View source for British Rail Class 12

{{Short description|Diesel locomotive class (1949–1971)}}
{{Use dmy dates|date=February 2015}}
{{Use British English|date=February 2015}}
{{Infobox locomotive
|name            = British Rail Class 12
|powertype       = Diesel-electric
|image           = BR class 12 shunter 15224.jpg
|caption         = 15224 at Tunbridge Wells West, Spa Valley Railway
|builder         = [[British Railways]] [[Ashford Works]]
|ordernumber     = SR 3413 (15), 3537 (11)
|builddate       = 1949–1952
|totalproduction = 26
|whytetype       = {{whyte|0-6-0|DE}}
|uicclass        = C
|gauge           = {{Track gauge|ussg|allk=on}}
|wheeldiameter   = {{convert|4|ft|6|in|m|3|abbr=on}}
|wheelbase       = {{convert|11|ft|6|in|m|2|abbr=on}}
|minimumcurve    =
|length          = {{convert|29|ft|5+1/2|in|m|2|abbr=on}}   
|width           = {{convert|9|ft|0|in|m|2|abbr=on}}    
|height          = {{convert|12|ft|8+1/2|in|m|2|abbr=on}}  
|locoweight      = {{convert|48|LT|t ST|sigfig=3|lk=on}}
|fuelcap         = {{convert|660|impgal|abbr=on}}
|primemover      = [[English Electric diesel engines|English Electric 6KT]]
|generator        = English Electric 801/7D ([[Direct current|DC]])
|tractionmotors  = [[English Electric]] 506A, 2 off
|transmission    = [[Diesel-electric transmission|Diesel electric]], [[double reduction gearing]]
|multipleworking = Not fitted
|maxspeed        = {{convert|27.5|mph|km/h|1|abbr=on}}
|poweroutput     = ''Engine:'' {{convert|350|hp|0|abbr=on|lk=on}}
|tractiveeffort  = ''Maximum:'' {{convert|24600|lbf|kN|1|abbr=on|lk=on}}
|trainheating    = None
|locobrakeforce  =
|trainbrakes     = None; 15230–15232 [[Railway airbrake|Air]] from 1970
|operator        = [[British Railways]]
|operatorclass   = D3/13, later 3/9, later Class 12
|fleetnumbers    = 15211–15236
|axleloadclass   = [[Route availability|RA]] 5
|preservedunits  = 15224 at the [[Spa Valley Railway]]
|withdrawndate   = 1968-1971
|disposition     = One preserved, remainder [[scrap]]ped
|notes           = References: {{sfn|Marsden|1981|loc="SR: 15211-15236"}}
}}
The [[British Rail]] '''Class 12''' is a [[diesel locomotive]] built primarily for [[Switcher|shunting]] duties around London.

==History==
This was the second batch of [[Southern Railway (UK)|Southern Railway]] shunters based on the [[English Electric]] 6KT 350&nbsp;hp (260&nbsp;kW) diesel engine.  The first experimental batch (BR numbers 15201–15203) were designed by [[Richard Maunsell]] of the SR in 1937 and were later classified [[British Rail Class D3/12|D3/12]]. These locomotives were [[Oliver Bulleid]]'s development of Maunsell's original design, but were significantly lighter. They featured Bulleid's distinctive [[Bulleid Firth Brown wheel|BFB wheels]], and incorporated a number of details from the [[LMS diesel shunters 7059-7068|diesel-electric shunters]] produced by the [[London, Midland and Scottish Railway]] 1936–39.{{sfn|Bradley|1975|p=52}} They were built at the [[Ashford railway works|BR Ashford Works]] over the period 1949–1952 and numbered 15211–15236. They later became Class 12, but no locomotives survived long enough to acquire Class 12 [[TOPS]] numbers.

