View source for British Rail Class 458

{{Short description|Class of British electric multiple-unit trains}}
{{good article}}
{{Use British English|date=June 2020}}
{{Use dmy dates|date=March 2024}}
{{Infobox train
| background = #{{SWR colour}};color:white
| name = British Rail Class 458<br />''Juniper''
| image = 20240625_SWR_458415_WAT.jpg
| imagealt = 
| imagesize = 
| caption = Class 458/4 unit at {{stnlnk|London Waterloo}}
| interiorimage =
| interiorimagealt = 
| interiorcaption = Class 458/4 refurbished interior
| service = 25 February 2000{{snd}}present
| manufacturer = [[Alstom]]
| designer = 
| assembly = 
| ordernumber = 
| factory = {{ubl| [[Barcelona]], [[Spain]]{{efn|bodyshells only<ref name="Factory"/>}}|[[Washwood Heath]], [[Birmingham]]{{efn|Fitting out of trains<ref name="Factory">{{cite magazine|title=Alstom 'Juniper' Platform|magazine=[[Modern Locomotives Illustrated]]|issue=223|date=February 2016|pages=49–59}}</ref>}}}}
| family = [[Alstom Coradia Juniper|''Coradia Juniper'']]
| replaced = {{unbulleted list|{{brc|411}}|{{brc|412}}|{{brc|421}}|{{brc|423}}}}
| yearconstruction = 1998–2002
| yearservice = 
| refurbishment = {{ubl|2008–2010 (interior refresh)|2013–2016 (5-car rebuild)}} 2022–2024 (4-car rebuild, repaint and interior refresh)
| yearscrapped = 
| numberconstruction = 
| numberbuilt = 36<br />(Original fleet of 30, {{avoid wrap|plus 6 converted from [[British Rail Class 460|Cl. 460]])}}
| numberservice = 31<!-- cited in Fleet Details table-->
| numberpreserved =
| numberscrapped = 
| predecessor = 
| successor = 
| formation = {{ubl|4 cars per 458/0 unit as-built:<br />{{abbr|DMCO|Driver's cab, Motor car, Composite (first- and standard-class sections), Open saloon}}-{{abbr|TSO|Trailer car, Standard class, Open saloon}}-{{abbr|MSO|Motor car, Standard class, Open saloon}}-DMCO|5 cars per rebuilt 458/5 unit:<br />{{abbr|DMSO|Driver's cab, Motor car, Standard class, Open saloon}}-TSO-TSO-MSO-DMSO}}
| diagram = 
| code = {{ubl| [[Southern Railway multiple unit numbering and classification#DC EMUs|4-JOP]] (458/0)<ref name="Factory"/>|[[Southern Railway multiple unit numbering and classification#DC EMUs|5-JUP]] (458/5)<ref>{{cite magazine|title='Juniper' Fleet List|magazine=[[Modern Locomotives Illustrated]]|issue=223|date=February 2016|pages=70–71}}</ref>}}
| fleetnumbers = {{unbulleted list|458/0: 458001–458030|458/5: 458501–458536|458/4:458401-458428}}
| capacity ={{ubl|As 4-car 458/4s 234 seats<ref name="Rail1016">{{cite magazine |last=Dunn|first=Pip|title=First of refurbished SWR 458/4s enter traffic|department=Network News| magazine= [[Rail Magazine]] |issue=1016|date=21 August 2024|page=21}}</ref>|As 5-car units: 270 seats}}<ref>{{Cite web|title=Class 458 "Coradia Juniper" |url= https://www.southwesternrailway.com/travelling-with-us/our-trains/class-458-juniper |url-status=live |archive-url= https://web.archive.org/web/20210120064526/https://www.southwesternrailway.com/travelling-with-us/our-trains/class-458-juniper |archive-date=20 January 2021 |access-date=5 January 2022}}</ref>
| owner = [[Porterbrook]]
| operator = {{ubl|Current:|[[South Western Railway]]|Former:|[[South West Trains]]|[[South Western Railway (2017–2025)|South Western Railway (First/MTR)]]}}
| depots = {{ubl|Current|[[Bournemouth Traction and Rolling Stock Maintenance Depot|Bournemouth]]<ref name="RailwaysIllustrated259">{{cite magazine |title= The first refurbished SWR Class 458/4s enter service |magazine= Railways Illustrated|department=News|issue=259 |date=September 2024 |page=12 }}</ref>|Former:|[[Wimbledon TMD|Wimbledon]] ([[London]]){{CN|date=August 2024}}}}
| lines = 
| carbody = [[Steel]]
| trainlength = 
| carlength = {{ubl|DMSO vehs.: {{convert|21.01|m|ftin|abbr=on}}|M/TSO vehs.: {{convert|19.94|m|ftin|abbr=on}}}}
| width = {{convert|2.80|m|ftin|0|abbr=on}}
| height = {{convert|3.77|m|ftin|0|abbr=on}}
| lowfloor = 
| floorheight = 
| platformheight = 
| entrylevelorstep = 
| doors = Double-leaf sliding plug {{avoid wrap|(2 per side per car)}}
| wheeldiameter = 
| wheelbase = 
| maxspeed = {{ubl|458/0 and 458/4: {{convert|100|mph|km/h|0|abbr=on}}|458/5: {{convert|75|mph|km/h|0|abbr=on}}<ref name="fast">{{cite web |url=https://www.lococarriage.org.uk/cl458.html |title=Class 458 |last=Lindop |first=Peter |date=4 April 2000 |website=www.lococarriage.org.uk/ |publisher=The Locomotive & Carriage Institution |access-date=12 June 2020 |quote=458 – A Fast-Track Development?}}</ref>}}
| weight = <!-- {{convert|164.3|t|lk=on}} unclear what variant this refers to -->
| axleload = 
| steep gradient = 
| traction = Alstom ONIX 800 [[Insulated-gate bipolar transistor|IGBT]]
| traction motors = 6 × {{convert|270|kW|abbr=on|sigfig=1}} {{avoid wrap|(2 per motor car)}}
| poweroutput = {{convert|1620|kW|abbr=on|sigfig=1}}
| tractiveeffort = 
| transmission = 
| acceleration = 
| deceleration = 
| aux = 
| powersupply = 
| hvac = 
| electricsystem = {{750 V DC|conductor=y}}
| collectionmethod = [[Contact shoe]]
| uicclass = {{ubl|458/0: 2′Bo′+2′2′+Bo′2′+Bo′2′<ref name="Ju" />|458/5: 2′Bo′+2′2′+2′2′+Bo′2′+Bo′2′}}
| bogies = Alstom ACR<ref name="tr">{{cite book |last1=Marsden |first1=C. J. |title=Traction Recognition |date=2007 |publisher=Ian Allan Publishing |location=Hersham |isbn=978-0-7110-3277-4 |oclc=230804946 |ol=16902750M |url= https://archive.org/details/tractionrecognit0000mars/page/234/mode/2up |pages=234–235 |url-access=registration}}</ref>
| minimum curve = 
| brakes = [[Electro-pneumatic brake system on British railway trains|Electro-pneumatic]] ([[Railway disc brake|disc]]), {{avoid wrap|and [[Regenerative brake#Electric railway vehicle operation|regenerative]]}}
| safety = {{ubl|[[Automatic Warning System|AWS]]|[[Train Protection & Warning System|TPWS]]}}
| coupling = {{ubl|458/0: [[Tightlock coupling|Tightlock]]|458/4 and 458/5: Voith}}
| multipleworking = Within class
| gauge = {{Track gauge|sg|allk=on}}
| notes = 
}}

