Class 25 Bo-Bo Diesel Locomotives

Class 25 are Sulzer powered, built at Derby

and have a maximum speed of 90 mph.

[Author & photographer © Dr Phil Brown PhD

(plus text help from AI these days), page updated May 6th 2026]

D7628 SYBILLA is one of twenty Class 25 diesel locomotive to survive of its class and operates on the NYMR. Class 25 diesel locomotive 25059 and D5185 are also featured.

A history of Class 25 diesel electric locomotives

My Archive Steam Photos from the 1960s

Class 25 diesel locomotive 25059 (25 059 in British Rail blue livery) at Keighley station double heading a special with 66784 as part of the  Keighley & Worth Valley Railway, 50th Anniversary gala week in June 2018

TOP of PAGE

Class 25 D5185 with a passenger train at Loughborough (GCR Diesel Gala, Sept. 2017)

Class 25 D5185 at Leicester North with a train from Loughborough (GCR Diesel Gala, Sept. 2017)

Class 25 D5185 with a passenger train at Loughborough Central (GCR Diesel Gala, Sept. 2017)

TOP of PAGE

Class 25 diesel D7628 SYBILLA with an NYMR service, turning round on the loop at Whitby station to return to Grosmont.

NYMR Diesel Gala 2011: Class 25 Bo-Bo Type D7628 SYBILLA built in 1965 (Class 25 25278)

Class 25 diesel D7628 Sybilla waits at Grosmont with an NYMR railway service for Pickering (44806 on the left)

Steam and diesel heritage railway trains side by side!

TOP of PAGE

Class 25 D7628 leaves Goathland with a train for Pickering.

Diesels on the Great Central Railway: Ex British Railways Class 25 D5185 (D 5185) CASTELL DINAS BRAN in BR green livery. This a BR Sulzer Class 25 diesel-electric locomotive built at Darlington North Road Locomotive Works in 1963, later named as Bo-Bo Type 25 25035 (25 035).

NYMR Diesel Gala 2011: Class 25 D7628/D 7628 stands next to Class 24 D5061/D 5061 at Grosmont station.

TOP of PAGE

Class 25 D7628 ascending the bank near Green End

Class 25 D7628 is called "SYBILLA", here hauling a Pickering-Grosmont train into Goathland station (other numbers (D 7628, 25278, 25 278).

TOP of PAGE

A history of Class 25 diesel electric locomotives

The British Rail Class 25—also known as the Sulzer Type 2—were 327 mixed‑traffic diesel‑electric locomotives built between 1961 and 1967, evolving from the earlier Class 24 and becoming one of BR’s most widely used Type 2 designs.

Origins and Development of the Class 25 diesel-electric locomotives

The Class 25 emerged from the 1955 Modernisation Plan, which sought a new generation of diesel locomotives to replace steam. The earlier Class 24 proved under‑powered and limited to 75 mph; Sulzer’s improved 6LDA28‑B engine, fitted with an intercooler, raised output to 1,250 hp, enabling a higher 90 mph top speed. This upgrade formed the basis of the Class 25.

Production took place at:

• BR Darlington Works

• BR Derby Works

• BR Crewe Works

• Beyer, Peacock & Co., Manchester (36 locomotives)

A total of 327 locomotives were built between 1961–1967, numbered D5151–D5299 and D7500–D7677 (later 25001–25327).

Technical Characteristics of the Class 25 diesel-electric locomotives

Key features included:

• Bo‑Bo wheel arrangement

• Sulzer 6LDA28‑B six‑cylinder diesel engine

• 1,250 hp output

• Top speed 90 mph

• Starting tractive effort 39,000–45,000 lbf

• Steam heating boilers fitted to many for passenger work

• Blue Star multiple‑working capability

Their compact size and versatility earned them the enthusiast nickname “Rats”, reflecting their ubiquity across the network.

