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GWR 4575 Class
GWR 4575 Class
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GWR 4575 class
4598 at Swindon Works in 1954
Type and origin
Power typeSteam
DesignerCharles Collett
BuilderGWR Swindon Works
Order numberLots 242, 249, 251, 253
Build date1927–1929
Total produced100
Specifications
Configuration:
 • Whyte2-6-2T
 • UIC1′C1′ h2t
Gauge4 ft 8+12 in (1,435 mm) standard gauge
Leading dia.3 ft 2 in (0.965 m)
Driver dia.4 ft 7+12 in (1.410 m)
Trailing dia.3 ft 2 in (0.965 m)
Minimum curve5 chains (330 ft; 100 m) normal,
4.5 chains (300 ft; 91 m) slow
Wheelbase26 ft 10 in (8.18 m)
Length36 ft 4+12 in (11.09 m) over buffers
Width8 ft 9 in (2.667 m)
Height13 ft 0 in (3.962 m)
Axle load15 long tons 11 cwt (34,800 lb or 15.8 t)
(17.4 short tons) full
Adhesive weight46 long tons 5 cwt (103,600 lb or 47 t)
(51.8 short tons) full
Loco weight61 long tons 0 cwt (136,600 lb or 62 t)
(68.3 short tons) full
Fuel typeCoal
Fuel capacity3 long tons 14 cwt (8,300 lb or 3.8 t)
Water cap.1,300 imp gal (5,900 L; 1,600 US gal)
Firebox:
 • Grate area16.6 sq ft (1.54 m2)
BoilerGWR Standard No. 5[1]
Boiler pressure200 lbf/in2 (1.38 MPa)
Heating surface:
 • Firebox94.25 sq ft (8.756 m2)
 • Tubes992.51 sq ft (92.207 m2)
Superheater:
 • Type4-element or 6-element
 • Heating area4-element: 52.98 sq ft (4.922 m2),
6-element: 69.84 sq ft (6.488 m2)
CylindersTwo, outside
Cylinder size17 in × 24 in (432 mm × 610 mm)
Valve gearStephenson
Valve typePiston valves
Train brakesVacuum
Performance figures
Tractive effort21,250 lbf (94.5 kN)
Career
OperatorsGWR » BR
Class4575
Power classGWR: C,
BR: 4MT
Number in class100
Numbers4575–4599, 5500–5574
NicknamesSmall Prairie
Axle load classGWR: Yellow
Withdrawn1956–1964
Preserved4588, 5521, 5526, 5532, 5538, 5539, 5541, 5542, 5552, 5553, 5572
Disposition11 preserved, remainder scrapped

The Great Western Railway (GWR) 4575 Class is a class of 2-6-2T British steam locomotives.

History

[edit]

They were designed as small mixed traffic branch locomotives, mainly used on branch lines. They were a development of Churchward's 4500 Class with larger side tanks and increased water capacity.[2] 100 were built numbered 4575–4599 and 5500–5574. 15 (Nos. 4578/81/89, 5511/24/29/34/35/45/55/59/60/68/72/74) were fitted with auto apparatus in 1953 to enable them to run push-pull trains on South Wales lines with auto trailers.[2]

They often are referred to as Small Prairie Class tank locomotives.

Table of orders and numbers[3]
Year Quantity Lot No. Locomotive numbers Notes
1927 30 242 4575–4599, 5500–5504
1927 20 249 5505–5524
1928 20 251 5525–5544
1928–29 30 253 5545–5574

Preservation

[edit]

11 members of the class have been preserved:

