View source for British Rail Class 84

{{Use dmy dates|date=January 2017}}
{{Use British English|date=January 2017}}
{{Infobox Locomotive
|name = British Railways AL4<br>British Rail Class 84
|powertype = Electric
|image = 84001 at Crewe Works.JPG
|caption = Preserved locomotive 84001 on display at [[Crewe Works]] open day on 11 September 2005
|builder =  [[North British Locomotive Company]]  
| ordernumber      = L91<ref name=WebbDuncan59>{{harvnb|Webb|Duncan|1979|p=59}}</ref>
|totalproduction = 10 
|builddate = 1960–1961 
|gauge = {{Track gauge|ussg|allk=on}}
|wheeldiameter = {{convert|4|ft|0|in|m|3|abbr=on}}<ref name=WebbDuncan58>{{harvnb|Webb|Duncan|1979|p=58}}</ref>
|wheelbase = {{convert|39|ft|6|in|abbr=on}}<ref name=WebbDuncan58 />
|tractionmotors = 4 × [[General Electric Company plc|GEC]] WT501<ref name=WebbDuncan54>{{harvnb|Webb|Duncan|1979|p=54}}</ref>
|poweroutput 1 hr = 4 × {{convert|890|hp|abbr=on}}<ref name=WebbDuncan54 />
|poweroutput cont = 4 × {{convert|750|hp|abbr=on}}<ref name=WebbDuncan54 />
| transmission = 
|gear ratio = 25:74<ref name=WebbDuncan54 />
|electricsystem = [[25 kV AC]] [[Overhead line|Catenary]]
|collectionmethod = [[Pantograph (rail)|Pantograph]]
|Britishclass = [[Bo-Bo]]
|aarwheels = [[AAR wheel arrangement|B-B]]
|uicclass = Bo′Bo′
|trainbrakes = [[Vacuum brake|Vacuum]]; [[Vacuum brake#Dual brakes|Dual]] from 1972<ref name=WebbDuncan59 />    
|locobrakeforce = {{convert|65.5|LTf|kN|abbr=on|lk=in}}
|over bufferbeams =  {{convert|53|ft|6+1/2|in|m|2|abbr=on}}<ref name=WebbDuncan58 />  
|width = {{convert|8|ft|8+1/4|in|abbr=on}}<ref name=WebbDuncan58 />   
|height = 
|bodyonly = {{convert|12|ft|4+1/4|in|abbr=on}}<ref name=WebbDuncan58 /> 
|pantodown = {{convert|13|ft|0+9/16|in|abbr=on}}<ref name=WebbDuncan58 />    
|locoweight = {{convert|76.60|LT|t ST}}   
|maxspeed = {{convert|100|mph|abbr=on}}    
|poweroutput = {{convert|3100|hp|abbr=on|lk=on}}
|tractiveeffort = {{convert|50000|lbf|kN|abbr=on|lk=on}}
|trainheating = [[Electric Train Heating]]
|operator = [[British Rail]]
|fleetnumbers = E3036–E3045; later 84001–84010
|axleloadclass = [[Route availability]] 6
|retiredate = 1979–1980
|disposition = One preserved, remainder scrapped
}}

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]].

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 ==
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 [[General Electric Company plc|GEC]].<ref name=MarsdenFenn82>{{harvnb|Marsden|Fenn|2001|p=82}}</ref>

Locomotive E3040 worked the inaugural AC electric-hauled train from [[Manchester Piccadilly station|Manchester Piccadilly]] to [[Crewe railway station|Crewe]] on 12 September 1960.<ref name=WebbDuncan58 />

== Power supply ==
The locomotives always worked on power provided by [[Overhead line|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 [[Structure gauge|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.{{sfn|Allan|1968|p=11}}

== Service ==

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 rectifier|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.<ref name="Marsden">{{cite book |last1=Marsden |first1=Colin J. |title=The AC Electrics |date=2007 |publisher=Ian Allan Publishing Ltd |isbn=978-0-86093-614-5 |pages=38–41}}</ref><ref name="Morrison">{{cite book |last1=Morrison |first1=Colin |title=AC Electric Locomotives |date=2014 |publisher=Ian Allan Publishing Ltd |isbn=978-0-7110-3505-8 |pages=16–18}}</ref>

