The British Rail Class 159 represents one of the most successful long-distance diesel multiple unit fleets in modern British railway history. Built as enhanced versions of the ubiquitous Class 158 Express Sprinter, these 22 original three-car units plus eight later conversions have operated continuously since 1993 on the West of England Main Line connecting London Waterloo with Exeter St Davids, Yeovil Junction, and Bristol Temple Meads. Unlike their Class 158 cousins scattered across Britain's regional networks, the Class 159 fleet remains dedicated to South Western services—a remarkable consistency spanning three decades, four operating companies, and ultimately returning to public ownership in 2025.
For model railway enthusiasts, the Class 159 offers compelling prototype appeal: historically significant as Network SouthEast's final new diesel traction order, visually distinctive in its evolution through NSE, South West Trains, and South Western Railway liveries, and blessed with exceptional ready-to-run representation through Bachmann's completely re-tooled range introduced from 2020. The combination of dedicated first-class accommodation, powerful Cummins engines, and three-car formation creates operational characteristics distinctly different from standard Class 158s, providing modellers with authentic long-distance express DMU operations perfectly suited for Waterloo-based layouts.
From replacing unreliable Class 50 locomotives on the challenging West of England route to surviving major incidents including the 2021 Salisbury crash, the Class 159 fleet has demonstrated remarkable resilience and adaptability. The units continue earning their keep hauling packed commuter services, holiday traffic to the West Country, and everything in between—with no confirmed replacement date despite approaching 35 years of intensive service. This longevity creates excellent modelling opportunities across multiple eras whilst remaining thoroughly relevant for contemporary layout operation.
Quick Takeaways
- 22 original units built: Bodyshells constructed at BREL Derby 1989-1992 as Class 158s, then converted to Class 159 specification by Babcock Rail at Rosyth Dockyard 1992-1993
- Enhanced Express Sprinter specification: Dedicated first-class accommodation with 2+1 seating, more powerful 400hp Cummins NTA855-R3 engines (versus 350hp in Class 158), and retention toilets for long-distance comfort
- Three-car formation standardisation: Every unit configured as DMCL-MSL-DMSL with all three vehicles powered, enabling flexible coupling into 6-coach, 8-coach, or 9-coach formations for peak demands
- Single-route dedication: Exclusively operated London Waterloo to Exeter St Davids/Bristol Temple Meads services since 1993 introduction, never deployed elsewhere despite privatisation and franchise changes
- Eight additional conversions: Class 159/1 units (159101-159108) created 2006-2007 by converting surplus Class 158s, retaining original 350hp R1 engines but otherwise identical
- Return to public ownership: Fleet transferred to DfT Operator Limited on 25 May 2025, becoming Britain's first nationalised passenger service under 2024 legislation whilst retaining South Western Railway branding
- Bachmann exclusive models: Completely re-tooled OO gauge range from 2020 features dual motorisation, Plux22 DCC sockets, factory sound options, and exceptional interior detail representing pinnacle of RTR DMU production
Historical Background and Context
The genesis of the Class 159 project emerged from an unusual administrative circumstance during the final years of British Rail's unified existence. In the late 1980s and early 1990s, Regional Railways had embarked on an ambitious programme of Class 158 Express Sprinter procurement to replace aging first-generation diesel multiple units across Britain's secondary routes. The ordering process, conducted during a period of rapid organisational change and uncertain privatisation planning, resulted in Regional Railways commissioning more Class 158 units than immediately required for their allocated routes.
Simultaneously, Network SouthEast faced an acute motive power crisis on the prestigious West of England Main Line services connecting London Waterloo with Exeter St Davids via Salisbury. The route had relied on Class 50 diesel locomotives hauling Mark 2 coaching stock since the late 1970s, but by the early 1990s these locomotives—built between 1967-1968 for express passenger duties—had reached the end of their economically viable service lives. Chronic reliability problems, expensive maintenance requirements, and increasingly frequent failures created operational chaos disrupting the vital link to Britain's South West peninsula.
British Rail's solution demonstrated the pragmatic flexibility still possible within the unified national railway before privatisation fragmented decision-making. Network SouthEast agreed to accept 22 surplus Class 158 bodyshells from Regional Railways' over-ordering, but insisted on comprehensive specification upgrades transforming them into dedicated long-distance express units suitable for the demanding West of England services. The modifications would create a distinct new class incorporating lessons learned from early Class 158 operations whilst meeting NSE's specific requirements for comfort, performance, and operational flexibility.
The contractual arrangements, however, proved complex. British Rail Engineering Limited at Derby Litchurch Lane Works had constructed the 22 bodyshells between 1989-1992 as standard Class 158 components. BREL's impending privatisation created complications regarding warranty obligations and specification modifications, with the newly-independent company reluctant to undertake extensive conversion work on units it considered complete to original contract specifications. After considerable negotiation, British Rail awarded the conversion contract to Babcock Rail at Rosyth Dockyard in Scotland—an unusual choice reflecting both BREL's contractual position and Babcock's competitive pricing for the modification programme.
Insider Tip: Identifying Class 159 versus Class 158
Distinguishing Class 159 from standard Class 158 requires attention to subtle external details alongside formation differences. The most reliable recognition feature remains the three-car formation—Class 159 exclusively operates as three-car sets, whilst Class 158 predominantly runs as two-car units. Internal arrangements differ significantly: Class 159 features dedicated first-class accommodation with distinctive 2+1 seating, whilst Class 158 offers only standard class or declassified space. The bodyside vents and grilles show identical patterns, making livery and route knowledge crucial for positive identification. For modellers recreating authentic consists, remember that Class 159 units couple together or with Class 158/170 using BSI couplers, creating mixed formations during peak traffic periods.
Rosyth Dockyard commenced conversion work during 1992, implementing four fundamental modifications distinguishing Class 159 from standard Class 158 specification. First, dedicated first-class accommodation replaced standard-only seating in one section of each unit, featuring higher-quality 2+1 transverse seating compared to standard class 2+2 arrangements. Second, retention toilet systems replaced the simpler chemical toilets fitted to Class 158, addressing environmental concerns and providing more pleasant facilities for the longer-distance West of England journeys.
