profile  
 
PostPosted: Mon Jan 27, 2014 10:53 pm 
Offline

Joined: Sat Mar 31, 2012 7:34 am
Posts: 39
Location: Mount Maunganui, New Zealand
Wow! Thanks, Stephen. That’s a major essay. I’ll need to respond a piece at a time.

On braking systems, my prejudice against the vacuum types is largely based upon observations and hearsay. For example, back in the late 1960s, one of the Auckland suburban operators, ABC, acquired a couple of ex NZRRS OPS3s, and these always seemed underbraked, with the drivers appearing to be just about standing on the pedals on the downhill sections. The Bedford SBs with the earlier air-suspended vacuum servo also seemed to be somewhat lacking in braking power. The change to the better vacuum-suspended servo, as introduced with the TK truck, happened I think at the end of 1961, at about the same time that the 330 in3 diesel engine arrived. One also heard of NZ truck operators in the 1950s fitting extra exhausters to their diesel-engined vehicles in order to have enough vacuum to operate trailer brakes. Back in those days it was expected that a typical “7-ton” truck would be able to haul a 12 ton gvw two-axle trailer. The gasoline-engined models, despite their greater power, often struggled, suffering from overheating. Thus diesel-engined variants, despite their lower power, were often chosen for this role. The Leyland Comet was an important model in this regard, although the original version with O.300 engine was probably struggling at 24 tons gcw or more. Still, old habits died hard. In the 1960s and into the 1970s Winstones in Auckland ran a fleet of O.400-engined Albion Reivers (or Super Reivers) that operated at 18 tons gvw and pulled 12 tons gvw two-axle trailers. They were rather slow.

That said, vacuum systems are probably easier to deal with in the “maximum moisture” temperature range, which is either +5 to -10 or +10 to -5 °C temperature range, I can’t remember which. Anyway, it’s likely applicable to a lot of the UK during the winter period, but hardly unique. It’s an odd fact that UK makers and operators had difficulties with systems and design approaches that the Americans had worked out satisfactorily back in the 1930s. Transverse vertical rear engines fall into this category. Was there an NIH factor? But most of the UK post-WWII trolleybus fleet was air-braked, apart from some of the Sunbeams that had the Lockheed constant-flow hydraulic system. (At least one BUT chassis displayed at a Commercial Motor Show had this system as well, but I am not aware that it was applied to any production vehicles.) So if air brakes could be made to work for trolleybuses, why not for motorbuses?

The Auckland post-WWII trolleybus fleet was air-braked with rheostatic, not regenerative braking. Whether there was any “automatic” regeneration at higher speeds on the top notches, which can happen with compound-wound motors, I don’t know. (The American GE MRC system had this feature).

The BUT 9711T fleet, all 55 with MCW bodies, had Metrovick 210 series motors of 135 hp, and the Metrovick version of the English Electric automatic acceleration control system with the hydraulic dash-pot. They were heavy vehicles, 15 tons gvw for 77 pax.

The BUT RETB1/2 fleet, 40 with Saunders Roe Rivaloy bodies (with some SARO external features) and 34 with Park Royal bodies, had BTH 210 series motors of 125 hp, I think. They were the first application of BTH’s then-new automatic acceleration control system incorporating the eddy-current device, and generally they seemed to be a bit smoother than the 9711Ts. They were lighter, at 14 tons gvw for around 83 pax. Note that both varieties of BUTs had shunting batteries, which would have upped the weight a bit.

The BUT 9711T/9721T was evidently put together in a hurry by AEC, mostly using motorbus components, to meet an early post-WWII overseas need for transit-type trolleybus chassis. The chassis-frame was cranked over both front and rear axles, and as best I can estimate, the mid-frame height was somewhere between that of say a Regal IV and the BUT RETB1. Generally it was Mark III-ish, and the steering column had the same outward lean that was found on the AEC motorbuses of the era. The rear axle had its worm gear offset to the left, and the latter was rather undersized for the job required of it, suffering short life as a consequence. The 9711T/9721T does not appear in any of the BUT literature that I have seen; I think it became a back-number once the definitive BUT chassis range was established. On the other hand, it fell to the AEC side to design the export rear-motored 9731T chassis, which never went into production. I suspect that the 9711T/9721T shared quite a bit of detail with the domestic 9611T/9612T, including the same or a very similar drive axle.

