British United Traction

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British United Traction
Industry Bus manufacturing
Founded1946
Defunct1964
Owner AEC
Leyland

British United Traction (BUT) was a manufacturer of railway equipment and trolleybuses. It was established in 1946 as a joint venture between AEC and Leyland.

Contents

History

Historical BUT trolleybus #101 in Arnhem Arnhem-101.1.jpg
Historical BUT trolleybus #101 in Arnhem

British United Traction was established in 1946 when AEC and Leyland amalgamated their trolleybus interests. Neither had produced trolleybuses since the early years of World War II. With both forecasting that demand would return to pre-war levels as networks began to close, a joint venture was formed. The new company was organised so that AEC would design and produce vehicles for the UK market while Leyland looked after export markets, although there were some exceptions to this. The only noticeable difference between the manufacturers' output was the wheels. [1] [2] [3]

Initially vehicles were produced at Leyland's Ham, London factory, with the first vehicles completed in 1947 for Johannesburg. After the factory closed 1948, production moved to AEC's Southall and Leyland's Leyland, Lancashire factories. Following AEC's acquisition of Crossley Motors, AEC transferred its production to the latter's Stockport factory. Trolleybus production wound down in the late 1950s, however a final batch for Wellington was built at Scammell's, Watford factory in 1964. [1] [2] [3]

Trolleybuses

Diesel engines for railways

British United Traction was a major supplier of diesel engines for British Rail's first-generation diesel multiple units. These engines were built in 125 hp (93 kW) or 150 hp (110 kW) versions and were branded BUT, although manufactured by BUT's parent companies, AEC and Leyland. There was also a 230 hp (170 kW) BUT engine, manufactured by Albion, a Leyland subsidiary.

A 275 hp (205 kW) version was supplied to the Ulster Transport Authority for its UTA MPD class railcar.

BUT / ACV railcars

BUT / ACV railcars
In service1952–1960
ManufacturerBritish United Traction
Associated Commercial Vehicles (AEC, Park Royal Vehicles)
Order no.
List
  • 30128 (DMT+TT+DMBT, 79740-79742)
  • 30174 (DMBT, 79743-79744)
  • 30175 (DMT, 79745)
  • 30176 (TT, 79746-79747)
  • 30214 (DMS, 79748)
  • 30215 (TS, 79749)
  • 30216 (DMBS, 79750)
Family name First generation
ReplacedSteam locomotives and carriages
Constructed1952, 1955–1957
Scrapped1963
Number built3 DMT/DMS, 4 DMBT/DMBS, 4 TT/TS [a]
Number scrappedAll
Formation1-, 2-, or 3-car sets
CapacityDMT/DMS: 41 (prototype car), 34 (production cars)
DMBT/DMBS: 28
TT/TS: 48
Operators British Rail
Depots Watford
Specifications
Car length37 ft 6 in (11.43 m)
Width9 ft 0 in (2.74 m)
Height11 ft 4 in (3.45 m)
Wheelbase 22 ft 0 in (6.71 m)
Maximum speed45 mph (72 km/h)
Weight15 long tons (15 t) (motor cars),
10.5 long tons (10.7 t) (trailers) [4]
Prime mover(s) AEC 6-cylinder diesel, one per motor car
Power output125 bhp (93 kW) each engine
TransmissionMechanical: 4-speed epicyclic gearbox
Coupling system Screw-link couplings
Track gauge 4 ft 8+12 in (1,435 mm)

In 1952, British United Traction introduced a prototype diesel-mechanical multiple unit as a demonstrator. This was followed by orders for production units built from 1955 to 1957. The units were designed by BUT and constructed by Associated Commercial Vehicles group companies, with underframes and engines by AEC and bodies by Park Royal Vehicles. Instead of bogies, each vehicle had a two-axle four-wheel arrangement. The demonstrator unit was introduced as a 3-car set with two motor cars and a centre trailer car. In addition to operating as either a 3 or 2-car set, each motor car was equipped with driving controls at both ends and could operate as single-car units, with a similar configuration to the later British Rail railbuses. [5]

Operations

The demonstrator unit underwent a series of trials across all regions of British Railways, often on low revenue routes. The first trials were operated between Didcot and Newbury, followed by trials on High Wycombe-Princes Risborough, Epping-Ongar, [6] Watford-St Albans, Chalfont & Latimer-Chesham, Bangor-Amlwch, [7] Ayr-Dalmellington, [8] Hull-South Howden, Birmingham-Solihull, Gravesend-Allhallows-on-Sea, [9] Wellingborough-Higham Ferrers and Harrow-Belmont services.

BR acquired the set in 1955, together with a second 3-car set and a spare motor car and trailer. Under BR ownership, these units worked on regular Watford-St Albans services. A third 3-car set was delivered in 1957 and operations were expanded to include regular Harrow-Belmont services.

Withdrawal

The units were unreliable in regular service, and were noted for their poor ride quality. By 1961, all vehicles had been moved to Derby Friargate for storage. No other use could be found for them, and all units were subsequently withdrawn and scrapped at Derby C&W Works by 1963. [10]

Fleet details

Table of orders and numbers
Lot No.Type [a] Diagram [b] QtyFleet numbersNotes
30128Driving Motor Third (DMT)50017974041 seats
30128Trailer Third (TT)50017974148 seats
30128Driving Motor Brake Third (DMBT)50017974228 seats
30174Driving Motor Brake Third (DMBT)506279743-7974428 seats
30175Driving Motor Third (DMT)50617974534 seats
30176Trailer Third (TT)506279746-7974748 seats
30214Driving Motor Second (DMS)50617974834 seats
30215Trailer Second (TS)50617974948 seats
30216Driving Motor Brake Second (DMBS)50617975028 seats

Notes

  1. 1 2 Third Class (T) was renamed Second Class (S) in 1956.
  2. Diagram numbers apply to 3-car sets, not individual cars.

References

  1. 1 2 Jack, Doug (1977). The Leyland Bus. Glossop: The Transport Publishing Company. pp. 295–299. ISBN   090383913X.
  2. 1 2 Companion to Road Passenger Transport History. Walsall: Roads & Road Transport History Association. 2013. p. 102. ISBN   9780955287633.
  3. 1 2 Lockwood, Stephen (2017). A-Z of British Trolleybuses. Marlborough: Crowood Press. ISBN   9781785002885.
  4. The ABC of British Railways Locomotives, Combined Volume (Summer 1959 ed.). Ian Allan. p. 221-222.
  5. Stuart, Eric (November 2015). "The ACV lightweight diesel trains". BackTrack . Vol. 29, no. 11. Pendragon Publishing. p. 688-690.
  6. Stuart, Eric (November 2021). "The last days of steam on the Central Line". Steam Days. No. 387. Mortons Media Group. p. 29.
  7. "Lein Amlwch (Anglesey Central Railway Ltd): History".
  8. "Railway Notes: Scottish Tidings". Meccano Magazine . Vol. 38, no. 8. August 1953. p. 407.
  9. "Southern Railway E-Mail Group: A.C.V. Lightweight Diesel Railcar".
  10. "ACV / BUT Operations".

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