Third, and most significantly for operational performance, Babcock replaced the original Cummins NTA855-R1 engines producing 350 horsepower with uprated NTA855-R3 variants generating 400 horsepower. This 14% power increase provided substantially improved acceleration and hill-climbing capability essential for the challenging West of England route featuring numerous steep gradients including the notorious Honiton Bank. The additional power enabled units to maintain schedules with heavier loadings whilst providing capacity for future service improvements.
Fourth, the conversion programme installed a sophisticated four-step braking system incorporating rheostatic braking alongside conventional air and electro-pneumatic systems. This advanced braking technology provided superior deceleration performance and reduced brake block wear, though the unique implementation initially prevented multiple-working compatibility with other Sprinter variants—a limitation subsequently resolved through control system modifications enabling mixed formations with Class 158 and Class 170 units.
The first completed unit, 159004, transferred from Rosyth to Network SouthEast on 6 January 1993, marking the beginning of intensive driver training and route familiarisation. The remaining 21 units followed progressively through spring 1993 as Babcock completed conversions and delivery logistics. Network SouthEast branded the new fleet as the "South Western Turbo," emphasising both the turbocharger technology and the service acceleration compared to locomotive-hauled trains. Revenue service commenced on 10 June 1993, with the Class 159 fleet progressively replacing Class 50 operations as more units entered traffic and driver training expanded.
Contemporary railway press coverage praised the new units' comfort, performance, and reliability. Passengers particularly appreciated the dedicated first-class accommodation, improved ride quality compared to locomotive-hauled stock on the sometimes rough West of England track, and the elimination of locomotive run-rounds at Exeter enabling faster turnaround times. The operational flexibility of three-car units coupling into 6-coach formations for peak services whilst separating for off-peak economy impressed railway managers facing tight budget constraints.
Design and Technical Specifications
The engineering excellence of the British Rail Class 159 derives from the proven Class 158 platform enhanced through carefully selected specification upgrades addressing long-distance express operation requirements. At the heart of each three-car unit sit three Cummins NTA855-R3 turbocharged diesel engines—one per vehicle—each producing 298 kW (400 hp) at 2,100 rpm. This configuration delivers total unit power of 895 kW (1,200 hp), substantially greater than the 783 kW available from standard Class 158 installations using the lower-rated R1 engine variant.
The Cummins NTA855 engine represents mature, proven technology refined through decades of railway, marine, and industrial applications. The designation indicates a 14-litre displacement six-cylinder inline diesel with turbocharger and aftercooler. Two-stage turbocharging provides excellent power density whilst maintaining acceptable fuel consumption and emissions performance for early 1990s standards. The R3 variant fitted to Class 159/0 units incorporates uprated internal components enabling sustained 400 hp output compared to the 350 hp R1 specification—a critical advantage for maintaining schedules on demanding gradients with full passenger loads.
Power transmission follows the Voith hydraulic system widely adopted across British Rail's second-generation DMU fleet. Each engine drives a Voith T211r/rz three-stage hydraulic transmission incorporating torque converter, three forward speeds, and reverse. The transmission connects to a final drive unit distributing power to both axles of each powered bogie through cardan shafts and axle-mounted gearboxes. This proven mechanical arrangement delivers smooth acceleration, excellent low-speed control for station work, and reliable performance across the operating speed range.
The bogie design utilises BREL's standard patterns developed for the Sprinter family. Powered vehicles ride on BREL P4-4A bogies incorporating traction motors, whilst the single trailer vehicle in early design iterations (subsequently all vehicles were motorised) employed BREL T4-4A trailer bogies. Both designs feature coil spring primary suspension and air spring secondary suspension, providing excellent ride quality across the speed range whilst accommodating the significant unsprung mass of traction equipment. The wheelbase measures 2.6 metres within each bogie, with bogies positioned 15.5 metres apart creating overall vehicle lengths of approximately 23 metres.
The bodyshell construction employs welded aluminium alloy throughout, providing excellent corrosion resistance whilst minimising weight compared to steel alternatives. This lightweight construction proves particularly valuable for powered DMUs where power-to-weight ratio directly affects acceleration performance and fuel efficiency. The distinctive Sprinter profile features large windows creating bright, airy passenger accommodation, whilst the angular nose design with central coupling position provides excellent forward visibility for drivers.
Formation arrangement designates vehicles as DMCL (Driving Motor Composite Lavatory), MSL (Motor Standard Lavatory), and DMSL (Driving Motor Standard Lavatory). The DMCL vehicle accommodates 23 first-class passengers in 2+1 transverse seating plus 39 standard-class passengers in 2+2 seating, with retention toilet facilities at the non-driving end. The centre MSL vehicle provides 70 standard-class seats and toilet facilities. The outer DMSL vehicle offers 37 standard-class seats plus toilet facilities and driving cab. This arrangement totals 23 first-class and 146 standard-class seats per three-car unit, with two wheelchair spaces and comprehensive accessibility features.
Technical Innovation: The Four-Step Braking System
The Class 159's sophisticated braking system incorporates rheostatic braking alongside conventional air and electro-pneumatic systems, creating what railway engineers term "four-step" braking. Rheostatic braking converts traction motors into generators during deceleration, dissipating kinetic energy as heat through roof-mounted resistor grids. This technology reduces brake block wear, improves passenger comfort through smoother deceleration, and enables sustained speed control on long descents without overheating conventional brakes. The system initially prevented multiple-working with Class 158 units due to control compatibility issues, but subsequent modifications resolved these limitations. For modellers, the roof-mounted rheostatic grids provide subtle recognition features distinguishing Class 159 from Class 158 when viewed from elevated positions.
Multiple working capability enables operational flexibility essential for varying traffic demands. Units couple using BSI autocouplers at outer ends incorporating pneumatic, electrical, and through-gangway connections. Up to three Class 159 units can operate in multiple (nine coaches total), creating substantial capacity for peak holiday traffic to the West Country. Additionally, Class 159 units couple and work in multiple with Class 158 and Class 170 Turbostar units, enabling mixed formations and operational flexibility when unit availability fluctuates due to maintenance requirements.
The maximum speed rating of 90 mph (145 km/h) matches standard express DMU practice and proves entirely adequate for West of England Main Line services where infrastructure constraints, frequent stops, and single-track sections limit sustained high-speed running. The power-to-weight ratio enables brisk acceleration from station stops, crucial for maintaining schedules on a route featuring numerous intermediate stations interspersed with challenging gradients including Honiton Bank's 1-in-80 climb.
