British Rail Class 46 – Derby's Brush-Equipped Peaks 1961-1984

Historical Background and Context

The Class 46 emerged from British Railways' ambitious 1955 Modernisation Plan, which allocated £1.24 billion to eliminate steam traction by 1968. Built exclusively at Derby Works from 1961-1963, these locomotives represented the third evolution of the successful Peak diesel-electric family. The lineage began with Class 44 (D1-D10, 1959-1960) using the non-intercooled Sulzer 12LDA28-A engine producing 2,300 bhp with Crompton Parkinson electrical equipment. The improved Class 45 (D11-D137, 1960-1962) introduced the intercooled Sulzer 12LDA28-B engine boosting output to 2,500 bhp while retaining Crompton Parkinson equipment.

The Class 46 diverged by adopting Brush electrical equipment—generators and traction motors—while using the same 2,500 bhp Sulzer engine as the Class 45. This strategic decision by the British Transport Commission tested Brush as an alternative supplier, a gamble that paid off spectacularly. After ordering 56 Class 46 locomotives, the BTC cancelled the final 20 units on order and invited competitive bids for a new Type 4 specification using the Brush equipment intended for those cancelled locomotives. Brush Traction won this contract, resulting in the highly successful Class 47 with 512 units built—validating the electrical system choice that made the Class 46 so significant.

The Type 4 designation indicated locomotives in the 2,000-2,999 horsepower range, representing BR's most powerful diesel-electric main line locomotives below the 3,300 bhp Type 5 Deltics. These were intended for express passenger services on non-electrified main lines and heavy freight requiring sustained high power output at the 90 mph maximum speed rating.

Derby Works possessed specialised expertise in Sulzer engine installation and had built all preceding Peak classes, making it the natural choice for Class 46 construction. The facility employed traditional locomotive assembly with fabricated body construction, cast bogies, and integrated diesel-electric components in what would become the final generation of this design before the more successful integral-body Class 47 took over.

All 56 Class 46 locomotives were built continuously from 1961 through 1963, numbered D138-D193 in the pre-TOPS era. These were later renumbered 46001-46056 under the TOPS classification system introduced in the early 1970s, following a simple sequential conversion: D138 became 46001, D139 became 46002, continuing through D193 as 46056. The build divided into two identifiable batches based on headcode panel configuration, with D138-D173 receiving two-aspect headcode panels and D174-D193 featuring four-aspect headcode panels from new.

Design and Technical Specifications

The engineering excellence of the British Rail Class 46 lay in the sophisticated Sulzer-Brush combination that distinguished it from Peak siblings. At the heart of the design sat the Sulzer 12LDA28-B twin-bank diesel—a 12-cylinder two-stroke compression ignition engine producing 2,500 bhp at 750 rpm. The double-bank configuration (two parallel 6-cylinder banks geared to a single output shaft) provided compact packaging compared to conventional V-configuration or inline engines of equivalent power. The intercooling delivered 200 bhp more than the Class 44's non-intercooled variant while maintaining reliability—a significant thermal efficiency improvement.

The Brush electrical system distinguished the Class 46 from its Crompton Parkinson-equipped Class 45 sisters. The Brush TM73-68 main generator drove six Brush TM64-68 traction motors in a diesel-electric transmission with one traction motor per powered axle. This arrangement provided independent control of each motor through Brush electrical components, delivering smooth power application and superior adhesion characteristics compared to earlier diesel designs.

The unusual 1Co-Co1 wheel arrangement solved a critical problem: the BR Civil Engineer imposed a strict 20 long tons maximum axle loading. The original Co-Co design (six powered axles without pony trucks) couldn't meet this weight limit given the locomotive's 135-tonne mass. The solution borrowed the pony truck bogie design from Southern Railway locomotives 10201-10203, distributing weight across eight axles instead of six. This reduced individual axle loading while maintaining the six independently-powered axles needed for maximum adhesion and tractive effort.

The design inherited problems from the broader Peak family. Bogie frame cracking plagued all three classes throughout their service lives, caused by stresses from negotiating sharp curves with long bogies and the unusual decision to mount buffing gear on the bogies rather than the main frame. The vacuum exhausters suffered from problematic central engine room placement, requiring crane removal through the roof—an 8-12 hour maintenance task. Steam heating boiler water tank fractures caused significant problems, and first-generation teething troubles affected batteries, auxiliary motors, and various systems throughout the 1960s.

