User:Stephen Allcroft/sandbox

The Leyland Titan PD series was a forward-control chassis with a front-mounted engine designed to carry double-decker bus bodywork. It was built mainly for the UK market between 1945 and 1969, the OPD1 and OPD2 were specific Export variants, although the PD3 covered home and export requirements in the one model range.

The type was widely used in the United Kingdom and it was also successful in export markets, with numerous examples shipped to Australia Ireland India Spain South Africa and many other countries, both new and second-hand. All Titans were right hand drive regardless of the rule of the road in customer countries.

Wit over 14,000 sold at home and at least another 1,000 overseas, the Titan PD and OPD was the best selling double-deck bus of its time and one of the best selling buses of all time. After Leyland ended the production of the Leyland Titan in UK, Ashok Leyland of India took up production and marketed the bus in South Asia as the Ashok Leyland Titan, which, in much developed form, is still in production.

PD1
Unlike AEC, who initially re-introduced pre-war models, Leyland announced in 1945 for 1946 delivery a brand new Titan, only the front axle was similar to that of the TD7, every other component was new, although the standard Leyland steel-framed body was similar in structure and outline to the pre-war model, the lower saloon seats were re-spaced, the cab slightly extended, given a larger offside window and widened, the upper saloon was panelled on the inside for the first time. P is believed by some to stand for post-war, but the feeling within Leyland was that it stood for Passenger, the D stood for double-deck and the Titan PD1 which was developed under the TD9 designation was directly comparable to the Tiger PS1. Among the new features was the E181 7.4 litre engine which was a development of a pre-war 6.2 litre unit used in some TS8 Tigers and the sole LS1 prototype. The revised bore dimensions came from the version used in the Leyland Matilda tank. It was a six-cylinder pushrod-OHV unit which developed 100bhp at 1.800 rpm and 328 lb ft of torque at 1,150 rpm. These were slightly better figures than the larger pre-war design 8.6 litre OHC engine, but fuel economy was also superior, although it was a much harsher-sounding engine. The TD7’s flexible engine mounting was not 100% successful and so the PD1 reverted to a rigid engine mounting. The gearbox was a four-speed and reverse constant-mesh unit, with helical gear trains for second and third gear. Brakes as standard were triple-servo vacuum. A new larger radiator was fitted and its filler-cap was offset to the nearside to allow the driver’s cab to be wider, the nearside windscreen pillar running down the vehicle centre-line.

Dimensions of the PD1 were 26ft long by 7ft 6in wide, over the years of production there were a number of variants, these were as follows.

PD1A This was introduced in Autumn 1946. The only difference between this and the standard PD1 was that rubber bushes sourced from Metalastic Ltd were used in place of copper bushes in the spring shackles. It seems this produced a more stable bus, notably Barton Transport had an initial tilt-test failure when they in 1957 they first refitted a 7ft 6in wide Tiger PS1/1 Chassis with an 8ft wide double deck body, but fitting PD1A style spring bushes cured the problem, from early 1947 the PD1A had supplanted the PD1 in production. This variant, like the PD1, sold generally across the UK. Barton for instance taking PD1s in 1946 and PD1As in 1947, all with bespoke forward entrance lowbridge bodies by Duple. A number of PD1As had standard Leyland outline bodies licence-built by Walter Alexander Coachbuilders two of these were supplied in completely knocked down form for the Londonderry and Lough Swilly Railway Company who had them assembled in Derry. These were the first of many CKD Alexander bodies, construction of such later becoming a speciality. The SMT group also took Leyland-style Alexander bodies and the British Transport Commission had examples with Eastern Coach Works bodies of similar appearance to those on their standard Bristol K series double-deckers; in addition Bristol Tramways and Carriage Company had similar bodies built by its own Brislington Body Works and local private-sector coachbuilder Longwell Green Coachworks. Other coachbuilders building the Leyland body under licence for the PD1, PD1A and 26ft PD2 were John C. Beadle of Dartford, and Salmesbury Engineering of that Lancashire town, Alexander bodies on other chassis of the era also had a very Leyland-like appearance, presumably covered by the licence agreement. PD1/1 This was supplied exclusively to the City Coach Company of Brentwood, whose main service was an inter-urban run from Wood Green in East London to Southend-on-Sea in Essex, the twenty vehicles delivered to City had bodies by Alexander, J.C. Beadle of Dartford and Charles Roberts of Wakefield, completed in 1946/7. It’s not clear why these vehicles had a different suffix number although it may be that they had higher-ratio back axles.

PD1/2 This version comprised thirty vehicles, all supplied to Bolton Corporation during 1947; 15 had Northern Counties bodies and 15 Manchester-style bodies by Crossley. These were all 56 seaters (H30/26R) and they had the same dimensions as the standard PD1, but the brakes were air-pressure operated, the first use of this on a production Leyland bus. Bolton were early in the UK in standardising on air brakes some operators taking Vacuum brakes on buses as late as 1967, when AEC finally discontinued the option on Reliances and Regents.

PD1/3 In autumn 1946 the construction and use regulations were revised, allowing a maximum width for buses of 8 foot, rather than the previous 7 foot 6 inches, provided the Traffic Commissioners approved the use of wider buses on routes, in the same way as they already had the power to approve double-deck buses on a route-by-route basis, also the gross vehicle weight for a double deck bus was increased to 12 tons from the wartime figure of 11 tons. The PD1/3 differed from the PD1 in that it had wider axles, being designed for the 8 foot width, Oldham Corporation quickly obtained clearance for all their routes and in 1947 DBU244 with C.H. Roe H31/25R body became the first 8 foot wide motorbus built for service in the UK. Oldham took in total 50 similar buses in 1947/8. Manchester Corporation were also early customers for the wider bus, they followed up their initial 1946 batch of fifty PD1s with a 1947/8 order for 100 PD1/3 with 58-seat (H32/26R) bodies to their standard outline by Metro-Cammell. During 1948 Ribble Motor Services who had obtained permission to use full-width double-deck coaches on their express services from East Lancashire to Blackpool received 30 such with bodies by H.V. Burlingham of Blackpool, they had full-width cabs, electrically-powered folding doors to the rear platform, which itself was built-up to saloon level allowing a small luggage boot, the body-design, with additional luggage stowage over the rear wheel arches, had generously radiussed windows, two sunroofs on the upper deck and although to Lowbridge layout (the Leyland patent on this expired in 1937) were fitted out to full coach standards for 49 passengers(FCL27/22RD), liberal use was made of chromium-plated steel trim and they carried the cream coach livery with red relief rather than the bus livery of red with cream relief, they soon became famous as the White Ladies, and so successful that a further twenty similar vehicles on PD2/3 chassis with East Lancashire bodies were added in 1951.