Number and name Home Status Image
4588 Peak Rail Has run in preservation,[when?] but currently out of service requiring overhaul.[as of?] It was sold from the Dartmouth Steam Railway in 2015 and is now owned by Mike Thompson and based at Peak Rail.[4]
5521/L.150 Epping Ongar Railway[5] Built in 1927, withdrawn by BR[year needed] and sent to Woodham Brothers scrapyard, having run just over 1,000,000 miles (1,600,000 km). Saved with classmates 4561 and 5542 by the West Somerset Railway Association, but was sold with 5542 to repay purchase debts and to fund restoration of 4561. Bought by Richard and William Parker in 1980, it was restored at the Flour Mill, Forest of Dean from 2004 to 2007. It was featured in the 2007 Wolsztyn Parade,[6] then travelled to Budapest, Hungary where it worked intermittently with MAV Nosztalgia, including piloting the Orient Express. It returned to Poland in 2008, operating suburban services from Wroclaw to Jelcz Laskowice. After a third appearance at the 2009 Wolsztyn Parade, it was returned to England. In May 2013, it was painted in London Transport livery and numbered L.150 to commemorate the 150th anniversary of the Metropolitan line. Returned to traffic in 2021 following overhaul.[7]
5526 South Devon Railway On loan to the Gwili Railway.[as of?] Boiler ticket expires in 2027.
5532 Llangollen Railway Under restoration.[8][as of?]
5538 The Flour Mill, Forest of Dean, Gloucestershire Under restoration.[as of?] Previously displayed in Barry Island.[9][until when?]
5539 Barry Tourist Railway Under restoration.[as of?] Previously part of the Barry Ten until 2006.[10]
5541 Dean Forest Railway Currently operational as of 2023. Boiler ticket expires in 2024.[11]
5542 South Devon Railway Currently under overhaul at the South Devon Railway.[as of?] This locomotive has visited several preserved railways throughout her preservation career.[12]
5552 Bodmin and Wenford Railway Returned to service in 2023 after overhaul, having previously run from 2003 to 2013.[13]
5553 Peak Rail Owned by Pete Waterman. Last steam engine to leave Woodham Brothers scrapyard in Barry, Vale of Glamorgan, South Wales, in January 1990. First resteamed in 2002, running until 2012, mostly at the West Somerset Railway. Moved in 2015 from Crewe Heritage Centre for overhaul, which was completed in 2021 at Peak Rail. Currently operational, boiler ticket expires 2031.
5572 Didcot Railway Centre On static display awaiting overhaul.[14][as of?]

Two members of the class have also briefly been out on the mainline: 5521 and 5572. 5521 was shipped to Poland in 2007 to take part in the Wolsztyn Parade, as well as briefly piloting the Orient Express. 5572 made an appearance at an open day in Reading as part of the GWR 150 celebrations in 1985, arriving under its own power. When returning to Didcot again under its own power the engine also hauled the replica broad gauge locomotive "Iron Duke" alongside the preserved GWR Railcar W22W.[citation needed]

Models and toys

[edit]

Lima made a model[when?] of the 4575 class, number 4589, in GWR green, also a British Railways black-liveried version, running number 5574. Bachmann Branchline have for many years[when?] made various versions of the 4575 Class.

See also

[edit]

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
The GWR 4575 Class is a class of 2-6-2T ("") side-tank steam locomotives designed by and built by the Great Western Railway (GWR) at between 1927 and 1929, with a total of 100 locomotives constructed (numbered 4575–4599 and 5500–5574). Developed as an improved version of the earlier , the 4575 Class featured larger side tanks with sloping tops for increased water capacity (1,300 imperial gallons), 4-foot-7.5-inch driving wheels, outside cylinders measuring 17 by 24 inches, and a boiler operating at 200 psi, delivering a of 21,250 lbf. These modifications enhanced their suitability for mixed-traffic duties on branch lines, particularly in the hilly regions of Wales and the , where they hauled passenger trains of up to 11 coaches and freight services, including assistance on expresses like the Cambrian Coast Express and . The class had power class C under the GWR and 4MT under British Railways, weighed approximately 61 tons, with a of 36 feet 4.5 inches and an output of around 850 horsepower. Many were fitted with auto-train apparatus for push-pull operations in , and fitted with with piston valves for efficient performance. Withdrawals began in April 1956 with locomotive No. 4586, and the last active examples were retired in December 1964 following the end of steam operations on British Railways. Notable for their reliability and versatility, 11 locomotives from the class have been preserved, including No. 5572 at (the sole survivor with original auto-gear intact) and No. 5542 at the South Devon Railway, allowing continued operation on heritage lines today.

Design and Development

Background and Origins

The Great Western Railway (GWR) faced significant expansion challenges following the 1923 Grouping, which integrated numerous smaller railways into its network, necessitating versatile locomotives for secondary and operations across and the . In response, Chief Mechanical Engineer initiated designs for improved mixed-traffic engines to handle the increased demands without the limitations of tenders. The 4575 Class emerged in 1927 as Collett's development of George Churchward's earlier 4500 Class "Small Prairie" 2-6-2T locomotives, incorporating enlarged side tanks with sloping tops to boost water capacity from approximately 1,000 imperial gallons in the predecessor to 1,300 imperial gallons. This enhancement allowed for extended runs on rural routes while maintaining the compact footprint suitable for tight curves and sidings. Designed primarily for duties, the class enabled efficient hauling of heavier freight and passenger loads—up to 11-coach trains—on secondary routes, providing rapid acceleration and reliability without requiring water stops as frequently as tender engines. The initial order comprised 25 locomotives numbered 4575–4599, soon expanded to a total of 100, including the later batch 5500–5574, to meet GWR's growing operational needs in the late .

