Once the power of the Great Western Railway, the mighty 6000 or King class of 1927 were a series of express passenger locomotives that formed the backbone of passenger trains out of London Paddington and along the core routes to the west of England and the Midlands, becoming the most powerful 4-6-0 steam locomotives ever to operate on Britain’s railways, and truly living up to their names as the monarchs of the permanent way.
The King class was born from necessity, as during 1918, Chief mechanical engineer of the Great Western Railway, George Jackson Churchward, noted that, with the rising demand for fast and lengthy express passenger trains, existing traction for the company would soon not be able to provide the necessary power without requiring the assistance of multiple locomotives, his attention turning firmly to his own premier passenger locomotive for the Great Western, the 4000 or Star class 4-6-0 steam engines of 1906, of which 73 were produced, and proved to be among the most successful passenger locomotives of their day, capable of hauling long and heavy express trains at a top speed of 90mph.
However, as train lengths increased to meet rising passenger numbers, even the venerable Star class was beginning to meet their match when it came to their ability to perform at their fastest speeds, and therefore, Churchward proposed fitting the 6ft diameter boiler used on his brand new 4700 Class 2-8-0, a heavy mixed-traffic locomotive built between 1919 and 1923, and fitting it onto the chassis of a 4-6-0 locomotive to create a more powerful express locomotive, attempting to emulate the performance of Pacific class 4-6-2 locomotives which were being utilised by other British railway companies such as the Great Northern Railway and its upcoming Gresley A1, although his plans were prevented due to a severe 19.5 long-ton weight restriction being present on the Great Western Mainline, particularly on the more remote sections of the route towards Wales and beyond Plymouth to the Cornish towns of Truro and Penzance.
In 1922, Churchward retired at the age of 65, and the role of Chief mechanical engineer was taken over by Charles Benjamin or C.J. Collett, who had joined the Great Western in 1893 and risen through the ranks of the company to Churchward’s deputy in 1919, and chose to continue his predecessor’s incredibly successful legacy of introducing extremely powerful but rugged standard designs that would form the mainstay of the company’s fleet, as well as proving to be far superior to the primary locomotives of the rival British railway firms, and often provided inspiration to their own standardised fleets of engines following the Grouping Act of 1923, which merged many of Britain’s largest railway companies together to form the ‘Big Four’.
Collett’s first move was to create a replacement for the Star Class, which would come to pass as the 4073 or Castle class express passenger trains, taking a leaf from Churchward’s book by taking the basic layout of the Star class and fitting it with an extended frame, and a newly designed No.8 boiler which was both larger and lighter than its predecessor, allowing for an increased amount of steam to be produced that would also permit an enlarged cylinder diameter from 15 in × 26 in to 16 in × 26 in, the extended frame also giving rise to a side window cab and an increased grate area, while giving the Castle class a tractive effort of 31,625 lbs, the resultant machine being a handsome and purposeful looking steam locomotive that was compact enough to remain within the 19.5 long-ton axle limit.
Unveiled in 1923, the Castles were the most powerful steam locomotives at work in the UK at the time, and could power lengthy express passenger trains at speeds of 100mph and more, although due to the design being limited by the maximum axle-loading restriction of the Great Western, these engines would not be able to pull one of the companies regular 13 carriage express trains while meeting the strict and fast paced schedules of the GWR’s top services to Bristol, Birmingham, Wolverhampton, Exeter and Plymouth, the Castle’s eventually losing their title of most powerful steam locomotive in Britain during 1926, following the unveiling of the Southern Railway’s Lord Nelson class, a high speed express passenger engine designed to haul the top-line Boat Trains from London to the Channel ports, and had been the product of Richard Maunsell.
Following the loss of the Castle’s title, the Great Western’s General Manager, Sir Felix Pole, became anxious that the company had lost a certain degree of prestige by the arrival of the Lord Nelson class, and therefore required that a new locomotive be developed in whatever way necessary that would snatch the record back from the Southern Railway, giving Collett approval to explore a potential “Super-Castle” design, on the condition that it would provide a minimum tractive effort of 40,000 lbf, this being combined with a general infrastructure upgrade on the Great Western Mainline, which would see weaker bridges dating back to the Victorian era rebuilt to allow for a general raising of the axle-loading restriction that had so hampered the Castle-class, this being coupled to the findings of the Bridge Stress Committee set up by the Department of Scientific and Industrial Research, which gave engineers a better scientific understanding of the hammer blow effect caused by a vertical force which alternately adds to and subtracts from the locomotive’s weight on a wheel and thereby increases the square of the velocity, the result being that the new Super Castle was permissible to have a maximum axle-loading weight of 22.5 long tons.
While Collett was nominally responsible for the design of the class, the more detailed work was undertaken by his Chief draughtsman, Frederick Hawksworth, with the bulk of the increase in power over the Castle class being initially achieved through raising the boiler pressure to a maximum of 250 pounds per square inch and by increasing the cylinder stroke from 26 in to 28 in, these factors combined pushing up the tractive effort to around 38,165 lbf, which was marginally below the figure of 40,000lbf desired by Pole, further amendments to the design in order to bring it closer to its goal being the adoption of smaller 6 ft 6 in driving wheels with an initial cylinder bore of 16.25-inches, thus providing a further 990 lbf and pushing the tractive effort to 40,300 lbf.