The PD1 range ceased to be catalogued at the end of 1947, replaced by the PD2,which had been announced at the end of 1946 but in 1952 Central SMT took a final batch of PD1A with standard Leyland lowbridge bodies; this was ironic in that Central was the first operator to use the PD2 prototype to carry passengers, which is why it carried the Lanarkshire registration CVA430 and they took PD2s in 1948, 1950, 1951 and subsequently, also taking PD1As in 1949, However Central jealously guarded its reputation as the most profitable fleet in the Scottish Group, one reason for which was its fierce cost-control. Over 5,000 7.4 litre engined Leyland buses were built, but the majority of those were Tigers, mainly because the PS1 lasted longer in volume production, still about 1,950 PD1 Titans were built, most between 1945-8.

OPD1
This was the first Leyland bus designed specifically for export, O stood for Overseas. It had a similar frame to the home-market PD1, albeit made of marginally-thicker steel but the dimensions were larger, wheelbase went up to 17 feet 6 inches compared to the 16 foot 3 of the PD1, it was designed to take bodies up to 27ft 6in long, 18 inches longer than regulations allowed for the home-market model. The other major difference to the PD1 was that it (and the similar Tiger OPS1) were still fitted with the pre-war pattern 8.6 litre OHC engine, by then numbered E174. The largest market was in New South Wales,Australia with the Department of Government Transport taking ninety of the 93 exported there during 1946/7, with H33/28R bodies, half by Clyde Coachbuilders and the rest by Commonwealth Engineering. Coras Iompair Eireann, the Irish state transport operator, bodied twenty for its own use, H36/30R to its own licence-built Leyland-derived design. It added them to the R-class, established with Dublin United Tramway’s first all-Leyland TD4 in 1935. The only Leyland bodies fitted to the OPD1 were four for South Western Bus Company, Ceylon, and two for Lisbon Tramways. Lisbon’s having reversed staircases to suit the right-hand rule of the road, although they retained right hand drive. Madrid Municipal Transport took East Lancashire Coachbuilders bodies to similar layout on five OPD1s and two OPD1A, believed the only such built, all seven of these carried large plates on the engine cover reading “El Ómnibus Ingles Leyland” which is perhaps best translated as “Leyland, _The_ English Bus”. Other markets for the OPD1 were South Africa where 31 had locally built bodies, most going to the Cape Tramways group in Cape Town and Cape Province, and Argentina, where 34 were ordered by Leyland’s concessionary Prudens Lda., some of which were bodied as 31-seat single-deck coaches: Argentina being a major customer for similar but longer Tigers.

PD2 (non-London 26 foot versions)
The E181 was regarded by Leyland as an interim power unit, a stop-gap until a better power-plant came on-stream, thus the initial post war Leyland lorry so powered was called the ‘Interim Beaver’. The definitive power-plant for full-size post war Leylands began to be fitted to Beavers, Octopuses, Steers, Hippos etc. from 1946. Leyland at this time stopped using the E-number system for engines (at least externally). This new power unit was named after its displacement in Cubic Inches (US technical influence during World War Two led to a standardisation in the British heavy-vehicle market on Imperial dimensions until the late 1960s). Thus was named the Leyland O:600, O for oil, which was British engineering parlance at the time for compression-ignition engines, rather than naming the German Rudolf Diesel and 600 for a 600 cubic inch swept volume, equating to 9.8 litres. The only contemporary heavy vehicle compression-ignition engines built in Britain of equivalent displacement were the AEC 9.6 litre (from 1939) and the Albion 9.1 litre (from 1937). In its application to the Titan, the O:600 was rated at 125bhp at 1,800rpm, with peak torque of 410 lb ft at only 900rpm, these increases in performance resulted in an under-stressed engine, capable of giving lively yet economic performance, with unprecedented, and it seems unsurpassed ability to run day-in, day-out between overhauls. A major structural feature of the O:600 was that the dry-liner cylinder block and crank-case were cast as a unit, the first production UK heavy vehicle engine to feature this, although by 1945 Leyland had detail drawings of a similar but smaller engine design commissioned by the UK Government during Wartime from Napier which was to become the Leyland 300. Like the 7.4 litre engine the 600 was a six-cylinder direct-injection pushrod overhead valve unit, but the cylinder head was split into two, with each head and gasket unit covering three cylinder bores, other important features designed to enhance reliability were a gear driven, rather than chain drive, camshaft, mounted lower in the block; a nitrided crankshaft running in strip-bearings and chromium-plated piston-rings. The 600 which was also much quieter than the 7.4 continued in production until 1972, becoming almost legendary in its renown.

Although design work on the PD2 had started during wartime under the working title ‘9.8 litre TD9’ it was much more than a PD1 with a bigger engine, the frame was completely redesigned, with the longitudinal members carefully-graded in depth so that no part was overstressed nor over-engineered. The 600 was fitted into the chassis on a three-point flexible mounting and after a larger clutch unit the new gearbox which still had helical gear trains in second and third now also had Synchromesh operation on all but first and reverse, a pioneering feature in a full-size British bus chassis.