The '''British Rail Class 458 ''Juniper''''' ([[Southern Railway multiple unit numbering and classification#DC EMUs|4-JOP later 5-JUP]]) is a class of [[electric multiple-unit]] passenger trains of the [[Alstom Coradia Juniper]] family, built at [[Washwood Heath]] between 1998 and 2002 for [[South West Trains]].<ref>{{Cite magazine |url= http://www.railwaygazette.com/news/single-view/view/railtex-2000-review.html |title=Railtex 2000 review |date=1 January 2001 |magazine= Railway Gazette International |access-date=7 June 2018 |url-status=live |archive-url= https://web.archive.org/web/20180607232231/http://www.railwaygazette.com/news/single-view/view/railtex-2000-review.html |archive-date=7 June 2018}}</ref> The order for the original fleet of 30 four-car trains was placed in 1997, and delivery of the first unit followed in October 1998.<ref name=":0">{{Cite web |url= http://www.lococarriage.org.uk/cl458.html |title=458 – A Fast Track Development?|last=Lindop|first=Peter|date=4 April 2000|website=Locomotive & Carriage Institution|archive-url= https://web.archive.org/web/20170305031001/http://www.lococarriage.org.uk/cl458.html |archive-date=5 March 2017 |url-status=live |access-date=7 June 2018}}</ref> The fleet entered passenger service between 2000 and 2003 and is maintained at [[Bournemouth Traction and Rolling Stock Maintenance Depot|Bournemouth depot]].<ref name="RailwaysIllustrated259"/><ref>{{Cite magazine |url= https://modern-railways.keypublishing.com/2015/12/03/golden-spanners-awards-2015/ |title=Golden Spanners Awards 2015 |magazine=Modern Railways |date=3 December 2015 |archive-url= https://web.archive.org/web/20180607232230/https://modern-railways.keypublishing.com/2015/12/03/golden-spanners-awards-2015/ |archive-date=7 June 2018 |url-status=live |access-date=7 June 2018}}</ref>

Between 2013 and 2016, the class was merged with the mechanically similar [[British Rail Class 460|Class 460]] fleet and extensively rebuilt to form a fleet of 36 five-car units—designated Class 458/5—to provide an increase in capacity on services into {{stnlnk|London Waterloo}}.<ref>{{Cite book |title=EMUs A History |last=Llewelyn |first=Hugh |publisher= Amberley Publishing |year=2016 |isbn=9781445649832 }}</ref> The trains are now used by [[South Western Railway (train operating company)|South Western Railway]].<ref>{{Cite magazine |url= https://www.railmagazine.com/news/network/first-train-arrives-late-at-south-western-launch |title=First train arrives late at South Western Railway launch |magazine=Rail Magazine  |location= Peterborough |date=5 September 2017 |archive-url= https://web.archive.org/web/20170909020739/http://www.railmagazine.com/news/network/first-train-arrives-late-at-south-western-launch |archive-date=9 September 2017 |url-status=live |access-date=7 June 2018}}</ref>

In March 2021, South Western Railway announced that 28 Class 458 units would be refurbished for use on long-distance services on the [[Portsmouth Direct line]], as a result of the company deciding to abandon its original plan to use upgraded [[British Rail Class 442|Class 442]] units for this purpose.<ref name="abandon">{{cite magazine |title=SWR abandons '442s' but retains '458s' |url= https://www.modernrailways.com/article/swr-abandons-442sbut-retains-458s |access-date=30 January 2022 |magazine=Modern Railways |publisher=Key Publishing |date=14 April 2021}}</ref> By 2024, this plan had been dropped, and the refurbished units were instead deployed on limited services out of London Waterloo from 24 June 2024.