At the same time, the smaller driving wheels had the biproduct of allowing for a wider boiler to be used on the chassis that was more appropriate for use within the loading gauge of the Great Western’s network, although later operational experience showed that the loading gauge clearance of the outer cylinders was problematic, and resulted in their replacement after the locomotive’s first major overhaul that would bring them back down to a regular size, but in so doing reduced the tractive effort of 39,700 lbf, while alongside the various amendments to the locomotive’s width, these engines utilised a brand new 16ft long ‘Standard No.12’ boiler which was unique to the 6000 class, and provided a maximum diameter of 6 feet 0 inches which tapered to 5 feet 6 and a quarter inches, the larger cylinders being accommodated through a distinctive leading bogie design wherein the outside bearings were on the fore wheel and inside bearings on the rear wheel.
In 1927, the Great Western laid down an order for 20 units from their Swindon Works, and in June of the same year, the first example, Number 6000, was released from the factory, followed a month later by five additional units, and the remaining fourteen at weekly intervals between February and July 1928, the weight restrictions of the Great Western still being something of an issue, though, as the locomotives were barred from working outside the two primary mainline routes of the GWR’s network, the line from London Paddington to Wolverhampton Low Level via Banbury, Leamington and Birmingham Snow Hill, and the trunk route to the west and southwest of England, but only as far as Plymouth, as due to the weight limitations of the iconic Royal Albert Bridge across the River Tamar, express trains to Cornwall required the 6000 Class to be swapped out for either a Castle or Hall class at Devonport in order to proceed west across Brunel’s famous structure.
Originally, intentions were for the 6000 class to be named in honour of famous British cathedrals, but during the same year as their unveiling, class premier, number 6000, as part of the centenary celebrations for the Baltimore and Ohio Railway in the USA, was shipped to Maryland at the request of B&O president, Daniel Willard, who had been in contact with Sir Felix Pole and was eager to have one of the Great Western’s locomotives displayed at the celebrations, specifically the upcoming 6000 class, the original schedule being to have the first member of the fleet be delivered in September 1927, but with the B&O centenary event taking place in August, the construction crews at Swindon were able to assemble the locomotive in record time and have it unveiled by the end of June, allowing for the locomotive to be shipped to the United States for the exhibition, the engine being presented with an American-style bell carried over the buffer beam, and the intention of naming the class after Cathedrals was dropped in favour of a moniker that resonated more with an American audience, the number 6000 being christened King George V after the reigning monarch.
Shortly after construction, 6000 travelled to the USA along with the replica broad gauge engine North Star, the boiler being loaded onto the ship separate of the frame as there was no crane available that could lift the whole locomotive as a complete unit, while the appearance of the engine at the Baltimore & Ohio Railway centenary exhibition attracted a quarter of a million visitors during the three weeks it was held, among the visitors who rode on the footplate of the locomotive being Henry Ford, founder of the famous Ford Motor Company and pioneer of the mass-production car which would eventually prove to be the downfall of railways in the coming decades.
Subsequent to 6000’s tour of the USA, the remaining members of the class took the names of British kings in descending order of ascendance to the throne, starting with 6000 King George V as the aforementioned reigning monarch of the time, and going back through history to the legendary Richard I or Richard the Lionheart of the 12th Century, which was applied to unit 6027, while later class members 6028 and 6029, which adopted the names King Henry II, the first Plantagenet King who ascended to the throne in 1154, and King Stephen, grandson of William the Conqueror who took the crown during a succession crisis and later civil war known as the Anarchy against his cousin, the Empress Matilda, were later renamed in the 1930s to King Edward VIII, who infamously abdicated prior to his coronation due to his notorious romance with American divorcee Wallace Simpson, and King George VI, his younger brother who succeeded him and led Britain through World War II.
Throughout the remainder of the 1920s, the King Class proved to be an incredibly successful range of locomotives that provided performance and power that was unmatched by any other 4-6-0 configuration engine in the UK, convincing the Great Western management to order a second batch of ten locomotives from Swindon between May and August 1930, although on January 15th, 1936, number 6007, King William III, hauling the 9pm Penzance to Paddington express, collided with a stationary brake van and five wagons at the rear of a special mineral train from Aberdare to Old Oak Common at Shivenham in Oxfordshire due to a broken drawhook which went unnoticed by the crew of the goods train, the King class striking the consist at around 60mph and causing a major derailment that saw the engine left upturned on the opposite track, although in the ensuing carnage, only the driver and one of the passengers were killed, while 27 others were wounded, the accident writing off 6007, and thus requiring its replacement with a new engine that repurposed the boiler from its destroyed predecessor, the rebuilt engine receiving the same number and name.