Sub‑Classes and Design Evolution of the Class 25 diesel-electric locomotives

The Class 25 family developed through several sub‑classes, each with mechanical and cosmetic changes:

Class 25/0 (D5151–D5175)

• Built at Darlington

• BTH electrical equipment

• Cab‑front connecting doors and roof‑mounted headcode box

Class 25/1 (D5176–D5232)

• Built at Darlington and Derby

• Switch to AEI traction motors

• Revised fuel/water tanks; cab skirts removed

Class 25/2 (D5233–D5299, D7500–D7597)

• Major bodywork redesign: removal of cab‑front doors, enlarged centre window

• Bodyside grilles moved to cantrail level

• New two‑tone green livery

Class 25/3 (D7598–D7677)

• Built at Derby and Beyer Peacock

• Introduction of solid‑state electronics

• Final 18 units completed at Derby due to Beyer Peacock’s financial issues

Class 25/9 (1985)

• Twelve Class 25/3s modified for ICI road‑salt trains from Winsford

• Withdrawn when the contract was lost

ETHEL Units (1983)

Three Class 25/3s converted into Electric Train Heating Ex‑Locomotives, used as mobile generators for passenger stock in Scotland.

Operational Service of the Class 25 diesel-electric locomotives

Class 25s were true mixed‑traffic locomotives, handling:

• Freight (coal, minerals, general merchandise)

• Passenger services (especially on secondary routes)

• Engineering trains

• Multiple‑unit formations of up to three locomotives

They were widely used across the BR network, though the Eastern and Southern Regions never had long‑term allocations.

Withdrawal and Preservation of the Class 25 diesel-electric locomotives

Withdrawals began in 1971 (accident damage) and accelerated through the 1980s, with the final locomotive retired in March 1987.

Of the 327 built, around 20 survive in preservation, many operational on heritage railways.

TOP of PAGE

TOP of PAGE

My Archive Steam Photos from the 1960s

docspics images of Class 25 diesel locomotive rail tour holidays photos of Class 25 diesel locomotive rail tour holidays photographs of Class 25 diesel locomotive rail tour holidays pictures of Class 25 diesel locomotive rail tour holidays © Dr Phil Brown * Treyn Railway Holidays to France, Italy and Spain from Class 25 diesel locomotive rail tour holidays Booking tickets for Great Railway Journey luxury Rail Trip holidays Train travel in Europe Rail holidays from Class 25 diesel locomotive rail tour holidays to the USA & Canada luxury train through the Rocky Mountain Canadian rail railway holidays through the Rockies US Cities by train from Class 25 diesel locomotive rail tour holidays  Continental rail holidays to France Germany Italy Austria Switzerland Glacier Express Treyn Holidays from Class 25 diesel locomotive rail tour holidays from Eurostar to Paris Brussels Avignon Turin Turino Rome Roma Florence Firenze TGV fast trains Railway travel holidays special steam excursions from Class 25 diesel locomotive rail tour holidays great steam heritage line and offers luxury Pullman coach dining trains Class 25 diesel locomotive rail tour holidays Travelling by train always seems a pleasure, especially if through wonderful scenery  to Class 25 diesel locomotive rail tour holidays in England, Scotland, Wales or on holiday in the rest of Europe! The railway trip from Class 25 diesel locomotive rail tour holidays involves seeing or travelling behind a 'real' steam locomotive in action and there is nothing like the sight and sounds of a steam train to invoke feelings of nostalgia in some of us to Class 25 diesel locomotive rail tour holidays even more luxury by having a special trip out on a steam dining train! England Scotland Wales Northern Ireland top class hotels in Class 25 diesel locomotive rail tour holidays dining out travel tours top tourist destinations tourist information on Class 25 diesel locomotive rail tour holidays weekend breaks mini-breaks family holidays restaurants touring coach trips from Class 25 diesel locomotive rail tour holidays continental tours cruise ships pleasure cruises summer breaks spring breaks continental winter breaks European winter holidays spring holidays summer holidays European Rail tours Railway travel holidays special steam excursions from Class 25 diesel locomotive rail tour holidays A great steam heritage line and offers luxury Pullman coach dining trains European Rail tours US and Canadian Railway travel holidays special steam excursions to Class 25 diesel locomotive rail tour holidays A great steam heritage line and offers luxury Pullman coach dining trains Travelling by train from Class 25 diesel locomotive rail tour holidays always seems a pleasure, especially if through wonderful scenery either in England, Scotland, Wales or on holiday in the rest of the railways of Europe! The railway trip involves seeing or travelling behind a 'real' steam locomotive or heritage diesel in action on a special trip from Class 25 diesel locomotive rail tour holidays Booking Eurostar Continental Rail Travel Tour Tickets Stuttgart Brussels Eurostar Brussels from Class 25 diesel locomotive rail tour holidays by TGV to Ebbsfleet International, Ashford International Stratford International, St Pancras International Paris Gare du Nord Paris Gare de Lyon Paris Gare de L'est Paris Gare Montparnasse by Eurostar from Class 25 diesel locomotive rail tour holidays London to Paris, Eurostar London - Brussels Eurostar London to Lille deals bargain city breaks Class 25 diesel locomotive rail tour holidays Great Railway Journey holidays in Italy, Spain and France by TGV booking from Class 25 diesel locomotive rail tour holidays Booking Eurostar Continental Rail Travel Tour Tickets to the Continent  eg Paris Brussels Avignon or railway tours across France, Holland, Austria, Czech Republic, Hungary, Russia, Asia or China for a travel spectacular Class 25 diesel locomotive rail tour holidays