PD2/1 Although the prototype was called PD2 when it appeared in 1946, carrying an Alexander-built Leyland design body identical to those on PD1, and carrying the evocative (and very non-standard) chassis number EX1, it was decided that the initial production version would be called the PD2/1. The PD2/1 shared 26ft by 7ft 6in chassis dimensions and 16ft 3in wheelbase with the PD1, and had a similar triple-servo vacuum braking system, the first true PD2/1 (a pre-production bus) was chassis number 470848 which had the first standard Leyland body for the PD2, it went to Birmingham Corporation, who registered it HOJ396 and operated it until 1968. Central SMT had a PD1 with PD2 engine and transmission, chassis number 47009, which they registered CVA391. The first production PD2/1 complete with Leyland body went to Todmorden Joint Omnibus Committee, in July 1947 and another early example went to the Northern Ireland Road Transport Board. Birmingham followed up its initial interest by taking no fewer than 200 with bodies by Brush (100), Leyland and Park Royal (50 each) until 1949 as part of a complete fleet replacement which ran from 1946-54 and included tramway and trolleybus replacement. The standard Leyland body for the PD2 differed only slightly from that on the PD1, by having the front offside mudguard extended around the front of the cab, where the PD1 had the cab front panel sweeping down to a lower level. PD2/2 was reserved for an air-braked 7ft 6in wide Titan, but it became one of a number of codes raised but not produced.

PD2/3 was the type code for the 8ft wide vacuum-braked version, in order to use standard front-glazing in both versions of the standard jig-built Leyland body, the version for the PD2/3 had a marked inward taper toward the front, starting at the lower-saloon bulkhead, which feature continued on all wide Titans bodied by Leyland until 1954. PD2/4 was the air-braked equivalent to the PD2/3 of which 115 were built, the majority of those going to Bolton, with the remaining 15 going to neighbouring Bury, Bolton took Leyland Bodywork, Bury Weymann.

PD2/5 sold 100 to one customer, Blackpool Corporation, all of which had H.V. Burlingham fully-fronted concealed radiator central-entrance bodies, to a similar streamlined outline to the resort’s famous trams, it was mechanically identical to the PD2/4 but to accommodate the Blackpool body design the frame had no down-sweep after the rearmost spring hanger but did have a re-shaped nearside chassis longitudinal to reduce step height on the air-powered two leaf sliding entrance doorway. Another variant for which a code was raised was for a Manchester order for 8ft wide vacuum-braked Titans without the rear drop-frame extension, as Manchester’s standard body was designed to carry the rear entry platform without chassis-framing, initially to be PD2/6, these were coded PD2/3.

OPD2
The OPD2 combined the revised frame and driveline of the PD2 with the dimensions of the OPD1, thus it had a 17ft 3in wheelbase suitable for a maximum bodied length of 27ft 6in, with 8ft width standard; the only other differences from it and the PD2 was that the frame was made of 9/32in rather than 1/4in steel and the rear axle worm-wheel was of a slightly larger diameter; only two versions were catalogued, the OPD2/1 had vacuum brakes and the OPD2/2 air. The largest customer was Coras Iompair Eireann who took over 500, as well as one batch of 100 PD2/3 with Bolton-style Leyland bodies and a further 50 all-Leyland PD2/1 and PD2/3 from a frustrated South African order, the rest of which was shared between THC Crosville and Hants & Dorset (these were the only PD2s sold to THC) and BET-group Ribble, they were the first Highbridge buses with Ribble and the only full height buses to be bought by Hants & Dorset. Another export customer to take domestic-type Titans was South Western Bus Company of Ceylon which took a batch of standard all-Leyland PD2/1 in 1949. After CIE the largest customer for the OPD2 was the New South Wales DGT who took over 300, triple-sourcing its double deck requirement with AEC Regents and Albion Venturers.

The RTL and RTW
Since its formation as a statutory corporation in 1933, the London Passenger Transport Board had a 30 year contractual obligation to source 75% of its buses from AEC and in 1938-9 worked with AEC on a revised version of the Regent to better suit London operating practice, following on from the experimental STD Titan TD4’s of 1936 it had a large-displacement engine running under less stress, other innovative features were an air-pressure system not only working the brakes but also the change-speed pedal on the pre-selective gearbox, which was built by AEC to Self-Changing Gear Company and Daimler Motor Company patents, this was coded RT and the initial 161 built had LT chassis codes 1RT and 2RT and entered service between early 1939 and late 1940, after the war, AEC got the initial order for a further revised version, LT chassis code 3RT, which was designed in conjunction with the Aldenham Bus Overhaul Works to be regularly re-built on a flow-line system, it took some time for AEC to get the RT into production and in 1946-8 LT took pre-war type Regents and Leyland Titan PD1s as stopgap double-deckers, by 1947 AEC had the RT in production, but it could not build enough of them quickly enough for LT, so they asked Leyland to supplement production from 1949. The initial LT version of the PD2 had a frame identical in shape to the 3RT, and a similar low bonnet, with a radiator outline unlike the standard Titan, the Leyland O:600 engines were to be supplied without the standard air-cleaner to the engine induction, because LT did not believe in it, one other difference between the RT and the standard PD2 was that the wheelbase was one inch longer at 16ft 4in, identical to the AEC RT in order to standardise body mountings, the steering column was also more upright than standard PD2s for the same reason: like the 3RT there was no frame aft of the rearmost spring mounting, the rear-platform being cantilevered from the bodywork. AEC-produced steering and pre-selective transmission units were included as were air-pressure brakes. The fluid flywheel and epicyclic gearbox were mounted separately in the chassis from the engine. Because LT chose the heavier-gauge steel for the chassis and the larger rear axle worm-wheel was specified, Leyland initially coded the London orders OPD2LT, but later called the RTL type PD2-7RT and the RTW PD2-6RT, following their LT engineering codes. As in the past, not only with buses but also with trolleybuses LT tended to give production of standard types to AEC and work with Leyland on experimental or innovative types, thus 500 of the Leyland order were the only steel-framed RT-type buses and had Leyland-built 8ft wide bodies, initially LT were going to class these as RTL1-500, so the first of the 7ft 6in wide version entered service as RTL501, some months before the RTWs, as London decided to re-classify the wide-bodied all-Leyland versions. As well as RTL501, a further 1,630 narrow Titan PD2-7RT were produced for London, production running into 1954.