Safety systems incorporate Train Protection & Warning System (TPWS) providing automatic brake application when approaching signals at danger, Automatic Warning System (AWS) alerting drivers to adverse signal aspects and speed restrictions, Driver's Safety Device (DSD) ensuring driver vigilance, and comprehensive fire detection and suppression systems throughout passenger and technical spaces. Modern refurbishments added CCTV coverage, passenger information systems, and accessibility enhancements meeting contemporary standards.
Service History and Operations
The British Rail Class 159 fleet entered service gradually during summer 1993 as units completed driver training requirements and route familiarisation. The first revenue service occurred on 10 June 1993 when unit 159004 worked the morning London Waterloo to Exeter St Davids service, marking the beginning of what would become an unbroken three-decade association between these distinctive DMUs and the West of England route. Network SouthEast's branding as "South Western Turbo" emphasised both the modern turbocharged technology and the substantial service improvements these units delivered compared to aging Class 50 locomotive-hauled trains.
Initial operations concentrated on the principal London Waterloo to Exeter St Davids services via Salisbury, Yeovil Junction, and Honiton. The 171-mile journey typically required three hours including intermediate stops at major stations. Units operated in coupled pairs (six coaches) during peak periods, splitting at Salisbury with one three-car portion continuing to Exeter whilst the other worked local services or returned to London. This operational pattern maximised capacity on the busy London-Salisbury corridor whilst providing economical single-unit operation on the less intensively used Salisbury-Exeter section.
The fleet quickly demonstrated substantial advantages over predecessor Class 50 locomotive operations. Elimination of locomotive run-rounds at Exeter and other termini saved 10-15 minutes per journey, enabling improved frequency and better resource utilisation. The multiple-unit configuration allowed flexible capacity adjustment matching traffic demands—six coaches for peak commuter services, nine coaches for Friday afternoon West Country holiday traffic, three coaches for quieter off-peak periods. Passengers appreciated the modern accommodation, particularly the dedicated first-class sections offering genuine long-distance comfort compared to declassified Mark 2 stock.
Reliability proved generally excellent following initial teething troubles. The proven Cummins engines and Voith transmissions required less maintenance than aging Class 50 locomotives, whilst the distributed power arrangement meant single-engine failures rarely caused service cancellations—units could limp home on two engines if necessary, albeit with reduced performance. The hydraulic transmission occasionally proved troublesome in extremely cold weather, but overall availability rates substantially exceeded Class 50 figures, pleasing both operators and passengers.
Operational Insight: The Salisbury Split Pattern
The characteristic Class 159 operating pattern involves units departing London Waterloo coupled in pairs or trios (6-9 coaches), then splitting at Salisbury for separate destinations. One portion continues along the West of England Main Line to Exeter St Davids, possibly extending to Exeter Central or Exmouth. The other portion either works Bristol Temple Meads services via Westbury, operates local Salisbury area stopping trains, or returns empty to London for peak return services. This sophisticated splitting pattern requires precise timekeeping and crew coordination but maximises capacity utilisation across varying demand patterns. For modellers recreating authentic operations, Salisbury station becomes the critical location requiring sufficient platform length for coupled formations plus points enabling separation and independent departure.
Privatisation on 4 February 1996 transferred the fleet to Stagecoach Group's South West Trains franchise. The transition proceeded smoothly, with Stagecoach initially retaining NSE livery before progressively applying its corporate blue and red colour scheme from 1997 onwards. The first major refurbishment occurred during 2000-2001 when all units received interior retrimming with new seat moquette, upgraded lighting, and SWT external livery. This programme cost approximately £1 million per unit but substantially improved passenger environment and extended economic service life.
A second comprehensive refurbishment during 2007-2008 cost £2.8 million per unit and addressed accessibility legislation alongside customer experience improvements. Modifications included CCTV installation throughout passenger saloons, electronic Passenger Information Systems with next-stop announcements, upgraded first-class seating with increased legroom and individual reading lights, power sockets at selected seats, and distinctive orange door surrounds improving accessibility identification. These modifications transformed 1990s rolling stock into thoroughly contemporary accommodation meeting 21st-century passenger expectations.
The second Class 159 variant emerged during 2006-2007 when Wabtec Doncaster converted eight surplus Class 158 units into Class 159/1 specification. Units 159101-159108 joined the SWT fleet following the same conversion process pioneered at Rosyth 15 years earlier, though these conversions retained original Cummins NTA855-R1 engines producing 350 hp rather than receiving R3 upgrades. The lower power output proved acceptable given strengthening service patterns enabling more economical operation with reduced performance margins. These eight additional units provided valuable capacity as traffic levels increased beyond original 22-unit fleet capability.
Franchise change on 20 August 2017 transferred operations to South Western Railway—a joint venture between FirstGroup (70%) and MTR Corporation (30%). The new operator commenced progressive livery renewal applying an attractive blue, white, and red scheme celebrating both the South Western heritage and modern corporate identity. Units received interior cleaning and minor refurbishment, though no fundamental mechanical changes occurred. The Class 159 fleet continued operating identical service patterns under new management and branding.
A serious incident occurred on 31 October 2021 when unit 159102 collided with Great Western Railway Class 158 units 158864 and 158952 at Fisherton Tunnel Junction approaching Salisbury. The accident resulted from signal passing at danger (SPAD), with the Class 159 striking stationary GWR units from behind. Miraculously, no fatalities occurred despite significant vehicle damage. Unit 159102 suffered structural damage beyond economic repair, with vehicles 57803 and 58703 scrapped in January 2023 and DMCL 52803 following in March 2025. This reduced the operational fleet from 30 to 29 units—the only Class 159 withdrawal to date.
The most recent operational change occurred on 25 May 2025 when services transferred to DfT Operator Limited (DFTO) following the Passenger Railways Services (Public Ownership) Act 2024. South Western Railway became Britain's first nationalised train operating company since privatisation, though the SWR brand continues in use under public ownership. The Class 159 fleet maintains identical operational patterns under this new ownership structure, continuing three decades of unbroken service on West of England routes.
Current operations deploy the 29-unit fleet across core services: London Waterloo to Exeter St Davids (principal route, typically 6-9 coach formations splitting at Salisbury), London Waterloo to Bristol Temple Meads via Westbury (some services), Salisbury area local services including connections to Southampton and Portsmouth, and various peak-hour commuter workings. Units based at Salisbury Traincare Depot receive maintenance ranging from daily servicing through heavy overhauls, with the facility having maintained Class 159 units since 1993 introduction.