==History==
South West Trains began operating the [[South Western franchise]] in February 1996, having inherited all of its rolling stock from British Rail. While this included a small number of trains built in the late 1980s and a larger number of suburban units delivered between 1982 and 1985, a significant proportion of the overall fleet was formed by much older [[slam-door trains|slam-door]] First Generation EMUs, such as Classes {{brc|411|n}} and {{brc|423|n}}. In order to begin replacing these older units, SWT issued in November 1996 a request for tenders to supply 30 new air-conditioned four-car EMUs, and in 1997 together with [[Rail transport in Great Britain#Train leasing services|rolling stock lessor]] [[Porterbrook]] awarded to Alstom a £90 million contract for their delivery.<ref name=":0" /><ref name="bbc" />

Some railway industry commentators noted that SWT were going above and beyond the requirements of their franchise award in placing the order, and speculated that it could be a strategy to allay concerns about the fact that the same company—[[Stagecoach Group]]—owned both South West Trains and Porterbrook.<ref name="Ju" /> This represented a potential conflict of interest at a time when rolling stock leasing companies, and Porterbrook in particular, were being criticised for extracting significant profits from leasing cheaply-acquired ex-BR stock.<ref name="laugh">{{cite news |title=Porterbrook Three have a laugh at our expense |url=https://www.independent.co.uk/news/business/porterbrook-three-have-a-laugh-at-our-expense-1307809.html |access-date=3 February 2022 |newspaper=The Independent |date=1 August 1996}}</ref>

[[File:Hugh llewelyn (45)8021 (6336760961).jpg|thumb|left|A Class 458/0 unit in as-delivered condition, showing the original driver's cab and SWT livery]]
All 30 units, numbered 458001–458030, were fitted out at the former [[Metro-Cammell]] works at [[Washwood Heath]] in [[Birmingham]], which Alstom had acquired in 1989, with the bodyshells being built in [[Barcelona]], [[Spain]].<ref name="Factory"/><ref>{{cite magazine|date=18 November – 1 December 1998|title=Alstom's first Juniper unit delivered to South West Trains|magazine=[[Rail Magazine]] |location=Peterborough |issue=344 |issn=0953-4563 |page=7}}</ref> Each unit was formed of two motor cars with driver's cabs, an intermediate trailer car, and an intermediate motor car. Both driving cars had small sections of first-class seating, while the intermediate cars were all standard class. The trailer car was provided with a [[Pantograph (transport)|pantograph]] well and space for an alternating-current transformer, enabling conversion to {{25 kV 50 Hz}} [[Overhead line|overhead-line]] operation if required at a later date.<ref name="Ju">{{Cite web|title=Introduction|url=http://extra.southernelectric.org.uk/features/rolling-stock/458-fall-and-rise/index.html|access-date=23 March 2022|website=extra.southernelectric.org.uk}}</ref> One bogie on each motor car was fitted with traction motors, for a total of 6 motors along the train, a maximum speed of {{convert|100|mph|km/h}}, and a cumulative power output of {{convert|1620|kW|abbr=on|sigfig=1|lk=on}}.<ref name=Ju/> Both driving cars were also provided with end [[Gangway connection|gangways]], with the intent of allowing passengers and crew to move between coupled units. They are the only members of the Juniper family to have such provision.<ref name=Ju/>

The first unit, 458001, was delivered to SWT for pre-acceptance testing on 31 October 1998.<ref name="fast" /> Attempts to place the new class into passenger service were beset by delays and major technical problems. The roofs of the new trains leaked, allowing water ingress to both the driver's cabs and passenger saloons. Onboard electronics repeatedly failed, affecting the air-conditioning and traction systems, and the Train Management System (TMS) software also proved to be unreliable.<ref name=Ju/><ref name=bbc/> More problems were encountered in coupling process and the design of the end gangways{{snd}}existing practice with ex-BR stock taught that units could be coupled or uncoupled in the space of just a few minutes, but the Juniper gangway design was significantly more complex and took far longer to operate. Additionally, the entire TMS had to be restarted whenever units were coupled and uncoupled, which meant that the total time taken to couple or uncouple Class 458 units could reach up to 30 minutes. Both of these facts in particular remained considerable limitations on the use of the new fleet; ultimately SWT had no choice but to treat the Junipers as being semi-permanently coupled in pairs.<ref name=":2">{{Cite web|url=http://extra.southernelectric.org.uk/features/rolling-stock/458-fall-and-rise/index.html|title=Fall and Rise of the 458s|website=extra.southernelectric.org.uk|archive-url=https://web.archive.org/web/20171023222329/http://extra.southernelectric.org.uk/features/rolling-stock/458-fall-and-rise/index.html|archive-date=23 October 2017|url-status=live|access-date=7 June 2018}}</ref> The first Class 458 passenger service eventually ran on 25 February 2000, but even then only two units (458004 and 458005) were available for use.<ref name=Ju/>

[[File:458015 A First Class Interior 1.JPG|thumb|right|The original first-class interior of a Class 458/0 unit]]
By March 2002 twenty-four of the thirty units had been delivered, but on an average day only nine to ten units were actually available for service.<ref name="bbc-old">{{cite news |title=When old trains are better than new |url=https://news.bbc.co.uk/2/hi/uk_news/1878933.stm |access-date=3 February 2022 |work=BBC News |publisher=British Broadcasting Corporation |date=18 March 2002}}</ref> The last six units eventually arrived by October 2002, but it was another seven months—May 2003—before the entire fleet had entered service.<ref name=Ju/> The protracted and difficult introduction of the Juniper fleet is credited with influencing SWT's decision in April 2001 to replace the rest of its slam-door units with an order of 785 vehicles from the competing [[Siemens]] [[Siemens Desiro|Desiro family]].<ref name=":2" /><ref>{{Cite web |url= http://www.semgonline.com/gallery/class450_01.html |title=Class 450|website=semgonline.com|access-date=7 June 2018|url-status=live |archive-url= https://web.archive.org/web/20171123132402/http://www.semgonline.com/gallery/class450_01.html|archive-date=23 November 2017}}</ref>