On the other hand the BUT ETB1 looks to have been the outcome of careful design work by Leyland. Its frame was cranked over both axles, and the mid-frame height was probably similar to that of say an OPS3. One can see OPS2 family features where they fitted, but otherwise the design was ad hoc. It shared the same 16¾ inch diameter brake drums, with piston actuators, as other air-braked Leylands of the time, including the super heavy duty trucks. But for example the rear actuators were axle-mounted rather than being frame-mounted with longer linkage as on the OPS2 family. The final batch of RETB1s, built (by Scammell) for Wellington in 1964, retained the same brakes and actuators, notwithstanding the updates that had been made on other models (itself an interesting story). The ETB1 drive axle was of the very heavy duty worm type with 9 inch centres.

Both the 9711T and RETB1/2 types were generally powerful enough for Auckland conditions. Of the two, the 9711T seemed to have the slight advantage on the hills, but whether this was attributable to its motor power or the control system settings I do not know. I am not sure if the final weak field notch was disabled as on the Wellington fleet in order to limit top speed, but it might have been so. Auckland had a “textbook” Ohio Brass overhead layout, including Selectric switches downtown, that was very well maintained until the mid-1960s, and so permitted relatively fast running. In contrast the Wellington overhead, mostly OB with some BICC) looked a bit second-class. And even when the new K&M elastic overhead was installed in the early 1980s, it never looked as good as that on the Swiss systems.

The main British competitor to the ETB1 was the Sunbeam MF2B. The first iteration of the latter looked rather like an F4 on to which a front frame extension had been grafted, and retained those unfortunately short front springs so characteristic of British practice. There were later improvements made under Guy aegis, albeit without change of designation. I suspect that unlike the case with the F4-to-F4A transition, which was marked by a change in toto from the Sunbeam to the Guy Arab IV chassis frame, the MF2B changes were more progressive. It required a dedicated frame. The rear-motored MF2R did not get past the prototype stage, and as far as I know, the six-wheeled transit chassis, the S7B, was offered but never actually built. The last Sunbeam MF2Bs went to Oporto in 1966, although the full trolleybus chassis range was still offered at the end of 1967. I suspect that it might have been discontinued with the formation of BLMC, but that is indistinct.

Both Auckland Freeline batches had the constant-flow hydraulic braking system, and it was troublesome at times, sticking charging valves being one of the issues. I am still not sure where they had the servo-type, as used on the CD650, or the Powervalve version though. It is on my list of things to do to get a close look at one to figure it out. They did have hydraulically-operated (as distinct from hydraulically assisted, as on the CD650) gearshifts, so getting stuck-in-gear was a failure mode that could and did happen. The original specification was for servo-type brakes and unassisted gearshifts, so the first Auckland batch was different in having the power-operated gearshift. That being the case, it seems not unlikely that they could have departed from standard in having the Powervalve braking system. They also had hydraulically operated doors, and AP-Lockheed data suggests that this facility was associated with the Powervalve system.

By the time the second batch was built, the Powervalve system had become standard on the Freeline, and the charging valve had been deleted. But as far as I know, the second batch were essentially identical to the first, braking-wise. So one cannot get to the right answer by logical deduction. The odd comment about heavyish pedals tends to point to the servo system, as the Powervalve system had, or should have had, a fairly light pedal.

The problems with the hydraulic braking system were not I think fundamental, but may have stemmed from lack of development, particularly in respect of seals. (In this part of the world, there is an ingrained expectation, fairly so or not, that British equipment, both road and rail, will leak oil and suffer from overheating.)