Despite approaching 32 years since original entry to traffic (35 years for the bodyshells), no confirmed replacement date exists. The fleet received comprehensive refurbishments extending service life, whilst the relatively modest annual mileage compared to intensively-used suburban DMUs suggests further years of operation remain economically viable. Industry observers speculate that new rolling stock might arrive during the late 2020s or early 2030s, but budget constraints and competing priorities suggest Class 159 operations continuing well into the current decade.
Withdrawal and Preservation Legacy
The withdrawal history of the British Rail Class 159 remains remarkably brief given 32 years of intensive service—only one unit has faced premature retirement, whilst the remaining 29 continue daily revenue operations with no confirmed end date. This extraordinary longevity reflects both the fundamental soundness of the Sprinter platform and the substantial investment in progressive refurbishment programmes extending economic service life far beyond original expectations.
Unit 159102 represents the sole casualty, withdrawn following catastrophic damage in the Salisbury rail crash of 31 October 2021. The collision with stationary Great Western Railway Class 158 units at Fisherton Tunnel Junction caused structural damage to all three vehicles beyond economic repair given the unit's age and the cost of comprehensive rebuilding. Vehicle 57803 (DMSL) and 58703 (MSL) were scrapped at Eastleigh Works in January 2023, whilst vehicle 52803 (DMCL) lingered until March 2025 before final disposal. No components were salvaged for other units, and no preservation society expressed interest in acquiring the damaged vehicles for static display or potential restoration.
The remaining fleet shows no immediate withdrawal prospects despite increasing age. The comprehensive 2007-2008 refurbishment costing £2.8 million per unit delivered effectively rebuilt interiors meeting contemporary accessibility and passenger comfort standards. The mechanical condition remains generally sound, with Cummins engines capable of substantial further service given appropriate maintenance. The aluminium bodyshells show minimal corrosion compared to steel-bodied contemporaries, whilst progressive component replacement during routine overhauls continuously renews the fleet.
Several factors conspire to delay Class 159 replacement. The relatively modest fleet size (29 units) makes bespoke new rolling stock procurement economically challenging—manufacturers demand larger orders to justify tooling costs, whilst off-the-shelf alternatives like Class 769 bi-mode conversions prove unsuitable for the non-electrified West of England route. The units' moderate annual mileage compared to intensively-used suburban fleets reduces wear and tear, extending viable service life. Most significantly, chronic budget constraints facing both franchised operators and the nationalised successor make expensive rolling stock replacement difficult to justify whilst existing units remain serviceable.
Preservation's Uncertain Future
No Class 159 units currently reside in preservation, though several factors suggest eventual preservation remains likely once withdrawals commence. The class represents the final diesel multiple unit design built for Network SouthEast, making units historically significant as markers of the Sectorisation era. The three-decade dedication to West of England services creates strong regional identity and affection. The sophisticated specification including first-class accommodation, powerful engines, and advanced braking systems demonstrates British Rail's technical capabilities during the pre-privatisation period. However, preservation faces challenges: the three-car formation demands substantial covered accommodation, the complex mechanical systems require specialist maintenance expertise, and competition from more glamorous steam locomotives and early diesel types may divert limited preservation resources. Realistically, preservation of one or two units seems probable once withdrawals commence, though comprehensive fleet preservation appears unlikely.
Industry speculation regarding replacement focuses on several possible scenarios. The most likely involves cascade of newer DMU classes from electrification schemes releasing diesel units from other operators—though matching capacity and performance proves challenging. Alternative proposals include bi-mode (diesel-electric) units enabling operation under wires on the Waterloo-Basingstoke section whilst continuing diesel operation beyond, though the substantial infrastructure investment required for Waterloo area electrification makes this scenario increasingly unlikely given budget constraints.
A radical alternative suggests complete route electrification using overhead equipment, enabling operation of modern electric multiple units with superior performance and lower operating costs compared to diesel traction. However, the substantial civil engineering challenges including numerous Victorian-era tunnels with restricted clearances, the extensive single-track sections requiring comprehensive signalling renewal, and the eye-watering cost estimates approaching £2-3 billion make full electrification politically difficult despite environmental benefits. The 2040 diesel ban creates pressure for zero-emission traction, but battery technology remains immature for the 171-mile Waterloo-Exeter route.
The most pragmatic projection suggests Class 159 units operating through the late 2020s with progressive withdrawals during the early 2030s as component availability declines and maintenance costs rise. Units approaching 40 years of age will struggle meeting modern accessibility standards despite refurbishment, whilst passenger expectations for Wi-Fi, power sockets, and contemporary comfort features will exceed 1990s-design capabilities. The final units might survive until 2035 if component availability permits, but comprehensive fleet replacement seems inevitable by the mid-2030s.
The engineering legacy extends beyond individual preserved units. The Class 159 validated the Express Sprinter concept for long-distance DMU operation, demonstrating that properly-specified multiple units could match locomotive-hauled comfort whilst offering superior operational flexibility. The dedicated first-class accommodation, powerful engines, and three-car standardisation influenced subsequent DMU procurement including Class 170, Class 180, and Class 185 families. The conversion approach pioneered with Class 159/1 units inspired later projects adapting surplus rolling stock for new purposes rather than expensive new builds.
When final withdrawal occurs, the class will leave a remarkable record: three decades of dedicated service on demanding express routes, successful navigation through privatisation and renationalisation, survival of major incidents, and genuine passenger affection for comfortable, reliable units that made West Country travel genuinely pleasant. This legacy ensures the Class 159 will occupy an honourable place in British railway history regardless of preservation outcomes.
Modelling Significance and Scale Replications
The British Rail Class 159 presents exceptional modelling significance due to its unique position spanning Network SouthEast's final years, the entire privatisation era, and the return to public ownership—all whilst maintaining dedicated service on a single prestigious route. For railway modellers seeking authentic London Waterloo-based operations, Class 159 units provide compelling prototype appeal enhanced by fascinating operational patterns, diverse livery evolution, and genuine long-distance express DMU characteristics distinguishing them from more common Class 158 suburban variants.