Service History and Operations

The Class 46 fleet entered service between 1961-1963 with initial allocations to multiple depots for crew training and route learning. Derby MPD, Toton, Nottingham, Gateshead, and Holbeck received the initial batches. One documented example, D182 (46045), entered service in September 1962 at Gateshead and remarkably remained allocated there throughout its entire career—a rarity in BR practice demonstrating the depot's long association with Peak-class locomotives.

Express passenger services formed their primary duty, with regular workings on prestigious named trains including the Yorkshire Pullman, Flying Scotsman, Hull Executive, Thames-Clyde Express (North East-South West), and The Waverley (Carlisle-Edinburgh route). They handled Trans-Pennine services between Liverpool/Manchester and York/Leeds, secondary North East-London trains on the Midland Main Line, and North East-South West cross-country routes from Newcastle through Bristol to Plymouth and Penzance.

The most distinctive Class 46 working became the "clay hoods"—specialised china clay trains from Cornwall to the Staffordshire Potteries at Stoke-on-Trent. These long-distance block freight trains hauled 15-30+ OOV/UCV wagons (wooden construction with tarpaulin "hood" covers in various blue shades) and later PRA "Clay Tigers" air-braked bogie wagons. This working became so associated with the class that it represents an essential modelling scenario for enthusiasts seeking authentic operations.

During the mid-1960s, locomotives D138-D166 underwent refurbishment at Brush, Loughborough, receiving single-piece central headcode panels replacing the original twin panels. This refurbishment standardised the nose end appearance, though not all early locomotives received the modification. From the mid-1970s onward, a more dramatic change emerged: plated-over nose ends with sealed beam headlights. This modification removed the four-character headcode panels entirely, installing sheet metal and larger, flatter profile marker lights.

The Class 46's decline began earlier than most contemporary diesels. The introduction of High Speed Trains (HSTs) on main routes from 1982 eliminated traditional locomotive-hauled express passenger services. Reduction of traditional freight traffic flows and delivery of new freight locomotives (Classes 56 and 58) removed freight work. Increasing maintenance costs, particularly addressing bogie cracking issues, made older Type 4s uneconomical compared to the massive Class 47 fleet.

Fleet

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Withdrawal and Preservation Legacy

The withdrawal history of the British Rail Class 46 reflects the rapid transformation of BR's diesel fleet as HSTs revolutionised express passenger services and modern freight locomotives displaced first-generation types. 46003 (D140) became the first withdrawal in October 1978 after just 16 years 11 months service due to collision/fire damage. Intensive withdrawals began in July-December 1980 with thirteen locomotives condemned, and the last five locomotives officially withdrew on 25 December 1984, ending regular Class 46 service.

Only three Class 46 locomotives survived from the original 56, representing a mere 5.4% survival rate—the lowest among the Peak classes (Class 44: 20%, Class 45: 8.7%). This rarity resulted from rapid withdrawal timing in 1984, immediate scrapping at Swindon and Doncaster Works through 1985, and the less-developed state of diesel preservation in the early 1980s compared to steam.

46010 (D147) nearly missed preservation entirely, languishing at Doncaster Works for nearly three years in increasingly forlorn condition. A comprehensive two-year restoration by Pioneer Diesels (2017-2019) included complete cab rebuilds with new framework and plating, bodyside reskinning, full cab rewiring, and replacement of insulation with fireproof materials. The locomotive rolled out in December 2018 and currently operates in BR Blue livery at Great Central Railway (Nottingham).

46035 "Ixion" (D172), saved by departmental service as 97403, entered Pete Waterman's collection after 1990 withdrawal. Its February 1994 certification for main line operation represented a pioneering achievement in diesel preservation. The locomotive operated numerous main line railtours through the 1990s and early 2000s, including the Severn-Tyne Express and Royal Edinburgh. Now based at Peak Rail, Rowsley, Derbyshire, it wears BR Green with late crest and is currently stored pending future plans.

46045 (D182) represents the most active survivor, saved through departmental service as 97404. Owned by the Peak Locomotive Company Limited and based at Midland Railway - Butterley, it's frequently hired to other heritage railways for extended periods and diesel galas. A major overhaul completed in October 2020 refitted the generator, turbocharger, and intercoolers, with repainting into BR Blue with full yellow cab front. The locomotive retains an operational steam heating boiler—a valuable asset for heritage railway winter services.