When the class returned to service, the problems persisted, and in 1967 they were placed into storage, using the former steam shed at Bury,<ref>''Railway World'' December 1967, p. 554.</ref> along with [[British Rail Class 83|Class AL3]].<ref name=Longhurst>{{harvnb|Longhurst|1979|loc=Class AL4–84}}</ref> During this time E3043 went to [[Rugby Testing Centre]] for trials.<ref name=MarsdenFenn83>{{harvnb|Marsden|Fenn|2001|p=83}}</ref>

=== Reprieve and rebuilding===

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 [[British Rail Class 83|Class AL3]] and AL4 locomotives would be repaired, and returned to service which was conducted at [[Doncaster]].<ref name=MarsdenFenn83 />

After spending five years in storage, all ten locomotives were rebuilt with [[silicon rectifiers]] and dual brakes in 1972.<ref name=WebbDuncan59 /><ref name=WebbDuncan55>{{harvnb|Webb|Duncan|1979|p=55}}</ref> and were reclassified under [[TOPS]] as Class 84, being renumbered 84001 - 84010.

== Withdrawal ==

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 [[British Rail Class 87|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.<ref name="Marsden"/><ref name="Morrison"/><ref name="ACLG">{{cite web |title=Class History - AL4 / 84 |url=https://www.aclocogroup.co.uk/index.php/history-introduction/class-history-al4-84 |publisher=The AC Locomotive Group |access-date=29 January 2023 |archive-date=29 January 2023 |archive-url=https://web.archive.org/web/20230129114227/https://www.aclocogroup.co.uk/index.php/history-introduction/class-history-al4-84 |url-status=dead }}</ref>

== After withdrawal ==
[[File:19870830-BritishRail ADB968021.jpg|thumb|right|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.<ref name="ACLG"/>

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.<ref name="Marsden"/> 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.<ref name="ACLG"/>

== Preservation ==
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 {{brc|86}} or {{brc|87}}.<ref name="ACLG"/> It was later on loan to the Scottish Railway Museum, Bo'ness.<ref name="BonessReturn"/>

== Fleet details ==
{| class="wikitable"
!Key:
|bgcolor=#87cefa|Preserved
|bgcolor=#cecece|Scrapped
|}
{| class="wikitable"
|- 
!colspan=3|Numbers<ref name=WebbDuncan59 />
!rowspan=2|Date Introduced<ref name=WebbDuncan59 />
!rowspan=2|Withdrawn<ref>{{cite web|url=http://www.railblue.com/Fleet/class_84_fleet.htm|title=The Class 84 Fleet|work=Rail Blue|access-date=11 February 2016|archive-date=3 July 2016|archive-url=https://web.archive.org/web/20160703082731/http://www.railblue.com/Fleet/class_84_fleet.htm|url-status=dead}}</ref><ref>{{cite magazine|title=Class 84|page=42|issue=88|date=January 1989|magazine=[[RAIL (magazine)|RAIL]]|publisher=EMAP National Publications|issn=0953-4563|oclc=49953699}}</ref>
!align=left rowspan=2|Disposal
|-
!<small>Pre-TOPS</small>
!TOPS
!NBL Works No.
|-
|align=center bgcolor=87cefa|E3036
|align=center bgcolor=87cefa|84001
|align=center bgcolor=87cefa|27793
|align=center bgcolor=87cefa|March 1960
|align=center bgcolor=87cefa|22 January 1979<ref name=WebbDuncan59 />
|bgcolor=87cefa|Preserved by the National Railway Museum.<ref name="BonessReturn">{{cite tweet |user=RailwayMuseum |number=1618583911118041090 |title=Class 84, 84001, made the short trip from Holgate Engineering Works to the NRM via platform 11. |date=26 January 2023}}</ref><br>
|-
|align=center bgcolor=cecece|E3037
|align=center bgcolor=cecece|84002
|align=center bgcolor=cecece|27794
|align=center bgcolor=cecece|May 1960
|align=center bgcolor=cecece|September 1980
|bgcolor=cecece|Scrapped at Texas Metals
|-
|align=center bgcolor=cecece|E3038
|align=center bgcolor=cecece|84003
|align=center bgcolor=cecece|27795
|align=center bgcolor=cecece|June 1960
|align=center bgcolor=cecece|November 1980
|bgcolor=cecece|To Research Department<br>Scrapped at Vic Berry, Leicester
|-
|align=center bgcolor=cecece|E3039
|align=center bgcolor=cecece|84004
|align=center bgcolor=cecece|27796
|align=center bgcolor=cecece|July 1960
|align=center bgcolor=cecece|12 November 1977<ref name=WebbDuncan59 />
|bgcolor=cecece|Scrapped at Birds, Long Marston
|-
|align=center bgcolor=cecece|E3040
|align=center bgcolor=cecece|84005
|align=center bgcolor=cecece|27797
|align=center bgcolor=cecece|August 1960
|align=center bgcolor=cecece|20 April 1977<ref name=WebbDuncan59 />
|bgcolor=cecece|Scrapped at Birds, Long Marston
|-
|align=center bgcolor=cecece|E3041
|align=center bgcolor=cecece|84006
|align=center bgcolor=cecece|27798
|align=center bgcolor=cecece|October 1960
|align=center bgcolor=cecece|January 1978
|bgcolor=cecece|Scrapped by [[John Cashmore Ltd|J Cashmore]] at Crewe Yard
|-
|align=center bgcolor=cecece|E3042
|align=center bgcolor=cecece|84007
|align=center bgcolor=cecece|27799
|align=center bgcolor=cecece|October 1960
|align=center bgcolor=cecece|April 1977
|bgcolor=cecece|Scrapped by [[John Cashmore Ltd|J Cashmore]] at Crewe Yard
|-
|align=center bgcolor=cecece|E3043
|align=center bgcolor=cecece|84008
|align=center bgcolor=cecece|27800
|align=center bgcolor=cecece|December 1960
|align=center bgcolor=cecece|October 1979
|bgcolor=cecece|Scrapped at Crewe Works
|-
|align=center bgcolor=cecece|E3044
|align=center bgcolor=cecece|84009
|align=center bgcolor=cecece|27801
|align=center bgcolor=cecece|December 1960
|align=center bgcolor=cecece|3 August 1978<ref name=WebbDuncan59 />
|bgcolor=cecece|To Research Department<br>Scrapped at Gwent Demolition, Margam
|-
|align=center bgcolor=cecece|E3045
|align=center bgcolor=cecece|84010
|align=center bgcolor=cecece|27802
|align=center bgcolor=cecece|March 1961
|align=center bgcolor=cecece|November 1980
|bgcolor=cecece|Scrapped at Texas Metals
|-
|}