The modelling landscape remained dominated by outdated tooling until Bachmann Branchline announced complete re-tooling during 2019 with first deliveries arriving in early 2020. This revolutionary approach abandoned the previous single-motor, basic-detail model in favour of sophisticated new tooling incorporating lessons learned from contemporary European DMU production standards. The investment demonstrated Bachmann's commitment to raising British DMU modelling standards to match the exceptional quality achieved by their Continental counterparts.
Bachmann's new-tooling Class 159 represents what many enthusiasts consider the finest ready-to-run diesel multiple unit ever produced in British OO gauge. Both driving cars feature independent motorisation using low-level mechanisms positioned entirely beneath passenger saloon floors, eliminating the chassis intrusion plaguing earlier DMU models. The sophisticated drive system employs coreless motors, twin flywheels, and all-wheel pickup ensuring smooth operation at prototypical crawling speeds appropriate for station work through sustained high-speed running.
Detail quality throughout the models reaches unprecedented standards for ready-to-run products. Factory-fitted glazing includes comprehensive interior detail with individual passenger seats, luggage racks, toilet compartments, and driving cab equipment visible through windows—all without any chassis components intruding into passenger spaces. Separately applied components include windscreen wipers, door handles, multiple working equipment (MWU) jumper cables, gangway connections, and underframe brake rigging. The bogies accurately represent BREL P4-4A and T4-4A designs with separate brake discs, suspension springs, and traction motor detailing.
The electrical specification proves equally impressive. Each driving car incorporates a Plux22 decoder socket positioned in the roof space, enabling straightforward DCC installation without requiring body removal or difficult soldering. Factory speakers mount in optimised positions for sound decoder installation, with resonance chambers enhancing audio quality. Sound-fitted versions feature Zimo MX645P22 decoders with authentic Class 159 sound recordings including Cummins engine notes, Voith transmission whine, horn, door sounds, and comprehensive lighting effects.
The lighting implementation deserves particular praise. Directional LED headlights, tail lights, and cab lights operate automatically under DCC control, whilst the destination indicators incorporate day/night switching—displaying illuminated destinations during dark hours and black-on-white displays during daylight. This sophisticated feature accurately replicates prototype behaviour and demonstrates exceptional attention to operational realism. Additional lighting includes marker lights, cab interior illumination, and saloon lighting visible through windows creating thoroughly convincing night-time operation.
Current production focuses on two principal liveries. Catalogue number 31-520 represents unit 159013 in Network SouthEast "Revised" livery—the predominantly white colour scheme with blue and red stripes introduced during NSE's final years. This livery suits layouts depicting 1993-1996 operations under British Rail or early South West Trains franchise period. The DCC Ready version retails at £249.99, whilst sound-fitted variant 31-520SF commands £329.99—competitive pricing given the exceptional quality and comprehensive feature set.
The exclusive Kernow Model Rail Centre variant depicts unit 159016 in contemporary South Western Railway blue, white, and red livery. Catalogue numbers 31-520Z (DCC Ready, £459.95 RRP) and 31-520ZSF (Sound Fitted, £559.95 RRP) released during December 2022/January 2023 enable modellers to represent current operations under nationalised ownership. The KMRC exclusive features "London Waterloo" destination displays and represents Era 11 (2022-present) specification including all recent detail refinements.
Advanced Modelling: Sound Decoder Programming
Bachmann's factory-fitted Zimo MX645P22 sound decoder offers exceptional customisation possibilities for advanced modellers. The decoder features 28 function outputs enabling control of lights, sounds, and motorised effects through DCC function mapping. Authentic Class 159 sounds include start-up sequence, idle running, acceleration through eight notch positions, deceleration, brake squeal, door opening/closing, horn, and station announcements. The lighting effects include directional headlights, tail lights, cab lights, saloon lights, and destination indicator day/night switching. Advanced users can adjust sound volumes, modify lighting brightness, programme alternative horn sequences, and create custom function mappings matching personal preferences. The comprehensive Zimo documentation enables expert modellers to extract maximum realism from already exceptional factory specification.
Earlier Bachmann tooling remains available through the secondary market, though the quality gap compared to new models proves substantial. The original 31-510NSE depicting unit 159001 "City of Exeter" in Network SouthEast livery dates from approximately 1998 and features single driving car motorisation, basic interior detail with visible chassis intrusion, no DCC socket, and protruding LED headlights. The subsequent 31-512 representing unit 159009 in South West Trains livery (circa 2005) shares identical mechanical specification with updated livery application. These models typically command £100-150 on the pre-owned market—substantial savings versus new tooling, though the functionality and detail compromises prove significant.
N gauge enthusiasts face more challenging prospects. Graham Farish produced Class 159 models using the standard Sprinter tooling shared across Class 156/158/159 variants, but all versions now show discontinued status with availability limited to remaining dealer stock and secondary market. Catalogue number 371-526 depicting South West Trains livery represents later production (approximately 2010-2015) with DC-only operation and no DCC socket provision. The earlier 8748 in Network SouthEast livery dates from original 1994 tooling and features similarly basic specification.
Pre-owned N gauge Class 159 models typically command £50-100 depending on condition and livery, though finding specific units requires patience and diligent searching across online auctions and specialist dealers. The lack of DCC-ready specification proves limiting for modellers operating digital layouts, though skilled installers can retrofit miniature decoders with considerable effort. The basic detail quality and simplified interior appointments reflect 1990s-2010s N gauge production standards—adequate for operational layouts but lacking the sophistication contemporary modellers expect.
No other manufacturers—Hornby, Dapol, Heljan, Accurascale, Revolution Trains, Realtrack Models, Oxford Rail, or Rapido Trains UK—produce or have announced Class 159 models in any scale. Bachmann's Branchline and Graham Farish brands hold exclusive production rights across both OO and N gauge, making them the sole source for ready-to-run Class 159 representation. This exclusivity creates certainty for procurement planning but limits competitive pressure encouraging continual improvement.
O gauge modellers face complete absence of commercial products. No manufacturer produces ready-to-run, kit, or craftsman-quality Class 159 models in 7mm scale, and none have announced development plans. The substantial market size required to justify O gauge tooling combined with the class's relatively modest enthusiast following compared to steam locomotives or iconic diesel types makes commercial production unlikely. Skilled scratchbuilders can construct Class 159 models using architectural aluminium profiles and etched brass detailing, though this approach demands advanced modelling capabilities and substantial time investment.