The most famous Class 46 working occurred on 17 July 1984 at the Old Dalby Test Track when 46009 (D146) was deliberately crashed at approximately 100 mph into a nuclear waste flask to demonstrate no radioactive leak would occur in a rail accident. The spectacular collision—broadcast publicly and now famous footage—completely destroyed 46009, which was scrapped on-site. This dramatic test ensured 46009 became the most famous Class 46 in popular culture despite its violent destruction.

Modelling Significance and Scale Replications

The BR Class 46 presents exceptional modelling significance due to its transitional position in British railway history—bridging the optimistic 1960s diesel modernisation through to the HST revolution of the 1980s. The distinctive visual evolution from BR green with grey stripe through multiple Rail Blue configurations, combined with famous workings like the china clay trains and Trans-Pennine expresses, creates modelling opportunities satisfying both historical authenticity and operational variety.

Bachmann Branchline has produced the Class 46 since 1994, with progressive upgrades maintaining market relevance. The original 1994 release featured a CAN motor and DCC compatibility without a socket. The 2003 upgrade added an 8-pin DCC socket, while the current specification from 2009 provides a 21-pin DCC socket, making decoder installation straightforward. Current models in the 32-series represent mature, reliable OO gauge products benefiting from three decades of tooling refinement.

Current Bachmann models include 32-702A (D138) in BR Green with small yellow panels at approximately £142-150 street price, 32-702ASF with factory-fitted DCC sound, 32-704 (46045) in BR Blue weathered finish with sealed beam headlights, and 32-700Z (97403 'Ixion') in BR Research Division departmental livery. Technical specifications include a 5-pole motor with twin flywheels, both bogies powered, and separately fitted detail parts including cab handrails, windscreen wipers, lamp brackets, and sandpipes.

Quality assessments note older models (1990s catalog numbers) suffered from noisy running and gear problems, but current 21-pin versions receive praise for good detail, reliable running, decent pulling power, and straightforward DCC installation. The models serve as popular weathering subjects, with Key Model World featuring a detailed weathering article demonstrating authentic Gateshead depot filthy condition.

The game-changing development comes from Rapido Trains UK, which launched a comprehensive Class 46 range in 2024 for delivery in 2025. This premium N gauge series includes seven versions covering the locomotive's full history: 948201 (D140) in 1961 all-over green, 948202 (D182) in BR Green with small yellow panels, 948203 (D138) in BR Green with full yellow ends, 948204 (46026 'Leicestershire and Derbyshire Yeomanry') in BR Blue with headcode blinds, 948205 (46037) in BR Blue with domino headcodes, 948206 (46010) in BR Blue with sealed beam headlights, and 948207 (97403 'Ixion') in RTC Blue/Red departmental livery.

All Rapido versions feature Next18 decoder sockets with pre-fitted speakers, providing straightforward DCC sound installation. The 948701-948707 series offers factory-fitted DCC sound versions. Technical specifications include high-quality coreless motors, all-wheel drive and pickup, etched metal grilles, separately fitted handrails and wipers, directional lighting with working headcode panel illumination, and NEM standard coupling pockets. Development used shared tooling and research with Rapido's acclaimed Class 44 and 45 models, capturing subtle differences between locomotives depending on era.

Pricing runs £144.95 RRP for DCC Ready (street price £123.20 with typical 15% discount) and £249.95 RRP for DCC Sound Fitted. Pre-orders are available from Rapido Trains UK, Rails of Sheffield, and Kernow Model Rail Centre, with delivery expected through 2025. The Rapido range's comprehensiveness covers every significant livery variation and operational period, providing modellers with unparalleled choice for authentic period modelling.

No manufacturer produces Class 46 models in O gauge (7mm scale), representing the most significant market gap. Heljan manufactures Class 45 in O gauge but offers no Class 46 versions. Kit availability proves equally limited, with PD Marsh Models offering only an N gauge conversion/detail kit. This represents a significant opportunity for kit manufacturers, particularly in O gauge and for detail parts in OO gauge.