The railway influence on braking system expectations is an interesting one. BR was a sad case indeed. Firstly, the 1955 Modernization program really should have started back in 1948, but evidently top management could not see that – and maybe did not know enough to see it - and so allowed, probably by default, the mechanical folks to do as they wished, which in the case of the CME (although I don’t think that the position was so-named) was to play with steam locomotives. Anyway, the 1955 plan envisaged conversion from vacuum to air brakes, which was not such a big deal as most freight wagons of the time were unbraked (quite a staggering thought when viewed from this era) and the plan was to fit continuous brakes to all. But the operating level folks got in the way here, basically wanting an easy life that did not involve the extra effort required for a major transition. That is well recorded in the excellent book by Johnson and Long, “British Railways Engineering 1948-1980”. So vacuum brakes remained the norm until the later 1960s. The love affair with vacuum brakes extended to the Crown Agents, as well. Many of the “colonial” railway systems for which the Crown Agents acted as supply coordinators were vacuum-braked. The norm here, for good engineering reasons, with diesel locomotives was to fit air brakes to the locomotive and vacuum braking equipment for the train, and this was seen on BR’s fits generation diesel fleet. But the Crown Agents seemed to like the idea of fitting vacuum brakes to the locomotives as well, and this was done for English Electric-built orders that went to Ghana, Nigeria and Malaya amongst others. For the Malayan fleet, Harry Gresham’s augmented two-pipe system was fitted, and this had a rather interesting and amusing consequence. The Malayan locomotive design was adapted for a subsequent Sudan order in which speed of delivery was an issue. So the two-pipe vacuum braking system was retained, albeit in improved form. Sudan Railways then adopted it as standard, and insisted on its fitment to subsequent locomotives deliveries from Cockerill and Hitachi, which builders might have been a bit astonished by what must have seemed to be a retrograde approach. Additionally, some late 1960s Hitachi DMUs supplied to Sudan had Harry Gresham’s other two-pipe vacuum system, the same Quick Release version as fitted to BR Mk I DMU fleet.

Cheers,



Attachment:
BUT ETB.1 1954-09 p.01.jpg
BUT ETB.1 1954-09 p.01.jpg [ 357.07 KiB | Viewed 3546 times ]


Attachment:
BUT 9612T 1954-09 p.01.jpg
BUT 9612T 1954-09 p.01.jpg [ 433.36 KiB | Viewed 3546 times ]


Attachment:
Sunbeam TB 1949 p.06.jpg
Sunbeam TB 1949 p.06.jpg [ 555.69 KiB | Viewed 3546 times ]


Attachment:
Molloy p.14-87.jpg
Molloy p.14-87.jpg [ 155.49 KiB | Viewed 3546 times ]


Attachment:
Molloy p.14-89.jpg
Molloy p.14-89.jpg [ 138.44 KiB | Viewed 3546 times ]


Attachment:
G&C Ad DRT 1962-06.jpg
G&C Ad DRT 1962-06.jpg [ 173.22 KiB | Viewed 3546 times ]


Attachment:
Jane's 1969-70 p.54 adv.jpg
Jane's 1969-70 p.54 adv.jpg [ 1.34 MiB | Viewed 3546 times ]


Top
 Profile  
 
PostPosted: Tue Jan 28, 2014 1:36 am 
Offline

Joined: Sat Mar 31, 2012 7:34 am
Posts: 39
Location: Mount Maunganui, New Zealand
9711T wrote:
The last Sunbeam MF2Bs went to Oporto in 1966, although the full trolleybus chassis range was still offered at the end of 1967.


No, Coimbra not Oporto.


Top
 Profile  
 
PostPosted: Tue Jan 28, 2014 11:44 am 
Offline

Joined: Tue Jan 24, 2012 4:44 pm
Posts: 169
Thanks one again 9711T and my apologies to you and everybody else for posting such a long screed, just as ever your previous posts raised a lot of interest which set me thinking...