Technical Specifications

The GWR 4575 Class was a development of the earlier 4500 Class, featuring modifications such as larger side tanks with sloping tops to increase water capacity while retaining the core for mixed-traffic duties on branch lines. Key engineering features included two outside cylinders measuring 17 inches in diameter by 24 inches in stroke, fitted with piston valves and for efficient steam distribution. The utilized the GWR Standard No. 5 , which operated at a working pressure of 200 psi and incorporated elements; the firebox provided 94.25 square feet of heating surface, with tubes contributing 992.51 square feet and the 73.8 square feet, yielding a total heating surface of approximately 1,160 square feet (1,087 sq ft evaporative plus 73.8 sq ft ) and a grate area of 16.6 square feet. This configuration delivered a of 21,250 lbf at 85% pressure, suitable for hauling typical branch-line trains.
SpecificationDetails
Wheel arrangement2-6-2T
Driving wheel diameter4 ft 7½ in
Leading/trailing wheel diameter3 ft 2 in
Cylinder dimensions17 in × 24 in (two outside)
Valve typePiston valves
Boiler type
Boiler pressure200 psi
Firebox heating surface94.25 sq ft
Total heating surface~1,160 sq ft (including )
Grate area16.6 sq ft
Tractive effort
Length over buffers36 ft 4½ in
Water capacity1,300 gallons
Coal capacity3 tons 14 cwt
Locomotive weight61 tons
The locomotives were equipped with vacuum brakes for both train and engine control, compatible with GWR passenger and goods stock, and used a screw-type reverser for precise regulation of steam cutoff. These features contributed to the class's reliability and versatility in secondary services.

Construction and Production

Building Program

The GWR 4575 Class locomotives were constructed entirely at the Great Western Railway's , with all 100 units produced between 1927 and 1929. Building on the design principles established by Chief Mechanical Engineer , the class utilized standardized GWR components such as boilers and frames to streamline assembly and ensure consistency across the fleet. Production was divided into four lots: Lot 242 in 1927 (Nos. 4575–4599 and 5500–5504, totaling 30 locomotives), Lot 249 later in 1927 (Nos. 5505–5524, 20 locomotives), Lot 251 in 1928 (Nos. 5525–5544, 20 locomotives), and Lot 253 spanning 1928–1929 (Nos. 5545–5574, 30 locomotives). This batching allowed for efficient manufacturing, with an approximate output of 30–40 locomotives per year, reflecting Swindon's capacity for rapid yet methodical of tank engines. The use of interchangeable parts from existing GWR designs minimized custom fabrication, enabling workers to assemble frames, cylinders, and tanks with precision using jigs and templates developed at . This approach not only controlled expenses but also supported the railway's expansion needs in the late . Upon completion, each underwent rigorous and testing at Swindon's stationary testing plant, a facility operational since 1904. New builds were placed on the plant's braked rollers to evaluate pressure, consumption, drawbar pull, and wheel balance at equivalents up to 70 mph (around 400 rpm), ensuring reliability before entry into service. These procedures, overseen by Swindon's engineering teams, verified adherence to Collett's specifications and identified any assembly issues, contributing to the class's reputation for robust performance from the outset.

Modifications and Variants

During their service life, members of the GWR 4575 Class received several post-construction modifications to improve operational flexibility and efficiency, though the class as a whole avoided major rebuilds. In , fifteen locomotives were fitted with auto-brake equipment to enable push-pull operation with autotrailers, particularly on branch lines in ; examples include Nos. 5526, 5537, 5542, 5546, 5553, 5563, 5568, and 5572, which facilitated driver-only working without needing to run around at terminals. Some units also received enlarged coal bunkers during overhauls, raising capacity from the standard 3 long tons to approximately 4 long tons in select cases to extend range on remote duties without frequent refueling. During , the class adhered to standard GWR wartime adaptations, such as dimmed or shielded lighting fixtures and enforced speed restrictions to minimize visibility risks during blackouts, ensuring continued use on essential freight and passenger services amid resource constraints.

