The British Rail Class 84 was a 25 kV AC electric locomotive that operated on the West Coast Main Line (WCML) of the London Midland Region.

British Railways AL4
British Rail Class 84
Preserved locomotive 84001 on display at Crewe Works open day on 11 September 2005
Type and origin
Power typeElectric
BuilderNorth British Locomotive Company
Order numberL91[1]
Build date1960–1961
Total produced10
Specifications
Configuration:
 • AARB-B
 • UICBo′Bo′
 • CommonwealthBo-Bo
Gauge4 ft 8+12 in (1,435 mm) standard gauge
Wheel diameter4 ft 0 in (1.219 m)[2]
Wheelbase39 ft 6 in (12.04 m)[2]
Length:
 • Over beams53 ft 6+12 in (16.32 m)[2]
Width8 ft 8+14 in (2.648 m)[2]
Height:
 • Pantograph13 ft 0+916 in (3.977 m)[2]
 • Body height12 ft 4+14 in (3.766 m)[2]
Loco weight76.60 long tons (77.83 t; 85.79 short tons)
Electric system/s25 kV AC Catenary
Current pickup(s)Pantograph
Traction motors4 × GEC WT501[3]
Gear ratio25:74[3]
Train heatingElectric Train Heating
Train brakesVacuum; Dual from 1972[1]
Performance figures
Maximum speed100 mph (160 km/h)
Power output:
 • 1 hour4 × 890 hp (660 kW)[3]
 • Continuous4 × 750 hp (560 kW)[3]
Tractive effort50,000 lbf (220 kN)
Brakeforce65.5 long tons-force (653 kN)
Career
OperatorsBritish Rail
NumbersE3036–E3045; later 84001–84010
Axle load classRoute availability 6
Retired1979–1980
DispositionOne preserved, remainder scrapped

The ten strong class was one of five prototype classes of electric locomotives built in the early stages of WCML electrification. Built between 1960 and 1961, the type was not a success, as they were beset by technical problems, and after several lengthy periods of storage, and unsuccessful attempts at resolving these problems, British Rail decided to withdraw the entire fleet between 1977 and 1980.

History

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As part of the modernisation of the West Coast Main Line, which included electrification, 100 locomotives of five types were acquired from different manufacturers. Ten Class AL4 locomotives numbered E3036 - E3045 were built in 1960 by the North British Locomotive Company in Springburn, Glasgow, to a design by GEC.[4]

Locomotive E3040 worked the inaugural AC electric-hauled train from Manchester Piccadilly to Crewe on 12 September 1960.[2]

Power supply

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The locomotives always worked on power provided by overhead catenary energised at 25,000 V AC. However, the main transformer, normally operated with the four windings in series, could be operated at 6250V AC with the transformer windings in parallel. This voltage was initially to be used where limited clearances gave concern over use of the higher voltage. Since the clearances were found to be adequate, the lower voltage connections were locked out of use.[5]

Service

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Once in service a number of problems emerged with the class, including rough riding, flashovers in the transformer windings, short lifespans for the motor spring drives, and major problems with the mercury-arc rectifiers. In April 1963 the entire fleet was temporarily taken out of service, and was returned to GEC Dukinfield, the builder of the electrical equipment, in an attempt to find a solution, and remedial work was carried out.[6][7]

When the class returned to service, the problems persisted, and in 1967 they were placed into storage, using the former steam shed at Bury,[8] along with Class AL3.[9] During this time E3043 went to Rugby Testing Centre for trials.[10]

Reprieve and rebuilding

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The persistent problems could have been the end of the ten locomotives of Class 84, but the extension of the West Coast Main Line electrification to Glasgow meant that more electric locomotives would be needed. It was therefore decided that the stored Class AL3 and AL4 locomotives would be repaired, and returned to service which was conducted at Doncaster.[10]

After spending five years in storage, all ten locomotives were rebuilt with silicon rectifiers and dual brakes in 1972.[1][11] and were reclassified under TOPS as Class 84, being renumbered 84001 - 84010.