Further apologies to you and everybody else for posting it twice with slightly different edits... It had beeen a long day...

Thanks especially for more on the railway angle. You're right that Robin Riddles was not called the CME of British Railways, his job title was a sentence that does not easily become an acronym, and he was lead member of a triumverate who covered CME functions. Such was the management culture of the British Transport Commission; which august body was generally headed by a retired General.


Stephen Allcroft


Top
 Profile  
 
PostPosted: Tue Jan 28, 2014 11:31 pm 
Offline
Site Admin

Joined: Wed Jan 11, 2012 7:29 pm
Posts: 87
Don't apologise! Great posting everyone!


Top
 Profile  
 
PostPosted: Tue Jan 28, 2014 11:37 pm 
Offline

Joined: Sat Mar 31, 2012 7:34 am
Posts: 39
Location: Mount Maunganui, New Zealand
Attached is some information on the Daimler CD650 braking systems.

Note that the optional air system was not simply a homologue of the hydraulic system.

The gearshift was changed from hydraulically-assisted mechanically operated to air pressure operated with no mechanical reversion.

The handbrake was changed from hydraulically-assisted mechanical operation to mechanicl operation with air-pressure assistance using the rear brake cylinders via a pull-valve in the handbrake linkage.

The service brake (footbrake) was changed to fully-powered oepration with air cylinders at each wheel. The "hydraulic" version had fully powered front brakes, operated by hydraulic fluid from the pressure system, combined with rear brakes that were hydraulically operated from the master cylinder with boost from the pressure system. The pressure system and master cylinder were separate circuits.

Cheers,

Attachment:
CD650 Hydraulic Servo p.01.jpg
CD650 Hydraulic Servo p.01.jpg [ 136.55 KiB | Viewed 3541 times ]


Attachment:
CD650 Hydraulic Servo p.02.jpg
CD650 Hydraulic Servo p.02.jpg [ 454.57 KiB | Viewed 3541 times ]


Attachment:
Daimler CD650 SD p.03,04.jpg
Daimler CD650 SD p.03,04.jpg [ 481.24 KiB | Viewed 3541 times ]


Top
 Profile  
 
PostPosted: Wed Jan 29, 2014 9:22 pm 
Offline

Joined: Sat Mar 31, 2012 7:34 am
Posts: 39
Location: Mount Maunganui, New Zealand
Looking again at vacuum brakes, or more precisely, vacuum-assisted hydraulic brakes, vacuum suspended systems were better than air suspended systems, but the UK industry was a bit slow to adopt them. Railway vacuum brake systems were of course of the vacuum-suspended type.

By way of an example, Leyland introduced the Hydrovac (vacuum suspended) remote servo with the CS3 iteration of the Comet truck in 1959, and made quite a feature of it in its literature. Albion had had an earlier history, and as far as I know the Hydrovac arrived with the underfloor-engined Claymore and was then used in the Nimbus, Aberdonian and then the Chieftain CH and Victor VT. But the Comet CS3 would have been better off with an air-pressure assisted system. At the time, the Airpak servo, direct counterpart to the Hydrovac, had yet to arrive in the UK despite being well-established in the USA. So manufacturers wanting a relatively lightweight system were obliged to use the air actuated hydraulic approach, as installed on the Albion Reiver RE series. Quite why this was not at least an option on the CS3 is hard to fathom. The Airpak did arrive in the UK in the second half of 1960, and as far as I know it was offered as an option on late CS3 production. Certainly it is mentioned in the brochure for the AWD 4x4 conversion. Of course, Leyland stepped right out of this debate with the fully air-braked 12C in 1962, which was then unusual in weight class and in combining air brakes with 8-stud wheels, although within LMC there were the precedents of the Albion Super Reiver, and before that, the Tiger Cub and Leopard L.

Albion used the air actuated hydraulic braking system, similar to that on the Reiver, for the Chieftain Super Six and then for the Viking, so one might say that by the early 1960s, the wisdom had been received.