Good trainspotting 'TRAINSPOTS' Good trainspotting and photographic locations  Barnetby Station, North Lincolnshire  *  Carlisle Station  *  Clapham Junction Station, London  *  Colton Junction, south of York  *  Crewe Station  *  Doncaster Station, South Yorkshire  * Hellifield station - Carlisle to Settle line * Lancaster station  * Newcastle Station  *  Northallerton Station  *  Nuneaton Station  *  Sheffield Station  *  Stratford Station, East London * Warrington Bank Quay station * Wigan North Western - WCML *  York Station

See other TOPS classes * Class 01 * Class 02 * Class 03 * Class 04 * Class 08 * Class 09 * Class 10 * Class 11 * Class 14 * Class 20 * Class 24 * Class 25 * Class 26 * Class 27 * Class 31 * Class 33 * Class 35 * Class 37 * Class 40 * Class 43 * Class 44 * Class 45 * Class 47 * Class 50 * Class 52 * Class 55 * Class 56 * Class 57 * Class 58 *  Class 60 * Class 66 * Class 67 * Class 68 * Class 70 * Class 71 * Class 73 * Class 76 * Class 77 *  Class 84 * Class 86 * Class 87 * Class 88 * Class 90 * Class 91 * Class 92 * Derby Lightweight * Class 101 * Class 108 * Class 114 * Class 117 * Class 120 * Class 121 * Class 122 * Class 127 * Class 141 * Class 142 * Class 144 * Class 150 * Class 153 * Class 155 * Class 156 * Class 158 * Class 159 * Class 165 * Class 166 * Class 170 * Class 172 * Class 175 * Class 180 * Class 185 * Class 195  * Class 196 * Class 197 * Class 220 * Class 221 * Class 222 * Class 252 * Class 313 * Class 315 * Class 317 * Class 319 * Class 320 * Class 321 * Class 322 * Class 323 * Class 325 * Class 331 * Class 332 * Class 333 * Class 334 * Class 350 * Class 357 * Class 360 * Class 365 * Class 373 * Class 375 * Class 376 * Class 377 * Class 378 * Class 379 * Class 380 * Class 387 * Class 390 * Class 395 * Class 414 * Class 423 * Class 442 * Class 444 * Class 450 * Class 455 * Class 458 * Class 460 * Class 465 * Class 466 * Class 489 * Class 507/508 * Class 700 * Class 730  * Class 755 * Class 800 * Class 801 * Class 802 * Class 803 *  Class 805 * Class 3000 *

IMAGES OF PRESERVED STEAM LOCOMOTIVES

TOP of PAGE