Withdrawal

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The second rebuild overcame some of the previous problems, however new problems emerged involving traction motor failures, caused in part by the long period they had spent in storage, and the class continued to give trouble in service. By the mid-1970s, having already spent a substantial amount of money on them, British Rail could not justify any further investment in the fleet, especially since the recently introduced Class 87s allowed them to be sidelined. The decision was taken to withdraw them from service, with 84005 and 84007 being the first to be withdrawn in April 1977, the last to be withdrawn were 84003 and 84010 in 1980.[6][7][12]

After withdrawal

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ADB968021 (ex 84009) load bank tester (1987)

Several of the locomotives were saved from scrap: 84001 was donated to the National Railway Museum for preservation. 84002 and 84010 were returned to GEC for a proposed scheme to use them as new-technology test bed locomotives, however this project never materialised, and both were scrapped in December 1982.[12]

84009 saw further use in a new guise; it passed to the British Rail Research Division, and was rebuilt as an unpowered mobile load bank tester, to test the power supply to new and upgraded overhead line equipment, and was renumbered as ADB968021. In 1992 it was withdrawn from service and broken up.[6] 84003, was saved to be used as a source of spares for 84009 and for possible conversion to departmental use, but was scrapped in 1986.[12]

Preservation

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One locomotive (84001) has been preserved by the National Railway Museum: This was initially meant to be temporary; the locomotive was to be exchanged at a later date for a more representative example of WCML electric traction such as a Class 86 or Class 87.[12] It was later on loan to the Scottish Railway Museum, Bo'ness.[13]

Fleet details

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Key: Preserved Scrapped
Numbers[1] Date Introduced[1] Withdrawn[14][15] Disposal
Pre-TOPS TOPS NBL Works No.
E3036 84001 27793 March 1960 22 January 1979[1] Preserved by the National Railway Museum.[13]
E3037 84002 27794 May 1960 September 1980 Scrapped at Texas Metals
E3038 84003 27795 June 1960 November 1980 To Research Department
Scrapped at Vic Berry, Leicester
E3039 84004 27796 July 1960 12 November 1977[1] Scrapped at Birds, Long Marston
E3040 84005 27797 August 1960 20 April 1977[1] Scrapped at Birds, Long Marston
E3041 84006 27798 October 1960 January 1978 Scrapped by J Cashmore at Crewe Yard
E3042 84007 27799 October 1960 April 1977 Scrapped by J Cashmore at Crewe Yard
E3043 84008 27800 December 1960 October 1979 Scrapped at Crewe Works
E3044 84009 27801 December 1960 3 August 1978[1] To Research Department
Scrapped at Gwent Demolition, Margam
E3045 84010 27802 March 1961 November 1980 Scrapped at Texas Metals

References

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  1. ^ a b c d e f g h i Webb & Duncan 1979, p. 59
  2. ^ a b c d e f g Webb & Duncan 1979, p. 58
  3. ^ a b c d Webb & Duncan 1979, p. 54
  4. ^ Marsden & Fenn 2001, p. 82
  5. ^ Allan 1968, p. 11.
  6. ^ a b c Marsden, Colin J. (2007). The AC Electrics. Ian Allan Publishing Ltd. pp. 38–41. ISBN 978-0-86093-614-5.
  7. ^ a b Morrison, Colin (2014). AC Electric Locomotives. Ian Allan Publishing Ltd. pp. 16–18. ISBN 978-0-7110-3505-8.
  8. ^ Railway World December 1967, p. 554.
  9. ^ Longhurst 1979, Class AL4–84
  10. ^ a b Marsden & Fenn 2001, p. 83
  11. ^ Webb & Duncan 1979, p. 55
  12. ^ a b c d "Class History - AL4 / 84". The AC Locomotive Group. Archived from the original on 29 January 2023. Retrieved 29 January 2023.
  13. ^ a b @RailwayMuseum (26 January 2023). "Class 84, 84001, made the short trip from Holgate Engineering Works to the NRM via platform 11" (Tweet) – via Twitter.
  14. ^ "The Class 84 Fleet". Rail Blue. Archived from the original on 3 July 2016. Retrieved 11 February 2016.
  15. ^ "Class 84". RAIL. No. 88. EMAP National Publications. January 1989. p. 42. ISSN 0953-4563. OCLC 49953699.

Sources

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  • Longhurst, Roly (1979). Electric Locomotives of the West Coast Main Line. Truro: D. Bradford Barton Ltd. ISBN 0851533558. OCLC 16491712.
  • Marsden, Colin J.; Fenn, Graham B. (2001). British Rail Main Line Electric Locomotives (2nd ed.). Oxford Publishing Co. ISBN 9780860935599. OCLC 48532553.
  • Webb, Brian; Duncan, John (1979). AC Electric Locomotives of British Rail. David & Charles. ISBN 9780715376638. OCLC 6916046.
  • "British Railways Motive Power Survey". British Rail Locomotives and other motive power: Combined volume. London: Ian Allan. 1968. ISBN 0-7110-0008-5.

Further reading

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  • Derrick, Kevin (2014). Looking back at AC Electric Locomotives. Strathwood. ISBN 9781905276516. OCLC 931820979.
  • McManus, Michael. Ultimate Allocations, British Railways Locomotives 1948 - 1968. Wirral. Michael McManus.
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