Models

Unique Modelling Tips and Layout Integration

Successfully incorporating British Rail Class 46 models into layout operation requires understanding the specialised nature of their prototype duties and the authentic operating scenarios that characterised express passenger and heavy freight work during the 1961-1984 period. Unlike preserved steam or heritage diesel traction suitable for period layouts spanning decades, the Class 46 demands specific 1960s-1980s settings with infrastructure, rolling stock, and operational practices reflecting the transition from first-generation diesels to HSTs.

Authentic operating scenarios should reflect the diverse roles Class 46s fulfilled. Midland Main Line and cross-country services employed 8-12 coach formations during the 1960s-early 1970s using Mk1 coaches in maroon livery. Typical consists mixed FK (First Corridor), BSK (Brake Second Corridor), TSO (Tourist Second Open), plus RMB/RB (Restaurant/Buffet cars). The blue/grey livery officially introduced on 1 January 1965 gradually replaced maroon, with transition complete by 1974—providing clear visual markers for era-appropriate modelling.

The most distinctive and model-worthy Class 46 freight working involved the "clay hoods"—china clay trains from Cornwall to Stoke-on-Trent. During the pre-1980s period, these employed OOV/UCV wagons (wooden construction with tarpaulin "hood" covers) in various shades of blue. Typical consists ran 15-30+ wagons in block trains, later transitioning to PRA "Clay Tigers" air-braked bogie wagons. For modellers, a Class 46 hauling 20-25 blue OOV wagons on a West Country to Midlands route represents one of the most authentic and visually distinctive scenarios possible.

Era selection proves crucial for authentic Class 46 representation. 1960s scenarios (1961-1969) demand a Gateshead-allocated Class 46 in BR green with grey stripe and small yellow warning panels hauling 8-10 maroon Mk1 coaches on Liverpool-Newcastle expresses, heavily weathered with fuel staining and exhaust marks. 1970s scenarios (1970-1979) suit Class 46s in Rail Blue livery hauling 20-30 OOV/UCV clay hood wagons from Cornwall to the Midlands, or Trans-Pennine services with 7 Mk2 coaches in blue/grey.

Early 1980s scenarios (1980-1984) should feature summer Saturday holiday trains—the Class 46's final passenger glory. A worn Rail Blue Class 46 hauling mixed Mk1/Mk2 blue/grey coaching stock on Newcastle-Plymouth or Bradford-Weymouth services captures this period, with heavy weathering appropriate to declining maintenance standards. The final regular passenger workings occurred in summer 1984 on these Saturday holiday services before withdrawal in November-December.

Depot scenes offer excellent static display opportunities. Typical depot facilities included fueling points, wheel lathes and lifting jacks for bogie changes, engine removal facilities at main depots like Laira, and steam heating boiler maintenance equipment. For 1984-1985 modelling, withdrawn Class 46s stored at Swindon Works, Derby Works, or Doncaster Works awaiting scrapping provide atmospheric scenes of an ending era, illustrating the rapid changeover to HSTs and Class 47 domination.

Sound-equipped models benefit from careful attention to the Class 46's distinctive operational characteristics. The Sulzer 12LDA28-B engine created particular exhaust patterns—deep bass rumble at idle, sharp acceleration bark as power increased, and steady rhythmic beats during running. Programming sound decoders to emphasise these characteristics through appropriate volume levels and timing creates authentic atmosphere. The vacuum exhausters produced distinctive hissing, while the Stone-Vapor steam heating boiler added its own characteristic sounds during winter operations.

Finally

The British Rail Class 46 represents far more than 56 modestly-numbered diesel locomotives; these machines embodied a critical transition point in British railway history when BR tested electrical equipment alternatives that would shape diesel traction for decades. Samuel Brush's electrical equipment, validated through Class 46 service experience, directly enabled the Class 47's success—Britain's most numerous and longest-lived diesel class with 512 units operating into the 21st century.

For railway historians, the class provides fascinating insights into the practical realities of diesel modernisation during a period of rapid technological evolution and operational experimentation. The decision to build just 56 locomotives with Brush equipment, then cancel the final 20 to enable competitive bidding for a refined design, demonstrates BR's pragmatic approach to diesel development. The Class 46's relatively brief 23-year service career proved the concept whilst avoiding over-commitment to a transitional design.

The tragic rarity of preserved examples—only three survivors from 56 built, representing just 5.4% survival—makes the class particularly precious. The timing of final withdrawals on Christmas Day 1984 preceded the preservation movement's full maturity, whilst the unglamorous mixed-traffic role lacked the glamour that attracted early preservationists focused on named expresses and exotic hydraulics. This makes contemporary heritage railway operations by 46010, 46035, and 46045 particularly valuable, providing modern enthusiasts opportunities to experience these distinctive Peak variants in action.