===Withdrawal from service===
Even after the full complement of units had entered service, reliability remained so poor that in January 2004 South West Trains announced that they would withdraw the entire Class 458 fleet at the December 2005 timetable change in readiness to return them to lessor Porterbrook when the lease on the fleet expired in February 2006.<ref name="bbc">{{cite news |title       = Train firm to replace new fleet |work        = BBC News |date        = 12 January 2004 |url         = https://news.bbc.co.uk/2/hi/uk_news/england/london/3388679.stm |access-date  = 2 July 2008
|quote       = A commuter rail company is to replace 30 of its newest fleet of trains because they keep breaking down. |url-status     = live
 |archive-url  = https://web.archive.org/web/20070313151222/http://news.bbc.co.uk/1/hi/england/london/3388679.stm |archive-date = 13 March 2007}}</ref> At the time of the announcement the trains were only managing an average of {{convert|4300|mi}} between major failures, whereas the new Siemens Desiro ({{brc|450}}) units—which had only entered service in October 2003—were already achieving an average of {{convert|21000|mi}} between faults, and the slam-door fleet had regularly managed intervals of circa {{convert|50000|mi}}.<ref name="bbc" />

An additional 17 Class 450 units had been ordered to replace the Class 458 fleet, but as these new units would not be delivered for some time yet Porterbrook later agreed with SWT that the Junipers could stay in service on a pay-per-use basis past the original end of the lease. In a separate arrangement units 458001 and 458002 were transferred to [[Gatwick Express]] in September 2005 to act as a spare train for that operator, but they were returned to SWT in December 2006 without having been used.<ref>[http://www.southernelectric.org.uk/features/rolling-stock/458-fall-and-rise/gex458.html Gatwick Express 458s] {{webarchive|url=https://web.archive.org/web/20160304195350/http://www.southernelectric.org.uk/features/rolling-stock/458-fall-and-rise/gex458.html |date=4 March 2016 }} – Southern Electric Group. Retrieved 26 December 2010.</ref>

In addition to reliability problems, continued use of the Class 458 fleet was complicated by issues surrounding compliance with the Rail Vehicle Accessibility Regulations (RVAR) 1998<!-- RVAR 1998 IS UNLINKED BECAUSE THE CURRENT RVAR ARTICLE IS SPECIFIC TO 2010 VERSION -->. The Regulations, which mandate the accessibility features that vehicle designers and operators need to provide in order to meet the requirements of the [[Disability Discrimination Act 1995]], were in the process of being formulated at the same time as the Class 458 fleet was being designed and the finished units accordingly received temporary exemptions from compliance on a total of 10 different points.<ref name="1999/2404">{{Cite legislation UK |type=si |year=1999 |number=2404 |si=The Rail Vehicle Accessibility (South West Trains Class 458 Vehicles) Exemption Order 1999 |date=2 September 1999 |access-date=3 February 2022 }}</ref><ref name="2004/2149-exmem">{{cite web |title=Explanatory Memorandum – The Rail Vehicle Accessibility (South West Trains Class 458 Vehicles) Exemption (Amendment) Order 2004 No.2149 |url=https://www.legislation.gov.uk/uksi/2004/2149/pdfs/uksiem_20042149_en.pdf |website=legislation.gov.uk |publisher=The National Archives |access-date=3 February 2022 |date=18 August 2004}}</ref> The exemption relating to the size of the internal passenger information displays expired on 31 July 2006—having already been extended from 30 September 2004—and the Department for Transport declined to provide any further extension.<ref name="1999/2404" /><ref name="2004/2149">{{Cite legislation UK |type=si |year=2004 |number=2149 |si=The Rail Vehicle Accessibility (South West Trains Class 458 Vehicles) Exemption (Amendment) Order 2004 |date=18 August 2004 |access-date=3 February 2022 }}</ref> SWT fitted replacement displays of a compliant size to eight units for use as stand-by stock, while the remainder of the fleet was placed in storage.<ref name=":1">{{Cite journal|date=7 July 2016|title=SWT rolling stock upgrade completed.|journal=Rail Business Intelligence|issue=513|page=6}}</ref>

===Return to service===
In September 2006 the Department for Transport confirmed after a competitive tender process that South West Trains had been awarded a new ten-year contract to operate the [[South Western franchise]], starting in February 2007.<ref name="2007award">{{cite news |title=Stagecoach wins railway franchise |url= https://news.bbc.co.uk/2/hi/business/5369688.stm |access-date=4 February 2022 |work=BBC News |date=22 September 2006}}</ref> As a result of the award, and in keeping with commitments made in its tender, SWT implemented a new rolling-stock plan that called for the withdrawal of its 24 {{brc|442}} units. Class {{brc|444|n}} and 450 units would take over the affected services, and the resulting gaps covered by re-activating the Class 458 fleet.<ref name=":1" /> There was some speculation from industry observers that this was made possible by Porterbrook significantly reducing the amount of money it charged SWT to lease the Junipers, given that there appeared to be no other operators interested in using the fleet.<ref name=":1" />

Following the December 2006 timetable change, the stored Class 458 units began to return to service, and the Class 442 withdrawal was completed on 24 January 2007.<ref name=":1" /> By the end of the following February, observers reported that only four Junipers had not yet been re-activated,<ref name="Ju" /> and that the general reliability of the fleet had improved so much that units now averaged {{convert|17800|mi}} between significant failures (defined as causing delays greater than five minutes).<ref name=":1" />

The re-activation process included the fitting of RVAR-compliant internal displays to the entire fleet. The other points of RVAR non-compliance were covered by existing exemptions that remained valid until 31 December 2010.<ref name="2002/656">{{Cite legislation UK |type=si |year=2002 |number=656 |si=The Rail Vehicle Accessibility (South West Trains Class 458 Vehicles) Exemption Order 2002 |date=8 March 2002 |access-date=4 February 2022 }}</ref>