Longer PD2’s
In June 1950 there was a further revision to the construction and use regulations, 8ft width no longer required special permission (by that time the Metropolitan Police were allowing RTWs to work in Central London, even including Westminster) and maximum length for double deckers was increased to 27ft, as a result, Leyland raised a new set of variant codes for the PD2, these having a wheelbase of 16ft 5in. The standard Leyland body was revised also. The new type codes for the Titan were:

PD2/10 7ft 6in wide, vacuum brakes; PD2/11 7ft 6in wide, air brakes; PD2/12 8ft wide, vacuum brakes; PD2/13 8ft wide, air brakes; Of these most found general favour, but the only customer for the PD2/11 was Leeds who took 20 in 1955, another model almost exclusive to Leeds was the PD2/14 which was similar but had an AEC fluid flywheel and pre-selective gearbox of the type fitted to the RTL and RTW, Leeds took ten of the eleven built, the other going to Walsall.

Another rare variant was the PD2/9, which was almost identical to the PD2/10, save that the chassis was modified to accept a lower-profile central-gangway double-deck body, built to around 14 foot high, about 6 inches lower than normal for a ‘highbridge’ design, all nine of these were built for St Helen’s Corporation, bodied by D.J. Davies of Merthyr Tydfil.

NTF9 was a PD2/12 as built in early 1953 but was converted to air-brakes when it was the first bus to receive a prototype Pneumocyclic gearbox, sometimes quoted as PD2/15, it carried a standard Leyland body and after demonstration-duties was sold around 1955 to T & E Docherty, part of the A1 Service consortium running buses around Kilmarnock, it continued in service with A1 until the mid 1970s.

Tin Fronts
One hundred all-Leyland PD2/12s were ordered for 1952-3 delivery by the Birmingham and Midland Motor Omnibus Company, better known by its informal title Midland Red, these were to have four-leaf electrically-powered platform doors and other new features, the most important of these cosmetically was that they were to conform to BMMO’s own-build double decks since 1946 (and most of Birmingham Corporation’s since 1949) in having a full width engine-bonnet concealing the radiator: at the time, following the press attention to couturier Christian Dior, such a structure, also used by Foden on its bus chassis from 1946 was called a ‘new look’ front; tradition-minded enthusiasts for buses more derisively dubbed such a structure the tin front. Leyland’s design for the Midland Red order was not a slavish copy of the BMMO design but had clear family resemblance, notably having a rounded void at the top of the twelve vertically oriented ventilation slots for the radiator which gave space for the BMMO monogram. These were to be the only PD2/12s to be built with this new front and also the only Leyland bodied Titan PD2/12s fitted from new with such a feature.

There were two facts which accounted for this, firstly when Leyland decided to offer the tin-front on general sale from 1953 it did so with a new set of variant suffixes and also in 1953, with effect by 1954, to the chagrin of many customers, Leyland decided to close its coachworks. two reasons for Leyland’s decision are adduced, firstly that coachbuilders (and not just in Farington) were prone to take industrial action with alacrity so the closure was to set an example to the rest of Leyland Motors’ workforce, secondly that Leyland needed the space to mass-produce lorry cabs with semi-skilled labour. Neither reason contradicts the other, but customers felt the lack of the Leyland body and outside coachbuilders, notably Metro Cammell Weymann, felt the benefit as their Lightweight Orion body was introduced during 1953, capturing the mood of the time, the initial range of Titans fitted with the full-width bonnet were as follows:

PD2/20 	Synchromesh 	Vacuum Brakes 	8ft wide. PD2/21 	Synchromesh		Air Brakes		8ft wide. PD2/22	Synchromesh 	Vacuum Brakes 	7ft 6in wide. PD2/23	Synchromesh		Air Brakes		7ft 6in wide.

It’s notable that Leyland’s two 1953 Titan demonstrators with manual gearboxes were both coded PD2/20 although the first, all-Leyland STC887, carried an exposed radiator, so perhaps should have been coded PD2/12. UTF930 on the other hand, had both the tin-front and the Orion Body; both were successful on their demonstration tours and later operated for a further 15 years with respectively Scout Motor Services of Preston and Yorkshire Woollen District Traction Company of Dewsbury.

The biggest order for the PD2/20, which was the biggest seller of the range, was from Edinburgh Corporation Transport, who took 300 with Orion bodies, from 1954-7 to bury their trams. A Baillie of Edinburgh city council(an honorary title for a senior councillor, roughly equivalent to an Alderman in England) famously described them unfavourably in the Edinburgh council chambers in the following paragraph of ringing rhetoric:

“They are ungainly, inelegant, monstrous masses of shivering tin. They are modern to the extent of being able to produce a perfect synchronisation of rock n’ roll.”

That said they outlasted the contemporary Alexander bodied Guy Arab IVs delivered in smaller quantities and some ran over twenty years in service, with the late survivors running for Lothian Regional Transport, Leyland used ECT fuel returns in the late 1950s in its advertising, ‘Scots find them thrifty’ was the headline over a greyscale plate of one, beside a large balloon caption which read “9.75 MPG! in daily service.”. They so much became fleet standard that the tin-front was replicated in glass reinforced plastic by ECT, and fitted to Guy Arab II and Daimler CV chassis, as well as a preceding batch of all-Leyland PD2/12s, even extending its use to ancillary vehicles such as gritting lorries converted from Arab III single deckers. When Leyland switched to a revised frontal appearance in 1960-61, (see below) Edinburgh stuck to their home built version of the BMMO outline, fitting the city Crest where the BMMO monogram had gone on their batch and thus later Edinburgh Titans are sometimes quoted in Leyland codes as having exposed radiators, a similar confusion attached to full-fronted Titans for a variety of operators.

Another large customer for the PD2/20 was Liverpool Corporation Transport Department who took 100 each over 1955/6 with Duple and Alexander bodies, It was also popular with the Scottish Bus Group, who dual-sourced taking lowbridge Titans with Alexander, Northern Counties and Park Royal bodies at the same time as taking Bristol-ECW LD6G Lodekkas, the only SBG subsidiary not to take Lowbridge PD2/20s being cash-strapped Highland Omnibuses, who did not purchase a new double decker until 1979, instead taking cascades from within the group and trawling the wider second-hand market for its double-deck requirement, which other than Inverness town services and school contracts was mainly required to transport the workforce to the Dounreay experimental nuclear facility. The most unusual coachbuilder on the PD2/20 was for Sheffield Transport, who added five with Eastern Coach Works bodies in 1957, ECW bodies, like Bristol Chassis were at the time restricted to wholly state-owned operators and Sheffield Transport although managed by Sheffield Corporation had three components: the wholly municipal A fleet; the half municipal, half British Railways owned B fleet and the wholly British Railways owned C-Fleet; it was for this unit that these five were built, with similar H32/28R bodies to the Bristol KSW buses of similar layout and dimensions used by BTC fleets and used on inter-urban services from Sheffield inherited from the London and North Eastern Railway.