Operational History

Great Western Railway Service

The GWR 4575 Class locomotives were designed for versatile mixed-traffic operations on the Great Western Railway's branch lines, where they primarily handled local passenger services, light freight trains, and shunting duties across rural and semi-rural networks. Their compact size and balanced design made them ideal for the shorter distances and frequent stops typical of these routes, allowing efficient performance without the need for turning facilities at many terminals. These engines were allocated to several key depots in the Western Region, including near for suburban and branches, in for southern routes, and for maintenance and local operations. Other significant sheds included Laira in Plymouth, Bristol Bath Road, and Welsh locations such as and , reflecting their widespread deployment to support regional traffic demands. By the end of 1947, just prior to , allocations showed a concentration in the southwest and , with examples like No. 4575 at and No. 4576 at . Notable routes served by the class encompassed the undulating branch lines of and , where they were favorites for local passenger and goods workings; the challenging Welsh valleys, including services from depots like Tondu and Treherbert; and extensions into the , such as lines around to . In these areas, the locomotives navigated tight curves and moderate gradients effectively, contributing to the GWR's reputation for reliable secondary services. In terms of performance, the 4575 Class proved reliable for branch line speeds reaching up to 60 mph between stations, enabling timely passenger runs while maintaining stability on routes with varying gradients. Their enlarged side tanks supported extended operations without frequent watering stops, enhancing efficiency for mixed duties that often involved up to 11 coach passenger trains or equivalent freight loads on lighter sections.

British Railways Era

Upon nationalisation in 1948, the GWR 4575 Class locomotives were allocated to the British Railways Western Region, continuing their roles on former GWR routes with minimal initial changes to their operational patterns. They saw heavy use on coal traffic, with numerous examples based at sheds such as Ebbw Junction, Aberbeeg, and Tondu, where they handled busy freight workings amid the region's industrial demands. Allocations also included key depots like and for service on the lines, supporting passenger and mixed traffic duties during the peak of the 1950s. Some locomotives assisted on named expresses, such as the Cambrian Coast Express to and parts of the . The class reached its zenith in the early , with all 100 locomotives in service by August 1950, deployed across branch lines in , the , and the . However, the introduction of diesel multiple units and broader modernisation efforts led to a decline, with duties reduced by the mid- as branch lines faced closures or conversions. Withdrawals commenced in April 1956, starting with locomotives like 4586, as competition from diesel traction displaced the class from main roles. In their final years, surviving examples were relegated to shunting and short-haul freight tasks, particularly in , with the last eleven in service until 1964. Maintenance continued at into the early 1960s, shortly before the facility ended steam-era activities following the completion of the final BR in 1960.

Withdrawal and Preservation

Withdrawal Process

The withdrawal of the GWR 4575 Class locomotives commenced in 1956 with No. 4586, initiating a phased decommissioning under British Railways as steam operations faced mounting pressures. The process gained momentum in the early 1960s, influenced by the Beeching Report of 1963, which prompted extensive closures that diminished the demand for these versatile tank engines on secondary routes. By 1962, the majority had been retired, exemplified by No. 5541's withdrawal in July from Plymouth Laira depot after service on the Launceston branch. The class's operational tenure concluded in December 1964, when the final four locomotives—allocated to depots including and —were taken out of service, following an average lifespan of about 35 years since their between 1927 and 1929. Primary drivers included the widespread dieselization of British Railways' network, which supplanted on both and freight duties, alongside the aforementioned line closures that eroded the class's core workload. The locomotives' advancing age further compounded issues, as deteriorating components, especially boilers, escalated maintenance demands and operational costs. Post-withdrawal, 89 of the 100 locomotives were consigned to scrapping, with many processed at —the historic GWR facility where most had been built—and others at private concerns like Cashmore's yard in Newport, . British Railways maintained detailed records of final examinations, storage periods, and disposals through locomotive stock books and depot logs, ensuring systematic accounting of the class's end.

Preserved Examples

Eleven locomotives from the GWR 4575 Class have been preserved, representing a significant survival rate for the type given the extensive scrapping during the and . These engines were primarily rescued from scrapyard in Barry, , where most arrived after withdrawal by British Railways between the mid- and early , with purchases occurring throughout the and 1970s. The preserved locomotives and their statuses as of November 2025 are:
NumberBuild YearCurrent LocationStatus
45881927Static display
55211928Under restoration
55261928South Devon RailwayAwaiting overhaul
55321928Llangollen RailwayUnder restoration
55381928Static display
55391928Gloucestershire Warwickshire Steam RailwayOperational
55411928Stored, awaiting overhaul (boiler certificate expired December 2024)
55421928South Devon RailwayAwaiting overhaul
55521928Bodmin RailwayOperational
55531928Bodmin Railway (on loan from )Operational
55721929Static display
One prominent example is No. 5542, constructed at in 1928, preserved from Barry in 1975, and restored to working order in 2000. It has served on various heritage lines, including loans to the Warwickshire Steam Railway, but is currently awaiting overhaul at the South Devon Railway as of 2025. Another key survivor is No. 5572, built in 1929 at and acquired from Barry in 1971, now on static display at ; it retains unique auto-train fittings for push-pull operations, the only such example preserved from the class. No. 5541, built in 1928 and saved from Barry in 1972, underwent a major overhaul from 2002 to 2014 at a cost exceeding £120,000 before returning to steam in April 2014. Its boiler certificate expired in December 2024, and it is currently stored at the awaiting overhaul as of 2025. Other preserved members, including Nos. 5552 at Railway and 5553 at Railway (on loan from ), are operational as of 2025 and contribute to tourist operations on these lines, hauling mixed passenger and freight demonstrations. Preservation efforts have faced challenges in sourcing parts, often relying on components from scrapped 4500 Class locomotives due to shared elements like frames and motion, which has enabled restorations despite the age of surviving examples.