===Refresh and reliability improvements===
Between 2008 and 2010 the fleet was 'refreshed' at [[Bournemouth Traction and Rolling Stock Maintenance Depot|Bournemouth Traincare Depot]],
during which process the units were fitted with [[Closed-circuit television|CCTV]], new seats and tables in first class, and modified RVAR-compliant lavatories and doorway lights. The interiors were also cleaned and repainted.<ref name="Bournemouth">[http://www.southernelectric.org.uk/features/rolling-stock/458-fall-and-rise/swt458f02.html Class 458s being "refreshed" at Bournemouth T&RSMD] {{webarchive|url=https://web.archive.org/web/20160414105005/http://www.southernelectric.org.uk/features/rolling-stock/458-fall-and-rise/swt458f02.html |date=14 April 2016 }} – Southern Electric Group. Retrieved 21 May 2011.</ref>

In May 2010, SWT enabled [[Regenerative brake|regenerative braking]] on two Class 458 units as part of trial testing its potential use across both the Juniper and Desiro fleets. The trials were successful and regenerative braking was enabled across all 30 Class 458 units by mid-2011.<ref>{{cite press release | url=http://www.southwesttrains.co.uk/Launch-of-regenerative-braking.aspx | title=South West Trains invests £2.2m in regenerative braking system to drive greener trains | publisher=South West Trains | date=4 May 2010 | access-date=6 January 2012 | url-status=usurped | archive-url=https://web.archive.org/web/20130119111335/http://www.southwesttrains.co.uk/Launch-of-regenerative-braking.aspx | archive-date=19 January 2013 }}</ref>

By the end of 2012 the fleet was achieving an average distance of {{convert|106049|mi}} between significant failures; making it the most reliable fleet in Britain and the first to achieve 6-figure mileages.<ref name="MR201301p64">{{cite magazine|title=First six-figure winner tops all-round improvement|author=Ford, Roger|date=January 2013|magazine=Modern Railways|location=London|page=64}}</ref> The feat was recognised with a [[Modern Railways]] magazine ''Golden Spanner'' award in the New Generation EMU category on 23 November 2012.<ref>{{Cite magazine|url=https://modern-railways.keypublishing.com/2012/11/26/class-458-triumphs-at-spanners/|title=Class 458 triumphs at Spanners|date=26 November 2012|magazine=[[Modern Railways]]|archive-url=https://web.archive.org/web/20180612143135/https://modern-railways.keypublishing.com/2012/11/26/class-458-triumphs-at-spanners/|archive-date=12 June 2018|url-status=live|access-date=7 June 2018}}</ref>

==Conversion to Class 458/5==
South West Trains had experienced a considerable shortage of passenger capacity on many of its suburban routes in the years up to 2012, which it attributed primarily to the fact that passenger numbers had increased dramatically without a corresponding rise in the size of the operator's fleet.<ref name=":3" /> The company had suggested to the [[Department for Transport]] on at least three occasions that more {{brc|450}} units should be purchased from Siemens, but had been turned down each time.<ref name="rtm-ashley">{{cite magazine |last1=Ashley |first1=Kate |title=Making the best use of rolling stock |url= https://www.railtechnologymagazine.com/Rail-Industry-Focus-/making-the-best-use-of-rolling-stock |access-date=30 January 2022 |magazine=Rail Technology Magazine |publisher=Cognitive Publishing |date=1 July 2013}}</ref>

As an alternative, Porterbrook proposed to enlarge the Class 458 fleet and reconfigure it for suburban services by using vehicles from the {{brc|460}} fleet, which Porterbrook also owned and which was at that time being released from service with [[Gatwick Express]].<ref name=":3">{{cite news |title=Unwanted, unreliable – but these trains are the answer |url= https://www.railnews.co.uk/news/2013/04/20-unwanted-unreliable--but-these.html |access-date=8 April 2019 |work=Railnews |date=20 April 2013 |archive-url= https://web.archive.org/web/20190330222450/https://www.railnews.co.uk/news/2013/04/20-unwanted-unreliable--but-these.html |archive-date=30 March 2019 |url-status=live }}</ref><ref name="Rail20120125p28">{{cite magazine |title=Class 460 driving vehicles made redundant |last=Clinnick |first=Richard |magazine=Rail |location =Peterborough |date=25 January 2012 |page=28}}</ref> The process, budgeted at £42 million, would allow for all 30 original Class 458 units to be extended by one vehicle, making them into five-car units, after which there would be six five-car Class 460 units left over. These would be comprehensively rebuilt to match the extended Class 458 units, for a total fleet of 36 five-car units that would be designated Class 458/5.<ref name="MR201202p40">{{cite magazine |title=Junipers United: Darth Vader goes suburban |author=Walmsley, Ian |magazine =Modern Railways |date=February 2012 |page=40}}</ref> The units of this "new" fleet would be used—either individually or in pairs of ten cars—to provide extra peak-time capacity on suburban services into Waterloo from the [[Hounslow Loop Line|Hounslow]], [[Chertsey branch line|Weybridge]] (via Staines), and Windsor lines. A separate improvements package agreed between SWT and [[Network Rail]] provided for platform extensions necessary for ten-car operation at over 60 suburban stations, and for the re-opening of one of the four disused platforms at the former [[Waterloo International]] terminal.<ref name="Rail20120111p7">{{cite magazine |title=£42m for longer Waterloo trains |magazine=Rail Magazine |location = Peterborough |date=11 January 2012 |page=7}}</ref><ref name="SWT20111223">{{cite press release |url= http://www.southwesttrains.co.uk/extracapacity.aspx |archive-url= https://web.archive.org/web/20120117060738/http://www.southwesttrains.co.uk/extracapacity.aspx |url-status= usurped |archive-date= 17 January 2012 |title= London commuters to benefit from longer peak time trains |publisher= South West Trains |date= 23 December 2011 |access-date= 30 December 2011 }}</ref><ref name="rtm-first">{{cite magazine |title='A first of a kind engineering project' – SWT's new Class 458-5s |url= https://www.railtechnologymagazine.com/Rail-News/a-first-of-a-kind-engineering-project-swts-new-class-458-5s |access-date=30 January 2022 |magazine=Rail Technology Magazine |publisher=Cognitive Publishing |date=26 February 2014}}</ref>