Major PD2/21 customers included East Midland Motor Services and The North-Western Road Car Company. Blackpool took five in 1957, fitting them with rear-entrance H.V. Burlingham bodies with full width fronts but open rear-platform entrances.

Customers for the narrower PD2/22 version included Jersey Motor Transport, West Riding Automobile Company and the Corporations of Darwen, Great Yarmouth, Luton, and St Helens, the full-width front for the narrower chassis was made from standard components, the major difference being that the mudguards to the front wing assembly were narrower, narrow double deckers with air-brakes were very much a minority taste.

Having had a good reception at home and overseas for demonstrators with the Pneumocyclic gearbox, which built on the previous pre-selective epicyclic design by being of direct-acting semi-automatic engagement, thus removing the need for a change-speed pedal, and being adapted for fully-automatic control, although, being air-pressure operated it required an air-pressure braking system, Leyland launched four further variants to the tin-front Titan in 1954, two of which were specifically designed to suit the contemporary vogue for lightweight construction, these were all air-braked:

PD2/24	Normal Weight	Pneumocyclic	8ft wide. PD2/25	Normal Weight	Pneumocyclic	7ft 6in wide. PD2/26	Lightweight		Pneumocyclic	8ft wide. PD2/27 	Lightweight		Synchromesh		8ft wide.

Early rewards were substantial orders for Glasgow Corporation Transport, who were beginning the programme to replace their extensive tramway system, the much loved ‘caurs’. Glasgow had from 1951 standardised on epicyclic transmission and saw the Pneumocyclic as a significant advance and rewarded Leyland with their first post-war orders from Glasgow. These initially comprised 25 of the narrow PD2/25, which like contemporary AEC Regent V and Daimler CVG6 had Alexander bodies to Weymann outline. 300 wider PD2/24s followed, with Alexander-designed bodies, some of which were built by Glasgow Corporation in the Coplawhill car works, previously the centre of Glasgow tram overhaul, in the 1960s and 1970s it became the site of Glasgow’s Transport Museum and is now The Tramway Arts Centre. Some Pneumocyclic Titans had a centrifugal-clutch instead of a fluid-coupling to the transmission, this was apparently standard on the PD2/26 of which none are recorded as built. Blackpool took the PD2/27 in 1957-8 with full-fronted MCW lightweight Orion bodies. A further series of codes were raised late in 1954, presumably to extend lightweight features to the rest of the range, they were all synchromesh, but Leyland had as standard, removed synchromesh engagement from second gear, this only available as an option, due to excessive wear, which Leyland credited to driver-abuse, Halifax continued to specify synchromesh on second gear, to its last Titans in 1965, presumably at higher cost :

PD2/28	7ft 6in wide 	air-brakes PD2/30	8ft wide		vacuum brakes PD2/31	7ft 6in wide	vacuum brakes

Like the un-catalogued PD2/29, no PD2/28s were built, most of the customers for the PD2/21 continued with the PD2/31, familiar suspects including Luton, Lincoln, Darwen and Jersey Motor Transport. The largest customer for the PD2/30 was Central SMT (always the most cost-conscious of the Scottish Bus Group) who took 58 with a mixture of Northern Counties and Alexander L31/28R bodies between 1957-60.

The previous exposed radiator range still attracted profitable custom and unlike Daimler (last exposed-radiator CVG6 in 1953) Guy (last exposed-radiator Arab IV in 1959) and AEC (last exposed radiator Regent V in 1960) Leyland continued to offer the traditional option until the end of UK Titan production. So in late 1955, the type-codes were rationalised to include both frontal designs, to summarise as a table: Width/bonnet 	Pneumocyclic	Manual, air brakes	Manual, Vacuum brakes 8’ enclosed radiator	PD2/24	PD2/27	PD2/30 8’ exposed radiator	PD2/34	PD2/37	PD2/40 7’6” enclosed radiator	PD2/25	PD2/28	PD2/31 7’6” exposed radiator	PD2/35	PD2/38	PD2/41

Later OPD2s
Further OPD2 variants were added by 1954/5, these retained 17ft 6in wheelbase for 27ft 6in bodies, 8ft width and air brakes, they were: OPD2/6	Synchromesh	Enclosed radiator OPD2/7	Pneumocyclic	Enclosed radiator OPD2/9	Pneumocyclic	Exposed radiator OPD2/10	Synchromesh	Exposed radiator

CIE were the biggest customer, taking 218, three of which were experimental fully-automatic OPD2/9 and the rest OPD2/10 from 1955-7. CIE also took six special order OPD2/1s to 7ft 6in width during 1955, these being ordered to take the CIE bodies from a nine year old and utterly non-standard batch of Daimler CWA6.

Over 500 went to India in the first two years of production, notable among these were large batches of OPD2/9 for Bombay Electric Supply and Transport Company, previously a Daimler user, and subsequently standardised on Titans to this day.

Other customers were United Transport, Kenya (105), Madrid Corporation (50), and the Cape Tramways Group (28), other territories included Sierra Leone.