Livery availability in model form remains limited compared to the prototype's diversity. The three commercially produced liveries—Network SouthEast Revised, South West Trains blue/red, and South Western Railway blue/white/red—represent the most significant schemes, but several important variants remain unmodelled. The original Network SouthEast "Jaffa Cake" livery with orange stripe worn 1993-1995 has never appeared in model form. The South West Trains "Express" variant with orange door surrounds introduced during 2007-2008 refurbishment remains unavailable despite representing a decade of operation. These gaps frustrate modellers seeking specific period representation.
The secondary market occasionally offers custom-painted variants or weathered models, though prices vary wildly depending on execution quality. Professional painting services can apply alternative liveries to Bachmann models, typically charging £150-250 for complete three-car unit refinishing including lining, lettering, and weathering. This approach enables representation of specific units or experimental liveries, though the cost approaches or exceeds purchasing additional factory-finished models.
Unique Modelling Tips and Layout Integration
Successfully incorporating British Rail Class 159 models into layout operation requires understanding the specialised nature of their prototype duties and the authentic operating scenarios that characterised West of England express services during the 1993-present period. Unlike ubiquitous Class 158 units scattered across Britain's regional networks, Class 159s demand specific route context and operational patterns for convincing representation. The dedicated service profile creates both challenges and opportunities for modellers committed to authentic recreation.
Layout design should reflect the West of England Main Line's distinctive characteristics. The route features a mix of double-track main line (London Waterloo to Basingstoke), single-track sections with passing loops (particularly beyond Salisbury), and challenging gradients including the notorious Honiton Bank requiring substantial power for heavily-loaded units. Station platforms must accommodate coupled formations—minimum six coaches (two three-car units), ideally nine coaches (three units) for peak period representation. Salisbury emerges as the critical location requiring complex trackwork enabling splitting/joining operations plus adequate platform length for coupled formations.
Authentic operating scenarios reflect the class's express passenger role. Typical workings include London Waterloo departures at approximately hourly intervals during daytime, operating as 6-9 coach formations to Salisbury where units split for separate destinations—one portion continuing to Exeter St Davids (171 miles, approximately 3 hours), another working Bristol Temple Meads via Westbury, or returning to London. This sophisticated splitting pattern creates engaging operational interest whilst accurately representing prototype practice. Off-peak periods see single three-car units working the complete route, reflecting reduced demand outside commuter peaks and summer holiday periods.
Era selection proves fundamental for authentic Class 159 representation. Network SouthEast period layouts (1993-1996) demand NSE livery with the distinctive "Jaffa Cake" orange stripe or later Revised white-based scheme, appropriate infrastructure including NSE station signage and colour schemes, and contemporary coaching stock including Class 442 Wessex Electric and Class 50/Mark 2 formations during the transition period. South West Trains era (1996-2017) enables the blue/red livery with optional Express variant featuring orange doors from 2007, SWT infrastructure branding, and Class 444/450 Desiro electric units sharing Waterloo operations. South Western Railway period (2017-present) showcases current blue/white/red livery, contemporary infrastructure including digital information displays, and Class 701 Aventra electric units.
Weathering Authenticity for Express DMU Service
Class 159 weathering should reflect long-distance express operation with regular depot attention but inevitable accumulation of road grime and operational wear. Focus weathering effects on operational areas: rail dust along solebar edges particularly behind bogies, brake dust on wheel faces and lower bodysides, exhaust staining around roof-mounted vents from Cummins diesel engines, buffer beam weathering from coupling operations, and general road dirt accumulated during 171-mile journeys. However, avoid heavy industrial weathering inappropriate for passenger-rated units receiving daily cleaning at Salisbury Traincare Depot. The aluminium bodyshells resist corrosion, making rust effects inappropriate except on steel components including bogies and underframe equipment. Windscreen weathering including bug strikes and wiper marks adds realism. The roof equipment shows heavier weathering from exhaust deposits and weather exposure. First-class accommodation windows might appear cleaner than standard class, reflecting more frequent interior servicing.
Train formations should match prototype practice and operational period. Single three-car units represent off-peak or outer-suburban services, appearing regularly beyond Salisbury where traffic density reduces. Six-coach formations (two coupled three-car units) characterise typical daytime London-Salisbury services with adequate capacity for commuter and leisure traffic. Nine-coach formations (three coupled units) appear during peak commuter periods, Friday afternoon West Country holiday traffic, and summer weekend services when demand peaks. Mixed formations with Class 158 or Class 170 units occasionally occur, reflecting operational flexibility when unit availability fluctuates due to maintenance requirements.
Station stopping patterns recreate authentic service characteristics. London Waterloo departures typically call at Clapham Junction, Woking, Basingstoke, Overton, Whitchurch, Andover, Salisbury (splitting point), Gillingham, Templecombe, Sherborne, Yeovil Junction, Crewkerne, Axminster, Honiton, and Exeter St Davids—approximately 15 intermediate stops over 171 miles creating average speeds around 55 mph including dwell time. Some services omit minor stations, creating semi-fast variants. Bristol services diverge at Salisbury via Westbury and Frome, featuring different calling patterns. Local services around Salisbury operate truncated routes with more frequent stops.
Operational sessions benefit from varied duties reflecting typical Class 159 deployment. A realistic operating sequence might begin with a London departure coupled in pairs (six coaches), splitting at Salisbury with one portion continuing to Exeter whilst the other works Bristol Temple Meads, both portions returning independently to London at different times, perhaps coupling at Salisbury for the return journey depending on timing. This pattern creates engaging operational challenges requiring precise timekeeping, careful coordination of splitting/joining procedures, and realistic shunting movements.
Sound-equipped models enhance operational realism through authentic audio experiences. The distinctive Cummins NTA855 diesel engine note differs markedly from other DMU types, creating characteristic sound signatures during acceleration and sustained running. Programme sound decoders to emphasise realistic operational sequences: start-up procedure including turbocharger spooling, gentle idling at stations with door sounds, progressive acceleration through transmission notches, sustained running at line speed, engine braking during deceleration, and air brake sounds during station approaches. The horn operates automatically at level crossings (numerous on the West of England route) and when departing stations.