The Department for Transport announced in December 2011 that it had accepted the proposal,<ref name=":3" /> and an agreement between Porterbrook and South West Trains was signed in January 2012.<ref>{{cite press release |url= http://www.porterbrook.co.uk/pages/corp2012.html#january12 |archive-url= https://web.archive.org/web/20120219223928/http://www.porterbrook.co.uk/pages/corp2012.html#january12 |url-status= dead |archive-date=19 February 2012 |publisher= Porterbrook |title= Porterbrook signs agreement for the future of Class 458s |date= 3 January 2012 }}</ref> South West Trains described the project as advancing its aspiration to become a "10-car railway",<ref name="MR201202p40"/> and the company's fleet director noted that while the project was "much more complicated ... than buying new trains", it was also "significantly cheaper".<ref name=":3" /><ref name="rtm-ashley" /> The primary contract for delivering the project was awarded to Alstom, who appointed [[Wabtec]] to perform the conversion work on its behalf.<ref name=":3" />

[[File:Doncaster railway station MMB 09 460004.jpg|thumb|right|Separated Class 460 vehicles at Doncaster Works prior to being rebuilt]]
All 48 intermediate vehicles from the Class 460 fleet were sent to Wabtec's Doncaster Works to be rebuilt and refitted. Twelve of the 16 driving vehicles were rebuilt by Wabtec subsidiary [[Brush Traction]] at its workshops in [[Loughborough]], where their original driver's cabs were replaced with newly fabricated versions that included gangways and Voith automatic couplers of the same types used on Class 444 and 450 units.<ref name="transforming" /><ref name=":3" /><ref name="prepares" /> Four of the selected driving vehicles had been built with luggage compartments, and these were removed and their roller-shutter external doors were replaced with power-operated plug doors like those used on the other vehicles.<ref name="RG-SWT">{{cite web |url= http://www.southwesttrains.co.uk/longertrains.aspx |archive-url= https://web.archive.org/web/20131109222011/http://www.southwesttrains.co.uk/longertrains.aspx |url-status= usurped |archive-date= 9 November 2013 |title=Improving Your Railway – Longer Trains |publisher= South West Trains |access-date=11 March 2014}}</ref> Together with 18 of the intermediate cars from the Class 460 vehicles, these became the six "new" Class 458/5 units. The remaining 30 Class 460 cars were prepared for insertion into the Class 458/0s.<ref name="transforming">{{cite news |last1=Wordsworth |first1=Nigel |title=Transforming 460s |url= https://www.railengineer.co.uk/transforming-460s/ |access-date=30 January 2022 |work=Rail Engineer |date=15 May 2013}}</ref> 

[[File:South West Trains 458531 + 45853x, Clapham Junction (15464909774) crop.jpg|thumb|right|Two Class 458/5 units soon after being rebuilt. The continuous window band along the vehicle's side only appears on former Class 460 vehicles{{snd}}original Class 458 vehicles have windows separated by bodywork.]]
Additional modifications included re-gearing the traction motors to reduce the train's maximum speed from {{convert|100|mph|km/h|0|abbr=on}} to {{convert|75|mph|km/h|0|abbr=on}}, both to reduce the likelihood of overheating when making frequent stops and starts, and because the higher speed was unnecessary on suburban services.<ref name="rtm-ashley" /> New Train Management System (TMS) software was developed to be compatible across the entire Class 458/5 fleet, simplifying maintenance and improving reliability.<ref name=":3" /> An Automatic Selective Door Opening (ASDO) system was installed for use at a small number of stations where it was impractical to lengthen platforms.<ref name="MR201202p40"/> The vehicle interiors were refurbished and reconfigured to provide more standing room for passengers, mainly by changing from 5- to 4-abreast seating and thus allowing a wider aisle.<ref name="MR201202p40"/><ref name=":3" /> The units were also repainted into SWT's blue livery, matching the Class 450 fleet.

SWT expected to receive the first two Class 458/5 units in May 2013—in time for them to enter service the following November—but due to delays in production the initial delivery did not take place until October.<ref name="RG-SWT" /><ref name="prepares">{{cite magazine |magazine= Railway Gazette International |location= London |title= South West Trains prepares to introduce longer trains |url= http://www.railwaygazette.com/news/single-view/view/south-west-trains-prepares-to-introduce-longer-trains.html |date=23 October 2013 |url-status=live |archive-url= https://web.archive.org/web/20140201171928/http://www.railwaygazette.com/news/single-view/view/south-west-trains-prepares-to-introduce-longer-trains.html |archive-date=1 February 2014 }}</ref> Following testing and staff training, entry into passenger service was achieved in March 2014.<ref name="Rail20120125p28"/><ref name="SWT20111223"/> Once the first four fully-converted units had been delivered and accepted for service, SWT was able to start sending original Class 458/0 units for rebuilding.<ref name="transforming" /> These units received the same modifications as the Class 460 conversions, leaving SWT and Porterbrook with a single mechanically homogenous Class 458/5 fleet. The last unmodified original units were withdrawn from service for rebuilding in November 2015, and returned to SWT after completion on 30 March 2016.<ref name=":1" />

At the conclusion of the conversion project four Class 460 vehicles—all of them driving cars with luggage compartments—were superfluous; these were stripped for spare parts and later scrapped.<ref name="booths">{{cite magazine |title=Redundant Class 460s moved to Booths for scrapping |magazine=Rail |location= Peterborough |date=7 May 2016 |page=27}}</ref>