PD3
British construction and use regulations were further relaxed in July 1956, maximum double-deck length on two axles rose to 30ft and gross vehicle weight to 14 tons. Leyland immediately announced a six model range with 18ft 3in wheelbase, all for 8ft wide bodies, these were: PD3/1	Synchromesh	Air-Brakes	Full-Width bonnet PD3/2	Pneumocyclic	Air-Brakes	Full-Width bonnet PD3/3	Synchromesh	Vacuum Brakes	Full-Width bonnet PD3/4	Synchromesh	Air-Brakes	Exposed Radiator PD3/5	Pneumocyclic	Air-Brakes	Exposed Radiator PD3/6	Synchromesh	Vacuum Brakes	Exposed Radiator

Although there was never an OPD3, the thicker steel for the framing and the larger worm-wheel for the rear axle (as on the OPD2) were standard for the PD3, which was offered for export as well as the home market. Leyland exhibited the first completed example at the 1956 Commercial Motor Show. This had an MCW Orion body and although shown with 74 seats, it was reduced to a 68 seat layout before delivery to Potteries Motor Traction, who registered it 700AEH. It was a major constituent of the British Electric Traction Group’s new order programme for 1957, and was also ordered by Central and Western SMT and W. Alexander, all dual-sourcing with Lodekkas, taking batches of PD3/3 with 67-seat Lowbridge bodies until 1961. Municipal operators included Glasgow and Edinburgh, Glasgow taking one batch of 140 PD3/2 of which 25 were bodied by Glasgow themselves to Alexander design. These carried Albion Saltire shields on their Leyland badges as a public relations exercise, only the inner part of the badges was actually made in Glasgow. A number of independents also took the PD3 and the Ulster Transport Authority took examples with fully-fronted MCW bodies finished by the operator, some of these on PD3/5 chassis had the newly optional O:680 11.1 litre 150bhp engine and a luggage boot, for use on Belfast Airport services; some of the PD3/4s for rural routes also had a rear luggage boot, whilst the PD3/4s allocated to Derry City had the first instance of power-assisted steering on a Leyland Double-decker.

Larger customers for full-front Titans were Ribble and Southdown within BET, both of which took a mixture of PD3/4 and PD3/5 over 1957-63 and 1957-67 respectively. The O:680 was only available on Pneumocyclic Titans, the last customer being Leicester.

Initially the best export customer was CIE, taking 175 PD3/2 from 1959-61 to form the 74-seat operator-bodied RA class, the type running in Dublin until the late 1980s.

Later developments
During 1960 a new full-width bonnet was introduced, made of glass-reinforced plastic and with a sculpted nearside edge to improve kerb visibility for the driver, this became known as the St Helen’s Front after its first customer. The front grille was similar to Leyland and Albion Lorries of the time with the Motor Panels LAD cab. When this front was fitted an A was added to the type number, e.g. PD2A/28 or PD3A/2.

In 1962 Leyland de-listed the narrow PD2 versions, although 12 (described as special PD2/40) were completed for Warrington in 1965. In contrast during 1963 Ribble took its last 35 PD3/5 Titans with MCW bodies to the newly authorised width  of 8ft 2½in. Two vacuum braked short Titans remained listed, the PD2A/30 and the PD2/40, but with SBG customers switching to a new air-braked Leyland-Albion double decker, the Vacuum-braked PD3A/3 was discontinued after SBGs 1961 deliveries.

Glasgow’s last Titan was its only PD3A/2 and was shown at the 1961 Scottish Motor Show, alongside the low-height derivative of the Titan designed for the Scottish Bus Group, the Lowlander was designed at Albion but production versions were assembled in Glasgow from CKD kits supplied by Leyland, it used the front-end structure of the PD3A almost unmodified but had a complex swept-down frame allowing a step less forward entry. Three variants were built of four offered, all were air-braked and most had the GRP front. The exceptions were two full-fronted batches built for Ribble. In general those sold to SBG were badged Albion, and those sold in England were badged Leyland. Advances on the Lowlander only were an uprated “power-plus” O:600 developing 140bhp and a dual-circuit braking system. Air suspension was optional on the rear axle, which was of the drop-centre type

The last large order for vacuum braked Titans was from Edinburgh, who took 50 PD3/6 in 1964, the following year (presumably after completion of the narrow Warrington buses) all vacuum-braked Titans were discontinued.

Export sales continued unabated, Cape Tramways taking 185 PD3 with Pneumocyclic gearboxes in 1964/5, Kenya and Sierra Leone continued to take Titans; a final series of revisions to the range in 1967, brought many components in to line with the now larger-selling Atlantean, the main changes were a move to dual-circuit air brakes and the adoption of the Rationalised Pneumocyclic gearbox in semi-automatic Titans. This resulted in a change of nomenclature with A now denoting the new gearbox, regardless of front-end appearance.

PD2A/44	Short Rationalised Pneumocyclic	Plastic Front PD2/47	Short Synchromesh	Plastic Front PD2A/54	Short Rationalised Pneumocyclic	Traditional Radiator PD2/57	Short Synchromesh	Traditional Radiator PD3/11	Long Synchromesh	Plastic Front PD3A/12	Long Rationalised Pneumocyclic	Plastic Front PD3/14	Long Synchromesh	Traditional Radiator PD3A/15	Long Rationalised Pneumocyclic	Traditional Radiator

The final export territory was Indonesia who took a solitary PD3/11, whilst the last Titan delivered to the UK was an East Lancashire bodied PD3/14 ordered by Ramsbottom Corporation and delivered to SELNEC PTE in November 1969, registered TTE386H.

In 1969 the line was shipped to Ashok Leyland for continued production using Ashok-Leyland running units: a link to the current Ashok Leyland specification-sheet is included below.

Post-war Titans in London
After World War II, a batch of 65 standard Leyland-bodied PD1 were ordered, to provide a stop-gap until RT-type buses could be delivered in quantity, these arrived in 1946 and were numbered STD 112-76.

As part of the RT programme (see above) London Transport bought 2,131 Leyland Titans specifically designed for use in London. They were designated as the RTL (1,631 built) and the wider variant RTW (500 built). In appearance they were very similar to the AEC-built RTs (4,825 built), the radiator shell being the most obvious difference (aside from the greater width of the RTWs). The RTL carried Weymann, Metro-Cammell and Park Royal hardwood-framed bodies identical in outline to those on RTs, whilst the RTW carried Leyland steel-framed bodies.

All of the PD1s, the last of the STD class started in 1936, were exported in 1956 to Yugoslavia.