Infrastructure authenticity demands attention to period-specific details. Overhead electrification equipment appears only on the London Waterloo to Basingstoke section, with Class 159s operating under wires but drawing no power. Semaphore signals survived on some secondary sections until the 2000s, progressively replaced by colour-light installations. Level crossings feature prominently throughout the route, many still protected by traditional gates or barriers. Station architecture ranges from Victorian grandeur at Salisbury and Exeter to modest country stations on intermediate sections. The single-track sections beyond Salisbury feature passing loops with token exchange equipment (progressively replaced by Radio Electronic Token Block systems).
Depot scenes provide excellent static display opportunities. Salisbury Traincare Depot has maintained the Class 159 fleet since 1993, with facilities including fueling points, carriage washing plants, maintenance workshops, and component stores. Units typically stable overnight between diagrams, creating opportunities for displaying multiple units in depot settings. Interior cleaning, minor repairs, and routine servicing occur daily, whilst heavier maintenance requires units to enter covered workshops. Depot staff figures add life—cleaners, mechanics, and supervisors engaged in daily activities maintaining the fleet.
Timetable construction should reflect express service characteristics. Class 159 units typically complete two or three return trips daily between London and West of England destinations, with substantial layover periods at terminals enabling cleaning, fuelling, and minor maintenance. Unlike intensive suburban operations requiring rapid turnarounds, express services allow more leisurely preparation between diagrams. This operational rhythm suits modellers preferring quality over quantity—fewer but longer-distance trains rather than constant suburban shuttle operations. The sophisticated Salisbury splitting pattern creates operational interest without overwhelming controllers.
Finally
The British Rail Class 159 represents far more than 30 three-car diesel multiple units; these machines embody the final flowering of Network SouthEast's investment in quality express traction, the remarkable resilience of well-specified rolling stock, and the enduring appeal of dedicated route identity in an era of standardisation. From their unconventional genesis—surplus Class 158 bodyshells transformed through Babcock Rail's Rosyth conversions—through three decades of reliable West of England service, the Class 159 fleet has consistently exceeded expectations whilst maintaining genuine passenger affection.
For railway historians, the Class 159 story illuminates several important themes. The pragmatic approach of converting over-ordered Class 158 bodyshells rather than designing entirely new units demonstrated British Rail's resourcefulness during the chaotic pre-privatisation period. The specification upgrades—dedicated first-class, powerful engines, sophisticated braking—proved that thoughtfully-enhanced standard designs could match bespoke express units at fraction of the cost. The sustained single-route operation spanning 32 years and counting provides fascinating counterpoint to the fragmentation and frequent redeployments characterising most DMU fleets during privatisation and subsequent restructuring.
The technical specification validated several important design principles. The three-car formation standardisation enabled flexible capacity adjustment through multiple working whilst maintaining economical single-unit operation during off-peak periods. The distributed power arrangement with one engine per vehicle provided excellent redundancy—single-engine failures rarely caused service cancellations. The hydraulic transmission, despite occasional cold-weather difficulties, delivered smooth acceleration and reliable performance across demanding gradients. The dedicated first-class accommodation demonstrated that DMUs could provide genuine long-distance comfort rivalling locomotive-hauled stock.
The longevity achievement proves particularly remarkable. Units approaching 32 years since entry to traffic (35 years for the bodyshells) continue daily express operations with no confirmed replacement date, testament to both sound original engineering and comprehensive refurbishment programmes extending economic service life. The 2007-2008 rebuilds costing £2.8 million per unit delivered effectively new interiors meeting contemporary standards whilst the proven mechanical components continue reliable service with appropriate maintenance. This longevity vindicated British Rail's investment in quality specification over cheap compromise.
Bachmann's exceptional OO gauge range provides model railway enthusiasts with thoroughly authentic West of England express traction featuring unprecedented detail quality and operational sophistication. The complete re-tooling abandoned outdated single-motor compromises in favour of dual motorisation, comprehensive interior detail without chassis intrusion, sophisticated lighting including day/night destination indicators, and factory sound options delivering exceptional realism. The models represent the pinnacle of British RTR DMU production, setting standards that competitors struggle to match.
Model railway hobbyists incorporating Class 159s into London Waterloo-based layouts gain versatile express DMU traction suitable for diverse operational scenarios. The characteristic Salisbury splitting pattern creates engaging operational interest whilst remaining prototypically authentic. The evolution through Network SouthEast, South West Trains, and South Western Railway liveries enables authentic representation across three decades. Whether operating single three-car units on off-peak services or coupled nine-coach formations during summer holiday peaks, Class 159 models bring character and authenticity to any Southern Region-themed layout.
The preservation prospects remain uncertain given the fleet's continued operational status and the challenges of maintaining complex three-car DMUs in heritage settings. However, the historical significance—Network SouthEast's final diesel traction, single-route dedication, technical sophistication—creates compelling preservation case. When eventual withdrawal occurs, likely during the early-to-mid 2030s, preservation of one or two units seems probable despite the substantial resources required. The class deserves representation in the National Collection alongside contemporaries including Class 442 Wessex Electric and Class 50 locomotives, ensuring future generations can appreciate these distinctive express units.
The engineering legacy extends beyond preserved examples. The Class 159 validated the Express Sprinter concept for long-distance DMU operation, demonstrating that properly-specified multiple units offered genuine advantages over locomotive-hauled trains including operational flexibility, elimination of run-rounds, and superior reliability. The conversion approach pioneered with Class 159/1 units inspired later projects adapting surplus rolling stock rather than expensive new builds. The dedicated first-class specification influenced subsequent DMU procurement including Class 170, Class 180, and Class 185 families incorporating similar accommodation standards.
As British railways navigate transition from diesel traction toward zero-emission futures, the British Rail Class 159 stands as exemplar of sustainable rolling stock management—maximising value through progressive refurbishment, maintaining equipment in excellent condition through systematic maintenance, and extending service life far beyond original expectations through thoughtful investment. These principles prove increasingly relevant as budget constraints and environmental imperatives demand alternatives to frequent rolling stock replacement. The Class 159 story demonstrates that properly-maintained equipment can deliver decades of reliable service whilst meeting evolving passenger expectations through comprehensive refurbishment.
The sight and sound of a Class 159 departing London Waterloo—three-car formation accelerating through the Clapham Junction curves, Cummins engines singing, destination indicator proclaiming "Exeter St Davids"—remains one of Britain's most evocative railway experiences. These distinctive units have carried millions of passengers on countless journeys to the West Country, creating memories spanning generations. Long may they continue, and when eventual replacement arrives, may preservation ensure these remarkable express Sprinters remain accessible for future enthusiasts to study, appreciate, and remember.