==Conversion to Class 458/4==
The South Western franchise was transferred from South West Trains to [[South Western Railway (2017–2025)|South Western Railway]] (a [[FirstGroup]]/[[MTR Corporation|MTR]] joint venture) in August 2017. Prior to commencing operations, SWR had taken advantage of low finance costs to order from [[Bombardier Transportation]] a new fleet of 750 vehicles—now designated {{brc|701}}—that would replace Classes {{brc|455|n}}, {{brc|456|n}}, 458, and {{brc|707|n}} on South Western suburban services from late 2019 onwards.<ref name="old-new">{{cite magazine |last1=Clinnick |first1=Richard |title=Old trains... new homes? |url=https://www.railmagazine.com/news/network/old-trainsnew-homes |access-date=1 February 2022 |magazine=Rail Magazine |issue=836 |publisher=Bauer Consumer Media |place=Peterborough |date=19 October 2017}}</ref> However, continuing delays to the Class 701 programme kept all four older fleets in use into the 2020s.<ref>{{cite magazine |last1=Clifton |first1=Paul |title=South Western Railway's £895 million Aventra unveiled - but entry delayed to 2020 |date=19 November 2019 |magazine=Rail Magazine |publisher=Bauer Consumer Media |place=Peterborough |url=https://www.railmagazine.com/news/network/south-western-railway-s-895-million-aventra-unveiled-but-entry-delayed-to-2020 |access-date=16 February 2021}}</ref><ref>{{cite magazine |last1=Clifton |first1=Paul |title=New SWR fleet delayed again |date=23 November 2020 |magazine=Rail Magazine |publisher=Bauer Consumer Media |place=Peterborough |url=https://www.railmagazine.com/news/network/new-swr-fleet-delayed-again |access-date=16 February 2021}}</ref>

South Western Railway had plans to use refurbished {{brc|442}} units for long-distance services to and from London on the [[Portsmouth Direct line]]. However, in March 2021, the operator announced its decision to abandon these plans, citing continuing technical difficulties and future problems complying with accessibility regulations. To make up for the shortfall, 28 Class 458 units have been refurbished and were planned to be redeployed in their place.<ref name="abandon"/> The refurbishment was performed by Alstom at [[Widnes]] in [[Cheshire]] at a cost of £25 million and involved returning each unit to its original four-car formation by removing the Class 460 vehicles, restoring the original maximum speed of {{convert|100|mph|km/h|0|abbr=on}}, and reconfiguration of the passenger saloons.<ref name="grr">{{cite news |title=Alstom to upgrade Porterbrook's Class 458 fleet for South Western Railway |url=https://www.globalrailwayreview.com/news/120716/alstom-upgrade-porterbrook-class-458-fleet/ |access-date=30 January 2022 |work=Global Railway Review |publisher=Russell Publishing |place=Brasted |date=7 April 2021}}</ref> The reconfigured units will be leased from Porterbrook until 2027 at the earliest and are maintained at [[Bournemouth Traction and Rolling Stock Maintenance Depot]].<ref name="RailwaysIllustrated259"/><ref name="rt-selects">{{cite news |title=Porterbrook selects Alstom to upgrade Class 458 train fleet |url=https://www.railway-technology.com/news/porterbrook-selects-alstom-to-upgrade-class-458-train-fleet/ |access-date=22 April 2021 |work=Railway Technology |publisher=GlobalData |date=7 April 2021}}</ref><ref name="advent">{{cite news |last1=Duggan |first1=Jamie |title=Refurbishment for SWR's Class 458 trains thanks to new contract between Porterbrook and Alstom |url=https://www.railadvent.co.uk/2021/04/refurbishment-for-swrs-class-458-trains-thanks-to-new-contract-between-porterbrook-and-alstom.html |access-date=1 February 2022 |work=Rail Advent |date=15 April 2021}}</ref> The first two units to be sent for refurbishment, 458507 and 458517, arrived at Widnes by mid-August 2022.<ref>{{cite magazine |last1=Pickering |first1=Graeme |title=SWR Class 458s are Widnes-bound |magazine=The Railway Magazine |date=September 2022 |issue=1458 |page=92 |publisher=Mortons Media Group |location=Horncastle |issn=0033-8923}}</ref>

Testing for the 458/4s began on 9 October 2023.<ref>{{cite magazine|title= Main line testing starts for 4 car 458s |magazine=[[Today's Railways UK]]|issue=262|date=December 2023|page=60}}</ref>

In early 2024 it was announced that the plan to use the Class 458/4s on Portsmouth services had been dropped.<ref name="MR905">{{cite magazine|title=No immediate plan to introduce refurbished '458s' |department=News Front|magazine= [[Modern Railways]] |issue=905|volume=81|date=February 2024|page=9}}</ref><ref>{{cite magazine|last=Clifton|first=Paul|title=Why are the Class 701 Arterios more than four years late? |magazine= [[Rail Magazine]] |issue=1002|date=7 February 2024|pages=30–31}}</ref> Later in May 2024, it was announced that the Class 458/4s would instead be used on some limited outer suburban services from London Waterloo.<ref name="RE337">{{cite magazine|last=Russell|first=David|title=June launch for modified Class 458/4s|department= Units|magazine=[[Rail Express]] |issue=337|date=June 2024|page=22}}</ref> The first Class 458/4 entered service on 24 June 2024,<ref name="458/4entrytoservice">{{Cite web |date=24 June 2024 |title=Earlier today we introduced the first of our freshly refurbished Class 458/4 trains, which will initially be used to operate services between London Waterloo and Weybridge, via Hounslow and Twickenham, as our Head of Fleet Delivery, James Wale explains
|url=https://x.com/sw_help/status/1805228676239270276 |access-date=24 June 2024 |website=X |publisher=@SW_Help}}</ref> with the entire converted fleet in service by May 2025.<ref name="RE341">{{cite magazine|last=Russell|first=David|title=Class 458 Juniper|department=Units|magazine=[[Rail Express]]|issue=341|date=October 2024|page=23}}</ref><ref name="RE350">{{cite magazine|last=Russell|first=David|title=Class 458 Juniper|department=Units|magazine=[[Rail Express]]|issue=350|date=July 2025|page=23}}</ref>