In 1935, amid a growing trend for art-deco streamlining as per contemporary cars and aircraft designs, Collett, as a gesture made to appease the public relations department of the Great Western, applied a very basic streamlined casing to engine 6014 ‘King Henry VII’ so as to ensure that the GWR had their own streamlined locomotive present by the time the LNER launched its highly anticipated Gresley A4 Pacific locomotives which featured the famous Bugatti nose, this appendage consisting of a rounded nose cone and hastily added air-smoothed casings onto the locomotive’s leading edges so as to give the most basic improvements in aerodynamics, this purely aesthetic exercise eventually being removed during 1937, although the wedge-shaped front to the cab was retained until 1953.
Through World War II and into the nationalised era of British Railways, the Kings remained the frontline express passenger locomotive for the trunk routes of the newly formed Western Region, although even amid drives to pursue electric and diesel technology as the future for UK rail traction, experiments in 1947 were undertaken in order to fit a four-row high-degree superheater in Number 6022, King Edward III, owing to a decline in the availability of high-calorific South Wales steam coal on which the Great Western had always relied for its good locomotive performance, the lack of this vital fuel being demonstrated during the 1948 locomotive exchanges, when 6018 King Henry VI, transferred to the former LNER mainline of the North Eastern region, had performed disappointingly due to its use of locally sourced Yorkshire coal, despite demonstrating the 4-6-0 type’s unique sure-footedness when climbing out of Kings Cross while equivalent ex-LNER Pacifics often slipped during their departure, the outcome of the superheater experiments resulting in these units being fitted to all members of the class, and modifications were also made to the draughting arrangement.
From September 1955, double blast-pipes and chimneys were also fitted, initially on 6015 King Richard III, and later for the rest of the class throughout the remainder of the year, the fitting of double-chimneys resulting in these locomotives performing at their absolute best when under the auspices of British Railways, and were now able to climb the notorious South Devon banks of Dainton, Rattery, and Hemerdon unassisted, with workings of the Cornish Riviera Express being recorded at speeds of up to 108mph when under the haulage of King class locomotives, thereby making them the fastest authenticated speed achieved on the former Great Western Railway network, but not the fastest post-war speed record for steam overall, as this was attained by LNER A4 pacific number 60007 Sir Nigel Gresley following a record breaking run in 1959 when it achieved 112mph.
By 1960, the King class were allocated to five depots across the former Great Western network, Old Oak Common in West London, Laira in Plymouth, Cardiff Canton, Bristol Bath Road and Stafford Road near Wolverhampton Low Level, although it wasn’t unknown for Kings to be briefly allocated to other sheds, such as the expansive facility at Newton Abbott during 1948 and 1949, the thirty members of the fleet essentially maintaining their top-line express operations until the arrival of diesel replacements during 1958 with the Class 42 and 43 Warship diesel-hydraulics, although due to severe reliability problems, especially among the North British-built Class 43s, the Kings were often found either deputising or rescuing their diesel successors on a regular basis, and thereby prolonged their imminent withdrawal by at least two years against their original proposed retirement of 1960.
The final nail in the coffin for the Kings came in 1961 with the appearance of the Class 52 Westerns, a diesel-hydraulic design that was far superior to that of the preceding Warships, and with the class illustrating a regular 90mph top speed and exceptional reliability, the 30 members of the Great Western’s 6000 class were removed from service throughout the course of 1962, the first engine, 6006 King George I, being retired from Stafford Road shed in February of that year, while the last, 6025 King Henry III, was withdrawn from Old Oak Common in December, the Kings, unlike many other ex-Great Western classes, having a much lower survivability rate as a majority of these engines were broken up at either their birthplace of the Swindon Works, Cashmore’s in Newport, or Cox & Danks in Oldbury, rather than being sent to the Barry Scrapyard of South Wales where a vast array of withdrawn steam locomotives would end up being preserved.
In the end, only three members of this distinctive class were saved from the cutter’s torch, class premier, 6000 King George V, which is on static display within the former Swindon Works at the Museum of the Great Western, 6023 King Edward II, which wears a unique dark blue livery and is owned by the Didcot Railway Centre, where it is currently awaiting an overhaul, and 6024 King Edward I, which was until 2012 a regular performer on the mainline and conveyed a variety of railtours across the network, but is now currently undergoing a 10-year overhaul at the West Somerset Railway so as to return it to mainline operation, though due to the restricted height clearances now presented by the arrival of overhead electric wires, preserved Kings intended for the mainline have seen their cab and chimneys, as well as some of the upper pipework, reduced vertically by 4 inches so as to fit within the UK loading gauge, the only example to retain its original appearance, as withdrawn, being King George V.
In the end, the King Class of the Great Western proved to be among the most formidable steam locomotive designs ever to run on the British railway network, as despite these mighty machines not having the same streamlined art-deco looks of other premier flagship passenger engine classes of the time, their utilitarian and purposeful nature was a testament to their strength when hauling some of the most famous express trains in the UK, and today hold a strong place in the heart of enthusiasts for its many superb achievements.