==Technical details==
The [[diesel engine]] is an [[English Electric]] 6-cylinder, 4-stroke, 6KT and the [[traction motor]]s are two EE506 axle-hung, nose-suspended, force-ventilated traction motors with 17.5:1 double reduction gear drive. The [[Electrical generator|main generator]] is an EE type EE801/7D, flange-mounted single bearing rated at 490&nbsp;kW.

==Operational details==
The locomotives were designed for use in the two South London [[marshalling yard]]s at [[Norwood Junction railway station#Marshalling yard|Norwood Junction]] and [[Hither Green railway station|Hither Green]], and remained there for much of their working lives. 

Four (15230–15233) were fitted with air train braking originally for the 1966 [[South West Main Line|Bournemouth line]] electrification scheme and the need for air brake depot shunters and station pilots; based at [[Bournemouth]] 1967 but re-allocated 1968 to [[Ashford, Kent|Ashford]] and then often used at [[Dover]] shunting continental ferry vans before [[British Rail Class 08|Classes 08]] and [[British Rail Class 09|09]] were generally converted to this system. They were also utilised as works shunters at [[Ashford railway works|Ashford]], [[Brighton railway works|Brighton]] and [[Eastleigh railway works|Eastleigh]].

==Withdrawal and preservation==
The entire class was withdrawn between 1968 and 1971 and most were scrapped soon afterwards. However, three were sold for industrial use with two of those locomotives being scrapped later on.{{sfn|Strickland|1983|p=63}} One, 15222, had been used as a generator by a quarry in [[South Wales]] having been acquired from the [[Newport, Wales|Newport]] scrapyard of [[John Cashmore Ltd]]. A second, 15231, was sold by BR to Tilling Construction at [[Grassington]]. The third, 15224, was sold by BR to the [[National Coal Board]] for use in the [[Kent Coalfield]]. It was used at [[Betteshanger]] and [[Snowdown]] collieries, and was preserved in 1982. It is now the only surviving locomotive of the class, and is awaiting overhaul at the [[Spa Valley Railway]], [[Royal Tunbridge Wells]]. A detailed overhaul and restoration scoping plan is in development; the locomotive requires a complete re-wire as the original wiring is suffering age related deterioration. As of January 2021, the project is on hold awaiting suitable funding.

{| class="wikitable" style="text-align:center"
|+ Table of withdrawals{{sfn|Strickland|1983|p=63}}
! Year !! Quantity in<br>service at<br>start of year !! Quantity<br>withdrawn !! Locomotive numbers
|-
| 1968 || 26 ||  4 || align=left | 15213/15/34/36.
|-
| 1969 || 22 ||  5 || align=left | 15216/23/26/28/33.
|-
| 1970 || 17 ||  3 || align=left | 15217–18/27.
|-
| 1971 || 14 || 14 || align=left | 15211–12/14/19–22/24–25/29–32/35.
|-
|}

==Footnotes==
{{Reflist}}

==References==
* {{cite book |last=Bradley |first=D.L. |year=1975 |title=Locomotives of the Southern Railway, Part 1. |publisher=[[Railway Correspondence and Travel Society]] |location=Oxford  |isbn=0-901115-30-4 }}
* {{cite book |last=Marsden |first=Colin |year=1981 |title=The diesel shunter: a pictorial record |publisher=Oxford Publishing Company |location=Oxford |isbn=0-86093-108-0 }}
* {{Strickland Locomotive Directory}}

==Further reading==
* {{cite book |last=McManus |first=Michael |title=Ultimate Allocations, British Railways Locomotives 1948 - 1968 |location=Wirral |publisher=Michael McManus }}

{{SR Locomotives}}
{{British Rail Locomotives}}

[[Category:British Rail diesel locomotives|12]]
[[Category:English Electric locomotives]]
[[Category:C locomotives]]
[[Category:Railway locomotives introduced in 1949]]
[[Category:Standard-gauge locomotives of Great Britain]]
[[Category:Diesel–electric locomotives of Great Britain]]
[[Category:Shunting locomotives]]