London Transport over-ordered the RT series, relying on overly optimistic projections of traffic growth, as a result many late RTs and RTLs were stored on delivery in 1953/4, entering service up to four years later to replace Trolleybuses and wartime RTs, as a result of this and the 1958 London Bus Strike and the ensuing service reductions LT decided to withdraw the standard RT series from 1958, RTLs went not only to independent operators, notably the A1 Service consortium in Scotland, Barton Transport and Stevenson’s of Uttoxeter but also to Jersey Motor Transport and Walsall Corporation. Most of the RTW’s went to the Ceylon Transport Board, the last RTW was signed-off London service in 1968 and the last RTW in 1966.

In 1963/4 London Transport purchased two batches of service-tenders for the London Underground, based on Leyland Titan PD3A/2 chassis; these carried crew-cabs by Sparshatt of Portsmouth and van bodies by Mann Egerton of Norwich, the first batch was registered 571-5EYU and the second ALM841-3B. . These were the last front-engined Leyland Titans bought by London Transport, although some PD2s and PD3s were used by private operators on tourist services in London in the 1970s and 1980s. London Transport were the single largest customer for PD series titans, but even they only took 15.6% which gives an indication of how widely and strongly the Titan sold.

In Service
The PD1 series were at least as reliable and durable as their pre-war counterparts but it was felt, particularly in Manchester, that an 8ft wide PD1 was underpowered. The combination of the constant–mesh gearbox and a relatively low-powered engine, with Leyland’s patented governor, did however make the timing of changes from second gear into third difficult. The timing chain on the E181 engine was difficult to maintain correctly, and unless the injectors were attended to regularly smoke emissions could be a problem, G.G. Hillditch suggests that there was an inherent air-induction problem with the engine. However it was more changing operational circumstances and operating policy than lack of reliability that saw most PD1s withdrawn in the early 1960s, although many were chosen for driver training because of their more challenging if basically abuse-proof gearboxes. Barton Transport were an interesting exception in that they withdrew the last of their 1947 PD1As in 1974, only a year later their last new double deckers, 1963 AEC Regent Vs, followed and their last double decker, a secondhand AEC Renown, was sold off in 1976.

The PD2’s, as alluded-to earlier, had the advantage of the renowned O:600 engine, during the 1950’s Leyland launched a transport-press advertising campaign stressing the mileage O:600 engines could achieve in Titans between full overhauls, quoting in 1956 a Warrington PD2/1 which had achieved 475,000 miles with only attention to the cylinder heads and fuel-injectors and regular oil-changes. One failing though was that the injector pressure pipes could crack and with no visible external sign feed fuel oil into the engine lubricating oil, this was combated by testing engine-oil viscosity regularly. It was one of the few areas where the O.600 was not as engineer-friendly as the AEC 9.6 litre.

The synchromesh gearbox had however early manufacturing problems such that Halifax Corporation had total gearbox failures in its first seven PD2/1s over a fortnight. A number of PD2s were thus fitted with PD1 type gearboxes during 1948 and 1949, a Leyland engineer acquainted with Geoffrey Hillditch described the early synchromesh gearboxes as ‘infamous’, down-changes on hills from third to second required very heavy pressure on the gearlever and some of these snapped. Early PD2s had the Metalastic spring bushes as fitted to the PD1A, but the PD2 chassis was some 5¼ cwt heavier and with post-war austerity easing and better-appointed bodies being specified, some of the PD2’s so fitted began to lean, so much so that Mr Hillditch recalls one taking the top off a gas-lamp standard in Halifax when pulling away from a stop, as the lowbridge body layout becoming fully laden had exacerbated this particular bus’ already-visible nearside list; copper/brass bushes were returned to and the 27ft and 30ft Titans had a rear suspension stabiliser arrangement. Later Leyland removed 2nd-gear synchromesh from the standard manual gearbox, and as the plates denoting which type of gearbox was fitted could be lost during overhaul, driver confusion ensued where both types were in use at once.

The steering was very heavy by modern standards; that said compared to the contemporary AEC Regent the Titan driver generally had a quieter and less vibratory workspace, the angled handbrake perhaps being less than ergonomic to use, and the very low ratio and lack of synchromesh on the crawler first forward gear made down-changes to it difficult: For the record the forward-ratios in the PD2 gearbox were top 1:1, 3rd 1.59:1, 2nd 2.63:1 and 1st 5:1.

The Pneumocyclic Titans were generally reliable but the lack of engine braking could lead to heavier brake lining wear and to driver mistrust. The centrifugal-clutch, where fitted, gave rough take-off and exacerbated both transmission and engine wear, in general, the brakes could fade easily if heavily used, a particular problem arose with the front-brakes of tin-front versions with either gearbox, leading to grilles for brake cooling being added.

In London both the heavy steering (although the entire steering assembly was sourced from AEC) the less-regular tick-over and subjectively less lively performance of the Leyland engine compared to its AEC equivalent made the RTL and RTW less popular with drivers where both makes were allocated to the same garage. Eighteen RTLs were moved to Country Area garages in 1959 but the threat of industrial action by crews saw them moved back to the red bus area.

At Aldenham, not only did the RTW’s have to exchange their Leyland bodies between themselves for obvious reasons of width Metro Cammell used a different body mounting to Park Royal Vehicles and Weymann, as a result the Metro-Cammell bodied RTLs were obliged to swap-bodies with others of the batch on overhaul. The other RTLs could and did receive RT10 and RT8 type bodies originally mounted on Regents by the other two firms, including examples with roof-mounted front route-number boxes, only originally fitted to RTL 501, the only reason for them not having Saunders-Roe or Craven bodies was that these were not adapted to clear the offside dumb-iron on the RTL chassis. The RTLs and RTWs which had undertaken overseas tours were kept with the same bodies they had whilst touring, probably out of sentiment, as the same was done with ‘tourist’ RTs, all of this select band ran with GB plates on the rear panel until the end of their service in London.