==References==
{{reflist|30em}}

===Sources===
*{{cite book|title=Electric Locomotives of the West Coast Main Line|first=Roly|last=Longhurst|publisher=D. Bradford Barton Ltd.|location=Truro|year=1979|isbn=0851533558|oclc=16491712}}
*{{cite book|title=British Rail Main Line Electric Locomotives|first1=Colin J.|last1=Marsden|first2=Graham B.|last2=Fenn|publisher=Oxford Publishing Co.|year=2001|edition=2nd|isbn=9780860935599|oclc=48532553}}
*{{cite book|first1=Brian|last1=Webb|first2=John|last2=Duncan|title=AC Electric Locomotives of British Rail|publisher=David & Charles|year=1979|isbn=9780715376638|oclc=6916046}}
*{{cite book |title=British Rail Locomotives and other motive power: Combined volume |year=1968 |publisher=[[Ian Allan Publishing|Ian Allan]] |location=London |isbn=0-7110-0008-5 |chapter=British Railways Motive Power Survey |ref={{harvid|Allan|1968}} }}

==Further reading==
*{{cite book|title=Looking back at AC Electric Locomotives|first=Kevin|last=Derrick|publisher=Strathwood|year=2014|isbn=9781905276516|oclc=931820979}}
*{{cite book |last=McManus |first=Michael |title=Ultimate Allocations, British Railways Locomotives 1948 - 1968 |publisher=Wirral. Michael McManus }}

== External links ==
{{commonscat|British Rail Class 84}}
* [http://www.aclocogroup.co.uk/ "The AC Locomotive Group (caring for Class 84 84001)"]
{{British_Rail_Locomotives}}

[[Category:British Rail electric locomotives|84]]
[[Category:Bo-Bo locomotives]]
[[Category:25 kV AC locomotives]]
[[Category:NBL locomotives]]
[[Category:Railway locomotives introduced in 1960]]
[[Category:Standard-gauge locomotives of Great Britain]]
[[Category:Bo′Bo′ electric locomotives]]