Attachment:
Comet CS3 1961 p.04.jpg
Comet CS3 1961 p.04.jpg [ 972.45 KiB | Viewed 3538 times ]


Attachment:
Leyland Comet CS3 4x4 196205 p.06.jpg
Leyland Comet CS3 4x4 196205 p.06.jpg [ 989.79 KiB | Viewed 3538 times ]


Remote servo units would not have suited Bedford, who had used tandem master cylinders at least as early as the WWII QL, and who saw a direct mechanic connection between the pedal and master cylinder as being essential. Thus it stay with the traditional vacuum master servo until the TK trucks of 1960, for which Clayton Dewandre developed new master servos, suspended vacuum for gasoline-engined vehicles (although available with diesel-engines to special order) and air pressure for diesel-engined vehicles (although also used on some gasoline-engined vehicles). These were pull-type units, and the vacuum version looked to be concentric but was not really. These were then used on the VAS, VAL and VAM from their respective inceptions, and the SB and TJ ranges were swung over, I think around the same time that the 330 in3 diesel engine was introduced. Strangely, the R 4x4 retained the old-fashioned vacuum master servo until the end. That may have been the result of military requirements, although I have one reference that suggests that in the early days of this model, the air pressure master servo was fitted.

Attachment:
Bedford TS1074 197306 p.24.jpg
Bedford TS1074 197306 p.24.jpg [ 998.84 KiB | Viewed 3538 times ]


Attachment:
Bedford TS1074 197306 p.61.jpg
Bedford TS1074 197306 p.61.jpg [ 989.61 KiB | Viewed 3538 times ]


Attachment:
Bedford TS1074 197306 p.62.jpg
Bedford TS1074 197306 p.62.jpg [ 967.49 KiB | Viewed 3538 times ]


Attachment:
Bedford TS1074 197306 p.81.jpg
Bedford TS1074 197306 p.81.jpg [ 992.19 KiB | Viewed 3538 times ]


Attachment:
Bedford TS1074 197306 p.82.jpg
Bedford TS1074 197306 p.82.jpg [ 983.05 KiB | Viewed 3538 times ]


Information I have on the progress of BMC, Commer, Dodge and Ford into the air-assisted hydraulic and/or air-actuated hydraulic brakes is limited, but of these, Commer may have been the first mover, presenting the air pressure option as desirable for use in overseas, high altitude operations.

Cheers,


Top
 Profile  
 
PostPosted: Wed Jan 29, 2014 9:43 pm 
Offline

Joined: Sat Mar 31, 2012 7:34 am
Posts: 39
Location: Mount Maunganui, New Zealand
Re frame profiles, the Worldmaster had cranked sections over both the front and rear axles. The difference between the CRT and ERT variants was not in the frame profiles, but simply in the spring cambers. The CRT would have been an adequate, if not brilliant basis for a trolleybus chassis once the ETB1 had gone, and in fact the Arnhem LVB6T fleet of 1969 was probably not far off from having been an electric CRT2.

Given that the preceding Tiger Cub had the frame mildly cranked over the rear axle only – as had the royal Tiger before it, I suspect that the choice in the Worldmaster case was to facilitate the CRT variant.

The Leopard L inherited the Tiger Cub frame. But as far as I know the PSU3 had a straight frame from the start. I do not have proof-positive, but I suspect that the PSU3 was derived directly from the Royal Tiger Cub RTC1. The engineering for the latter included the beefing up required for 13 tons gvw, including the use of 10-stud wheels. The PSU3 was also 13 tons gvw, although with an 11¼ ton option for the UK domestic market. The Lion PSR1, despite being a Worldmaster derivative, had a straight frame, as did the Rhodesian 6x2 Worldmasters.