Frequently Asked Questions
How many British Rail Class 159 units were built and when?
The original Class 159/0 fleet comprises 22 three-car units built 1992-1993. Bodyshells were constructed at BREL Derby Litchurch Lane Works between 1989-1992 as Class 158 components, then converted to Class 159 specification by Babcock Rail at Rosyth Dockyard during 1992-1993. Unit 159004 entered service first on 6 January 1993, with revenue operations commencing 10 June 1993. Additionally, eight Class 159/1 units (159101-159108) were created during 2006-2007 by Wabtec Doncaster converting surplus Class 158 units to similar specification.
What makes Class 159 different from standard Class 158 units?
Class 159 features four key differences: dedicated first-class accommodation with 2+1 seating (Class 158 is standard-only or declassified), more powerful Cummins NTA855-R3 engines producing 400hp versus 350hp R1 engines in Class 158, retention toilet systems suitable for long-distance operation replacing simpler chemical toilets, and a sophisticated four-step braking system incorporating rheostatic braking. Additionally, Class 159 exclusively operates as three-car formations, whilst Class 158 predominantly runs as two-car units.
Where do Class 159 units currently operate?
Class 159 units operate exclusively on South Western Railway services from London Waterloo to Exeter St Davids via Salisbury (principal route), London Waterloo to Bristol Temple Meads via Westbury, and various Salisbury area local services. The fleet has operated these routes continuously since 1993 introduction under Network SouthEast, South West Trains franchise (1996-2017), South Western Railway franchise (2017-2025), and currently under DfT Operator Limited public ownership from 25 May 2025.
Are Class 159 units compatible with other DMU classes for multiple working?
Yes, Class 159 units feature BSI autocouplers enabling multiple working with Class 158 Express Sprinter and Class 170 Turbostar units. Up to three Class 159 units can couple together (nine coaches total), creating substantial capacity for peak services. The sophisticated four-step braking system initially prevented multiple working compatibility but subsequent modifications resolved these limitations. Mixed formations with Class 158 or Class 170 units occur regularly when operational requirements demand.
What is the current operational status of the Class 159 fleet?
29 units remain in active service as of October 2025. The original 22 Class 159/0 units (159001-159022) all remain operational. Of the eight Class 159/1 conversions, seven continue in service whilst unit 159102 was withdrawn following catastrophic damage in the Salisbury rail crash of 31 October 2021. No confirmed replacement date exists, with the fleet expected to continue operating through the late 2020s and potentially into the early 2030s.
What happened to unit 159102?
Unit 159102 was damaged beyond economic repair when it collided with Great Western Railway Class 158 units at Fisherton Tunnel Junction approaching Salisbury on 31 October 2021. The accident resulted from signal passing at danger. Despite significant vehicle damage, no fatalities occurred. Vehicles 57803 and 58703 were scrapped at Eastleigh Works in January 2023, whilst vehicle 52803 followed in March 2025. This represents the only Class 159 withdrawal to date.
What OO gauge Class 159 models are currently available?
Bachmann Branchline produces current-generation Class 159 models with dual motorisation and comprehensive detail. Catalogue 31-520 depicts unit 159013 in Network SouthEast Revised livery (DCC Ready £249.99, Sound Fitted 31-520SF £329.99). Kernow Model Rail Centre exclusives 31-520Z and 31-520ZSF represent unit 159016 in South Western Railway livery (£459.95 and £559.95 respectively). Earlier single-motor tooling (31-510NSE and 31-512) remains available through secondary market at £100-150.
Are Class 159 models available in N gauge or O gauge?
Graham Farish produced N gauge Class 159 models including catalogue 371-526 (South West Trains livery) and 8748 (Network SouthEast livery), but all versions now show discontinued status with availability limited to remaining dealer stock and secondary market at £50-150. No Class 159 models exist in O gauge from any manufacturer, and no O gauge products have been announced. Bachmann/Graham Farish hold exclusive production rights across all scales.
What liveries have been produced in model form?
Three liveries have received commercial production: Network SouthEast Revised white-based scheme (Bachmann 31-520), South West Trains blue and red (Bachmann 31-512 old tooling, Graham Farish 371-526), and South Western Railway blue/white/red (KMRC exclusive 31-520Z). The original NSE "Jaffa Cake" orange stripe livery (1993-1995) and SWT Express variant with orange doors (2007-2017) remain unavailable in model form despite representing significant operational periods.
How should I operate Class 159 models authentically on my layout?
Authentic operation requires London Waterloo to West of England route context with Salisbury as critical splitting point. Operate units coupled in pairs (six coaches) or trios (nine coaches) from London to Salisbury, then split formations with one portion continuing to Exeter St Davids, another working Bristol Temple Meads, or returning to London. Single three-car units represent off-peak services or outer sections beyond Salisbury. The route features mix of double-track and single-track sections with challenging gradients requiring careful speed management.
What features distinguish Bachmann's new-tooling Class 159 from earlier models?
The new tooling features dual motorisation with both driving cars powered using low-level mechanisms, Plux22 DCC decoder sockets in both driving cars, comprehensive interior detail without chassis intrusion, directional LED lighting including day/night destination indicators, factory speaker provision for sound installations, separately applied detailing including wipers and MWU cables, and accurate BREL bogie representation. Earlier single-motor tooling featured visible chassis intrusion, no DCC socket, protruding LED headlights, and simplified detail levels.
Will Class 159 units ever be preserved?
No units currently reside in preservation, though eventual preservation seems likely once withdrawals commence during the early-to-mid 2030s. The class represents Network SouthEast's final diesel traction order, creating historical significance. The dedicated West of England service creates strong regional identity. However, preservation faces challenges including three-car formation demands for covered accommodation, complex mechanical systems requiring specialist expertise, and competition from more glamorous preservation candidates. Preservation of one or two units appears probable despite resource requirements.
Can Class 159 units operate under overhead electrification?
Class 159 units regularly operate under 750V DC third-rail electrification between London Waterloo and Basingstoke but draw no power—they remain diesel-only traction. The units are not bi-mode and cannot draw power from overhead wires. The route beyond Basingstoke remains non-electrified, requiring diesel traction throughout. No plans exist for converting Class 159 units to bi-mode (diesel-electric) operation, with eventual replacement by zero-emission traction considered more economically viable than expensive conversions.