Modeling and Replicas

Scale Models

Commercially produced scale models of the GWR 4575 Class are popular among model railroading enthusiasts, particularly in OO, , and O gauges, offering detailed representations suitable for realistic layouts. In (1:76 scale), Bachmann Branchline has produced ready-to-run models since their initial announcement in 2007, featuring accurate Collett-era details such as sloping side tank tops and finely detailed boiler fittings. These models are available in liveries including GWR green with shirtbutton emblems and BR black with early emblems, praised for their smooth running and high-fidelity detailing that captures the locomotive's mixed-traffic branch line heritage. For N gauge (1:148 scale), Dapol offers ready-to-run models released starting in 2006, with DCC compatibility via an 8-pin socket for enhanced operation on compact layouts. These include representations of the 4575 subclass with features like separately fitted handrails, lamp irons, and covers, available in both GWR and BR liveries to reflect the class's operational eras. In O gauge (1:43 scale), Lionheart Trains released ready-to-run models in 2024, featuring detailed representations of the sloping tanks and era-specific fittings. Enthusiasts often turn to kit-built options for greater customization, such as etched brass kits from the range, which provide components for assembling the 4575's distinctive sloping tanks and detailed underframe. These kits emphasize precision for scratch-builders, incorporating whitemetal castings for boiler and cab details, and are typically finished in GWR green or BR black to match preserved examples. Bachmann's OO models have seen ongoing releases, including the 32-115 variant in 2015 equipped with sound functions for immersive play, enhancing the model's appeal for users. Limited editions, such as the Bachmann Collectors Club issue of No. 5553 in BR green with late crest, hold collector value due to their restricted production runs and pristine detailing. Similarly, models depicting preserved No. 5542 in GWR green, like Bachmann's 32-141, are sought after for their historical accuracy and representation of the class's post-war condition.

Toys and Kits

The GWR 4575 Class, known as the Small Prairie tanks, has inspired various simplified toys and construction kits aimed at children and casual hobbyists, focusing on play value rather than precise scaling. These items often feature basic representations of the locomotive's 2-6-2T configuration with side tanks and a trailing wheel, emphasizing imaginative play through assembly or push-along mechanisms. In the mid-20th century, Hornby Dublo produced tinplate die-cast tank locomotives in GWR livery, which were popular in the 1950s for their clockwork or electric operation on simple tracks. These now-vintage pieces, often in green with GWR lettering, have become collectible among enthusiasts for their durable metal construction and nostalgic appeal, originally priced affordably for family budgets. During the 1970s, offered plastic construction kits in , including the 54151 Prairie 2-6-2T Tank Locomotive modeled after the related GWR 61xx Large Prairie class, complete with assembly instructions, molded parts for the boiler, cab, and side tanks, and optional detailing for young builders. These kits encouraged hands-on creativity, with snap-together components suitable for ages 8 and up, and were marketed as educational tools for understanding railway mechanics without requiring advanced tools. Modern wooden train sets draw from GWR tank engine aesthetics, painted in green livery for compatibility with standard wooden tracks. Battery-operated versions of GWR-inspired trains, like those featuring chugging sounds and headlights, provide motorized play for toddlers, typically including a simple oval track and carriages for imaginative scenarios. Educational building kits compatible with LEGO bricks include historical Meccano sets from , produced under Hornby Meccano, allowed adaptation of GWR locomotive designs using metal strips and nuts to construct basic tank engine frames, promoting mechanical experimentation for young inventors. These toys and kits generally target ages 3–12, prioritizing durability, safety, and fun over historical accuracy, with retail prices ranging from £10 for simple wooden push-alongs to £30 for battery-operated or building sets, making them accessible entry points into railway-themed play.

References

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