Attachment:
Worldmaster CRT1.1.jpg
Worldmaster CRT1.1.jpg [ 127.2 KiB | Viewed 3538 times ]


Attachment:
Worldmaster ERT1.1.jpg
Worldmaster ERT1.1.jpg [ 136.77 KiB | Viewed 3538 times ]


As best I can determine, only Auckland and Sydney received Royal Tigers with AEC preselector gearboxes, 50 each, in both cases by special request. Sydney was influenced by an LT consulting visit in the late 1940s, and also acquired preselector-fitted OPD2 and OPS2 models. Interestingly, the latter followed the AEC pattern when it came to mounting of the gearshift head and shaft, with the shaft angled backwards and inwards to meet the floor more-or-less behind the steering column. The Royal Tigers had a much neater installation with the shaft near-parallel to the steering column. The Auckland Royal Tigers “win” by virtue of their excellent Rivaloy bodies. Auckland reached its own conclusion on preselector gearboxes basis its own survey of worldwide practices in the late 1940s. Understandably, it liked the modern American transit bus concept, but it was impressed by the efficiency and ease of operation of the British powertrains, diesel engines and epicyclic transmissions, and anticipated that although at the time such were available only in the outmoded vertical front engine format, that it would not be too long before they were fitted to modern chassis types. That must have been a widely held viewpoint, hence the relatively modest sales of the OPS2/3/4 chassis, often acquired as stopgaps, followed by the floodgates opening once the OPSU1 & 2 became available.

Re Christchurch, NZ, its AEC Regal IV fleet carried both Crossley and Park Royal bodies. The “short” and “long” Reliances had Park Royal bodies, and the “new” Reliances had NZMB bodies, more details to follow. By the time the “new” Reliances were acquired, the general mood favoured local production where possible. The same happened with Wellington, whose first batch of Reliances had MCW Hermes bodies, whilst its second had MZMB bodies of rather unattractive appearance. Apparently some serious negotiating was required to allow half of the final BUT trolleybus order to be bodies by MCW.

Attachment:
Crossley p.03.jpg
Crossley p.03.jpg [ 820.95 KiB | Viewed 3538 times ]


Attachment:
Leyland Journal 1964-05,06 p.205.jpg
Leyland Journal 1964-05,06 p.205.jpg [ 674.54 KiB | Viewed 3538 times ]


The Christchurch Regal IVs were nicely proportioned buses, perhaps just a tad behind the Auckland Rivaloy-bodied Daimlers in overall aesthetics. On a visit to the Ferrymead museum in 2010, I asked my better half to pick what she thought was the best looking bus from amongst a Regal IV, short Reliance, RELL with BET-style body and RELL with VST-style body, and the Regal IV won.

Cheers,


Top
 Profile  
 
PostPosted: Wed Jan 29, 2014 10:07 pm 
Offline

Joined: Sat Mar 31, 2012 7:34 am
Posts: 39
Location: Mount Maunganui, New Zealand
Stephen Allcroft wrote:
Thanks especially for more on the railway angle. You're right that Robin Riddles was not called the CME of British Railways, his job title was a sentence that does not easily become an acronym, and he was lead member of a triumverate who covered CME functions. Such was the management culture of the British Transport Commission; which august body was generally headed by a retired General.


Much of what happened in the early BR period was covered in the writings of E.S. Cox, who was Riddles’ “right-hand man” on the design side. He was an engineer who was a very good technical writer, in the same rare class as Alan Townsin. Cox was understandably defensive about the early BR era, but that does not materially detract from the value of his output. In particular his book “Locomotive Panorama, Volume 2” is worth reading.

Another very good author was R.M. Tufnell, and his book “The Diesel Impact on British Rail” is probably the definitive work on the BR dieselization program. Being more of an engineering history book, it did not have much circulation in railfan circles. Tufnell’s book on the BR DMUs is also very good, and pertinent here because it provides relative performance information on the AEC, Leyland and Rolls Royce engines used in the 1st generation fleet.

Cheers,


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 25 posts ]  Go to page Previous  1, 2, 3  Next

All times are UTC


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group