Into the 1960s and 1970s traffic-department pressure, especially after driver-operation of double decks was legalised in 1966, led to later PD2s and PD3s despite their mechanical durability not seeing-out a full service life, the Transport Act 1968, with its provisions for a new bus grant scheme, allowing only double-deck buses with an extreme front entrance, exacerbating this, and forming an effective end to UK-market Titan orders. Even so, in 1971-2, National Bus Company subsidiary Northern General Transport were allowed to rebuild 1957 Titan PD3/4 NNL34, delivered to Tyneside Tramways with an MCW H72R body, as a 68 seat H39/29D two-doorway normal-control double decker, the dual-stream exit mounted directly behind the single-stream entry but separate from it, the entry directly facing the driver-operator enabling both a front-engine and driver operation without the contortions required of the driver in the few unsatisfactory adaptations of half-cabs to one-man-operation, as it was termed at the time. MCN30K, the Tynesider, was fitted with a Routemaster-style GRP bonnet and is now preserved awaiting restoration, it remains unique as the only normal-control Titan. It received the chassis designation Leyland/NGT 3000, the new chassis number matching its fleet number.

Even regarding the aforesaid, as late as 1979, Geoffrey Hillditch, by then General Manager at Leicester City Transport, could cite lower operating-costs in maintenance and fuel-consumption as a reason for retaining his last PD3s on busy services, producing in A Further Look At Buses maintenance records selected from two buses (PD3A/1 number 70 and PD3A/12 no 20) at random to prove his point.

That said, the Titan was not around in significant numbers from late 1986 to attract the attention of operators looking to re-introduce open-boarding and conductor-operation, notably Stagecoach having two late Leyland Titans from Leicester as part of its Perth fleet in January of that year, but chose more readily available former LT Routemasters for its Magic Bus operation in Glasgow, as did Kelvin Scottish and Clydeside Scottish in a notable feature of the Glasgow bus wars.

afterlife
A representative collection of post-war Leyland Titans from early PD1s to the last-built PD3/14 survives in preservation, not only in the UK but also in Australia, Spain, the USA, South Africa and a number of other new and secondhand export territories. Some of these are in passenger-carrying order and can be ridden-on at rallies or museum running days.

Until the rules changed in the 1990s drivers who wanted a PSV licence enabling them to drive a double-deck bus had to train and test on one, there was a similar restriction on manual-gearbox PSVs so that manual-gearbox Titans and similar double-deck types had a premium in driver training which allowed a larger number of them to survive despite the 1968 Act provisions. A few PD2 and PD3 Titans continue in revenue-earning service, in the UK and across the world, most as heritage hire buses, some as mobile showrooms and some as open-top tourist-buses but at least one has been converted into a 12-berth mobile hotel.

Another common use for PD2 and PD3 Titans sold out of PSV service was as playbuses.

A major export territory for secondhand Titans was Hong Kong, where China Motor Bus took over 100 full-front examples from Southdown (PD3/5) and Ribble (PD3/4) in the early 1970s, most of the Southdown examples were converted to both half-cab layout and Gardner 6LX engines, in rebuilt form resembling CMB’s standard Guy Arab V, but the largest customer for second-hand British Titans was Sri Lanka, who took the vast majority of the London RTW class. Yugoslavia took all of London Transport’s 65 PD1s in 1956

One of the first Titan PD1s to be exported at the end of a UK service life was a Beadle bodied PD1/1 new to City Coach Company, converted to open-top by successor Eastern National and used from 1966 on a tourist operation in the USA, the first of many Titans sold for similar use to North America.

some quirks
In 1946 Isle of Man Road Services put its first all-Leyland Titan PD1 into service, it did this despite Tynwald only authorising a maximum capacity of 34 seats on buses outside the Douglas Corporation area. Until the law was revised in 1947 IoMRS ran it with all but the rearmost 8 seats on the upper-deck sealed off. When the law changed a further 11 all-Leyland PD1 arrived, all of which operated as 56 seaters (Jack p152) as then did their forerunner, IoMRS bought new and secondhand Titans until 1974 and its successor Isle of Man National Transport ran them as its standard double decker until from 1978 secondhand Atlanteans replaced them.

In 1963-7 Preston Corporation converted some 1951 and 1952 PD2/10s from 27ft by 7ft 6ins rear open platform to 30ft by 8ft forward entrance, using and heavily modifying the original standard Leyland bodies in the process, some of which were converted from Lowbridge to Highbridge during the extension process. Doncaster Corporation re-used relatively new trolleybus bodies by C.H. Roe on some PD2/1s and new PD2/40s (and Daimler CVG6s) in 1962 after moving to an all-diesel fleet. Warrington Corporation and Barton Transport were unusual in having some of their early PD1s initially fitted with bodies they had bought earlier, Warrington’s Metro-Cammell from pre-war Titans, and Barton’s Duple from some of the TD1s they had rebodied in the first years of hostilities, a tell-tale on both of these was that the cab projected slightly forward from the line of the body, whilst the Doncaster PD2/1s with re-used bodies had an overhanging ledge above the cab.

There were three well-known instances of non-standard powerplants in the 1950s, firstly as part of the PDR1 development programme Leyland bought a TD6c from Birmingham in 1952 and refitted it with a turbocharged O:350 5.7 litre engine driving through a pre-selective gearbox, in such form it was lent to Edinburgh Corporation for trials. In 1955 Isaac Hutchison of Overtown, Lanarkshire had a PD2/20 with an E181 7.4 litre engine and constant-mesh transmission, as fitted to the PD1, and in 1957 North Western Road Car Company operated one of its PD2/27s with a Ruston & Hornsby air-cooled engine. Although without publicity Midland Red experimentally fitted its own diesel engines into one or two of its PD2/12s.

West Monmouthshire Omnibus Board took a single Leyland PD2/37 in 1957 and fitted it with a single-deck Willowbrook B31F body, for use on the mountainous Bargoed Hill route, an additional feature was a sprag-gear to prevent run-back on hills. When the route was revised in the early 1960s to take less steep gradients the bus had its sprag-gear removed and was re-bodied as a lowbridge double-decker by Massey Brothers of Wigan, as a double decker it survived post Local Government re-organisation in 1974 to run for Islwyn Borough Transport.

In Conclusion
It was claimed at the end of UK Titan production that the only component shared between the first TD1 and the last PD3/14 was the Leyland badge on the radiator, but the screws fixing it were of a different specification. 14,057 Titans were sold in the UK between 1946 and 1969 and it was the best selling double-deck bus in 1946, 1947, 1949, 1950, 1954-9 inclusive and 1961.