Model railway enthusiasts find in the Class 46 an ideal subject balancing historical significance with practical modelling opportunities. Bachmann's mature OO gauge range provides reliable, detailed models benefiting from three decades of progressive refinement, whilst Rapido Trains UK's comprehensive seven-variant premium N gauge series launching 2025 represents the cutting edge of small-scale British diesel modelling. The variety of liveries and modifications offers endless possibilities for authentic recreation spanning 1961-1984.

Whether representing early 1960s express passenger services in BR green with maroon coaches, the iconic 1970s china clay trains with blue hood wagons, or final 1984 summer Saturday workings in faded Rail Blue, these models bring character and authenticity to any period-appropriate British layout. The emphasis on authentic heavy weathering—reflecting depot practice where mechanical excellence coexisted with external neglect—gives modellers license to create realistically grimy locomotives that capture the working reality of BR diesels during the pre-privatisation era.

As the railway preservation movement continues evolving and new generations discover the fascination of first-generation diesel operations, the British Rail Class 46 stands as the perfect exemplar of transitional technology—sophisticated enough to handle premier services yet supplanted by more refined successors when HSTs revolutionised British railways. These machines prove that engineering significance emerges not always from longevity or numbers built, but from enabling the next generation of technology that follows.

Frequently Asked Questions

How many British Rail Class 46 locomotives were built and when?

Fifty-six Class 46 locomotives comprised the complete fleet, all constructed at Derby Works between 1961 and 1963. They were numbered D138-D193 in the pre-TOPS era, later renumbered 46001-46056 under the Total Operations Processing System introduced in the early 1970s. The build divided into batches with different headcode panel configurations, with D138-D173 receiving two-aspect panels and D174-D193 featuring four-aspect panels from new.

What made the Class 46 different from the Class 45?

The Class 46 used Brush electrical equipment (TM73-68 main generator and six TM64-68 traction motors) whilst the otherwise identical Class 45 employed Crompton Parkinson electrical systems. Both used the same Sulzer 12LDA28-B intercooled diesel engine producing 2,500 bhp and shared the distinctive 1Co-Co1 wheel arrangement. The electrical equipment difference extended to cab controls, with Class 46 master controllers matching Classes 31 and 47 design rather than the Class 45's Crompton Parkinson layout.

Why were Class 46s withdrawn so early compared to Class 47s?

Multiple factors contributed to Class 46 withdrawal by Christmas Day 1984 after just 23 years service. The introduction of High Speed Trains from 1982 eliminated traditional locomotive-hauled express passenger services on main routes. The massive Class 47 fleet (512 locomotives) provided overwhelming economies of scale in spare parts and maintenance expertise compared to just 56 Class 46s. Persistent bogie cracking problems increased maintenance costs, whilst reduction in traditional freight traffic and delivery of new Classes 56 and 58 removed remaining duties.

What were the famous "clay hoods" trains?

The "clay hoods" were specialised china clay trains from Cornwall to the Staffordshire Potteries at Stoke-on-Trent that became the signature Class 46 freight working. These long-distance block trains hauled 15-30+ OOV/UCV wagons (wooden construction with tarpaulin "hood" covers in various blue shades) and later PRA "Clay Tigers" air-braked bogie wagons. This distinctive working became so associated with Class 46s that it represents an essential modelling scenario for enthusiasts seeking authentic operations.

How many Class 46 locomotives were preserved?

Only three Class 46 locomotives survived from the original 56 built, representing a mere 5.4% survival rate—the lowest among the Peak classes. The survivors are 46010 (D147) at Great Central Railway (Nottingham), 46035 "Ixion" (D172) at Peak Rail, Rowsley, and 46045 (D182) based at Midland Railway - Butterley. The rarity resulted from rapid withdrawal timing in 1984, immediate scrapping at Swindon and Doncaster Works, and the less-developed state of diesel preservation compared to the 1990s onwards.

What OO gauge Class 46 models are currently available?