The 458/4 conversion and refurbishment was completed on 12 December 2024.<ref name="complete">{{cite magazine |url=https://www.modernrailways.com/article/alstom-completes-ps25-million-class-458-refurbishment-project |title=Alstom completes £25 million Class 458 refurbishment project |magazine=Modern Railways |date=17 December 2024 |access-date=17 December 2024}}</ref> Scrapping of the redundant ex-Class 460 vehicles started in January 2025.<ref>{{cite magazine|last=Russell|first=David|title=Class 458 Juniper|department=Units|magazine=[[Rail Express]]|issue=346|date=March 2025|pages=22–25}}</ref>

==Incidents==
* On 30 January 2015, a small explosion occurred underneath a driving vehicle of unit 458501 near [[Windsor & Eton Riverside railway station|Windsor & Eton Riverside station]]. The [[Rail Accident Investigation Branch]] determined that this was caused by a join between three underfloor power cables not being secured correctly when the unit was rebuilt in 2014.<ref>{{cite book |title=Report 18/2015: Electrical arcing and fire under a train near Windsor & Eton Riverside, 30 January 2015 |date=21 October 2015 |publisher=Rail Accident Investigation Branch, Department for Transport |location=Derby |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/469982/R182015_151021_Windsor.pdf |access-date=25 January 2016 |url-status= live |archive-url=https://web.archive.org/web/20160222185301/https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/469982/R182015_151021_Windsor.pdf |archive-date=22 February 2016 }}</ref>
* On 21 December 2019, unit 458519 was involved in a collision with a car between Wokingham and Bracknell. Nobody was seriously injured.<ref>{{Cite news|last1=Aldridge|first1=James|last2=Ovens|first2=Ruth|date=20 December 2019|title=Recap after crash at level crossing in Wokingham|url=https://www.getreading.co.uk/news/reading-berkshire-news/live-updates-trains-blocked-wokingham-17450606|access-date=22 April 2021|work=BerkshireLive}}</ref><ref>{{Cite news|title=Man arrested on suspicion of drink driving after BMW and train collide at level crossing|url=https://www.bracknellnews.co.uk/news/18114417.car-hits-train-level-crossing-wokingham-ascot/|access-date=22 April 2021|work=Bracknell News}}</ref>

==Fleet details==
{| class="wikitable"
!Class
!Operator
!Qty.
!Year built
!Year converted
!Cars per unit
!Unit nos.
!Notes
|-
!458/4
| rowspan="3" |[[South Western Railway]]
| align="center" |28
| rowspan="5" align="center" |1998–2002
| align="center" |2022–2024
| align="center" |4
| align="center" |458401–458428<ref name="TRUK276">{{cite magazine|last1=Pritchard|first1=Robert|last2=Beardsley|first2=Ian|title=Alstom marks completion of 458/4 refurbishment|department=Rolling Stock News|magazine=[[Today's Railways UK]]|issue=276|date=February 2025|page=59}}</ref>
|Converted from Class 458/5s by removing the Class 460 intermediate vehicle.<ref>{{cite magazine |title= '707s' to move to Southeastern |magazine=[[Modern Railways]] |issue=900  |date=September 2023 |page=83}}</ref><ref>{{Cite web |title=Refurbished 458 arrives at Bournemouth – Southern Electric Group |url=https://www.southernelectric.org.uk/2023/07/19/refurbished-458-arrives-at-bournemouth/ |access-date=26 August 2023}}</ref>
|-
! rowspan="4" align="center" |458/5
|align="center" |1
| rowspan="4" align="center" |2013–2016
| rowspan="4" align="center" |5
|align="center" |458529<ref name="RE352">{{cite magazine |last=Russell |first=David |date=September 2025 |title=Class 458|department=Units|magazine=[[Rail Express]] |issue=352 |page=24}}</ref>
|Original fleet of four-car Class 458/0 units, extended to five cars by inserting a rebuilt Class 460 intermediate vehicle.
|-
|align=center|2
|align="center" |458533, 458535<ref name="RE352"/>
|align="center" |Converted from {{brc|460}} units.<ref name=":3" />
|-
| rowspan="2" align="center" |Stored
|align="center" |1
|458530<ref name="RE352"/>
|Original fleet of four-car Class 458/0 units, extended to five cars by inserting a rebuilt Class 460 intermediate vehicle.
|-
|align="center" |4
|458531–458532, 458534, 458536<ref name="RE352"/><ref>{{cite magazine|last=Russell|first=David|title=Class 458 Juniper|department=Units|magazine=[[Rail Express]]|issue=349|date=June 2025|page=23}}</ref>
|align="center" |Converted from {{brc|460}} units.<ref name=":3" />
|}

==Notes==
{{notelist}}

==References==
{{Reflist}}

==Further reading==
{{Commons category|British Rail Class 458}}
* {{cite magazine|title=Alstom's Juniper production line to complete an SWT unit every fortnight|first=Mel|last=Holley|magazine=[[Rail Magazine]]|issue=345|publisher=EMAP Apex Publications|date=2–15 December 1998|pages=18–19|issn=0953-4563|oclc=49953699}}

{{Coradia/Juniper|state=collapsed}}
{{British Rail EMU|state=collapsed}}

[[Category:British Rail electric multiple units|458]]
[[Category:Alstom Coradia Juniper]]
[[Category:Train-related introductions in 2000]]
[[Category:750 V DC multiple units]]