Bachmann Branchline produces OO gauge Class 46 models with current versions featuring 21-pin DCC sockets for straightforward decoder installation. Available models include 32-702A (D138) in BR Green with small yellow panels, 32-702ASF with factory-fitted DCC sound, 32-704 (46045) in BR Blue weathered finish with sealed beam headlights, 32-704SF with factory sound, and 32-700Z (97403 'Ixion') in BR Research Division departmental livery. Street prices typically run £142-150 for DCC Ready versions and £217-225 for sound-fitted models with standard retail discounts.

Are Class 46 models available in N gauge?

Rapido Trains UK launched a comprehensive Class 46 range in 2024 for delivery in 2025, representing the most detailed and accurate N gauge British diesel models produced. Seven versions cover the locomotive's complete history from 1961 all-over green through various BR Blue configurations to the RTC departmental livery, including the only named example 46026 'Leicestershire and Derbyshire Yeomanry'. All versions feature Next18 decoder sockets with pre-fitted speakers, with DCC Ready models at £144.95 RRP and DCC Sound Fitted at £249.95 RRP.

What coaching stock should I use with Class 46 models?

For authentic 1960s-early 1970s consists, use 8-12 BR Mk1 coaches in maroon livery (1956-1974) mixing FK (First Corridor), BSK (Brake Second Corridor), TSO (Tourist Second Open), plus RMB/RB (Restaurant/Buffet cars). The blue/grey livery introduced 1 January 1965 gradually replaced maroon through 1974. For 1970s-1980s Trans-Pennine services, 7 early Mk2 coaches in blue/grey livery authentically represent Liverpool-York-Newcastle routes. The progression from maroon Mk1 through blue/grey Mk1 to Mk2 coaches provides clear visual markers for era-appropriate modelling.

What was the significance of 46009's nuclear flask crash test?

On 17 July 1984 at the Old Dalby Test Track, 46009 (D146) was deliberately crashed at approximately 100 mph into a Flatrol wagon carrying an empty nuclear waste flask to demonstrate no radioactive leak would occur in a rail accident involving nuclear waste transport. The spectacular collision—broadcast publicly and now famous footage—completely destroyed 46009, which was scrapped on-site by Vic Berry of Leicester the same month. This dramatic test ensured 46009 became the most famous Class 46 in popular culture despite its violent destruction.

Did Class 46s operate on the Western Region?

Yes, a major fleet reorganisation occurred in 1969-1971 as BR withdrew aging hydraulic diesels on the Western Region. The December 1969 winter timetable saw Class 46s working through to Penzance without locomotive changes at Bristol. By 1971, Bristol Bath Road received Nottingham's Class 46 allocation, Laira (Plymouth) gained significant numbers, and some went to Cardiff Canton. These Western Region locomotives received GWR-pattern AWS/ATC equipment in the early 1970s before WR routes converted to BR-pattern for HST introduction.

Why should Class 46 models be heavily weathered?

Period accounts emphasise that "a filthy Peak hauling maroon Mk 1 coaches was the universal symbol of express passenger working" with clean examples "a rare sight," reflecting "official indifference to external condition despite mechanical excellence." Gateshead depot locomotives particularly exemplified grimy appearance throughout the 1960s-1970s. For modellers, heavily weathered models accurately represent typical service condition rather than neglect—focus on fuel staining, exhaust marks, brake dust, heavy frame grime, and oil leaks around engine room grilles for authentic appearance.

What's the 1Co-Co1 wheel arrangement?

The 1Co-Co1 arrangement comprises six powered axles in two three-axle bogies (Co-Co) with unpowered pony trucks at each end (the "1" designations). This configuration solved BR's strict 20 long tons maximum axle loading requirement by distributing the 135-tonne locomotive weight across eight axles instead of six. The pony truck bogie design borrowed from Southern Railway locomotives 10201-10203 provided superior weight distribution, enhanced riding quality at speed, and better tracking through curves compared to simpler Co-Co configurations used by later classes.

How did the Class 46 enable the Class 47's success?

The Class 46 served as the testbed for Brush electrical equipment that would power Britain's most successful diesel class. After ordering 56 Class 46 locomotives, the BTC cancelled the final 20 units and invited competitive bids for a new Type 4 specification using the Brush equipment intended for those cancelled locomotives. Brush Traction won this contract using equipment validated by Class 46 service experience, resulting in the Class 47 with 512 units built operating successfully for over 40 years. In this sense, every Class 47 validates the engineering choices that made the limited Class 46 fleet worthwhile.