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Charles Collett
Charles Benjamin Collett OBE JP MInstCE MIMechE (10 September 1871 – 5 April 1952) was Chief Mechanical Engineer of the Great Western Railway from 1922 to 1941. He designed (amongst others) the GWR's 4-6-0 Castle and King Class express passenger locomotives.
Collett was educated at the Merchant Taylors' School (then at Charterhouse Square, London) and the City and Guilds College of London University. He then became an engineering pupil at Maudslay, Sons and Field, a firm that built marine steam engines. In 1893 he entered the GWR Drawing Office at Swindon as a junior draughtsman. Four years later he was put in charge of the buildings section, and in 1898 became assistant to the Chief Draughtsman. In June 1900 he was appointed Technical Inspector, and soon after Assistant Manager, at the Swindon Works. In 1912 he rose to be Manager of the Works, then in 1919 he was made Deputy Chief Mechanical Engineer of the GWR.
Collett's predecessor, George Jackson Churchward, had delivered to the GWR from Swindon a series of class-leading and innovative locomotives, and arguably by the early 1920s the Great Western‘s 2-cylinder and 4-cylinder 4-6-0 designs were substantially superior to the locomotives of the other railway groupings.
In 1922 Churchward retired, and Collett inherited a legacy of excellent standardised designs. But, with costs rising and revenues falling, there was a need to rationalise the number of pre-grouping designs and to develop more powerful locomotives. Collett was a practical development engineer and he took Churchward's designs and developed them – notably the Hall from the Saint class, and the Castle from the Star. He was also responsible for more humble locomotives, such as many of the pannier tank classes.
By the time Churchward retired, his 4-cylinder Star class locomotives were becoming inadequate for the increasing loads and speeds expected of express passenger trains. To solve this, Churchward had proposed fitting a No 7 boiler (designed for the 4700 class 2-8-0 express freight engines) onto a Star. This was not possible, because the weight would be too great for the track. Instead, Collett enlarged the Star design, leaving the wheels the same but with bigger cylinders and a new standard boiler that would not exceed the 19+1⁄2 ton permitted axle load. He also fitted a more comfortable cab. The result was christened the Castle class, and the first engine, No 4073 Caerphilly Castle, was soon proudly paraded at the British Empire Exhibition, (placed close to the larger LNER Flying Scotsman) with the claim that it was 'Britain's most powerful passenger locomotive'.
One result of this provocative claim was an agreed exchange of locomotives between the companies. Castle class No 4079 Pendennis Castle went to the LNER in exchange for A1 class No 4474 Victor Wild. Both engines acquitted themselves well, but the performance of the smaller Castle led Gresley to investigate the cause and redesign the A1's valves, as well as give them a higher boiler pressure.
As well as rebuilding several Star class locomotives into Castles, Collett shocked some people by rebuilding the GWR's flagship 4-6-2 locomotive No 111 The Great Bear into a 4-6-0 Castle. This at least drew the attention of General Manager Sir Felix Pole to the restrictive permitted axle loads, which had constrained the usefulness of this prestige symbol. When larger locomotives were needed, Sir Felix instructed the Civil Engineer to ensure that the main lines (Paddington–Plymouth, via Westbury or Bristol, and Paddington–Wolverhampton via Bicester) could carry a 22+1⁄2 ton axle load. This was quickly done, since work was already underway to meet this standard.
By 1926, the other railway companies were catching up with the GWR, with designs such as the LNER Pacifics (improved as a result of the GWR/LNER locomotive exchange), SR Lord Nelson class, and the imminent LMS Royal Scot Class. Better locomotives were needed not only for faster and heavier trains, but also for to uphold the prestige of the GWR. Collett started by testing 6 ft 6 in driving wheels on No 5001 Llandovery Castle. When this proved satisfactory, he spread these wheels out under a larger and higher-pressure boiler, and increased the piston stroke to 28 inches, pushing the design to the limit both of the loading gauge and the newly increased axle load. Fitting these increased dimensions together required an unusual front bogie, with outside bearings on the front axle but inside bearings on the rear, to clear the inside and outside cylinders respectively. Finally, the first loco (or first five) had cylinders bored out to 16+1⁄4 inches. The significance of this small change was that it pushed the calculated tractive effort over 40,000 lbs, as required by Sir Felix Pole, thereby emphasising the locomotive's status as the most powerful passenger locomotive in the country. It was named the King class.
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Charles Collett
Charles Benjamin Collett OBE JP MInstCE MIMechE (10 September 1871 – 5 April 1952) was Chief Mechanical Engineer of the Great Western Railway from 1922 to 1941. He designed (amongst others) the GWR's 4-6-0 Castle and King Class express passenger locomotives.
Collett was educated at the Merchant Taylors' School (then at Charterhouse Square, London) and the City and Guilds College of London University. He then became an engineering pupil at Maudslay, Sons and Field, a firm that built marine steam engines. In 1893 he entered the GWR Drawing Office at Swindon as a junior draughtsman. Four years later he was put in charge of the buildings section, and in 1898 became assistant to the Chief Draughtsman. In June 1900 he was appointed Technical Inspector, and soon after Assistant Manager, at the Swindon Works. In 1912 he rose to be Manager of the Works, then in 1919 he was made Deputy Chief Mechanical Engineer of the GWR.
Collett's predecessor, George Jackson Churchward, had delivered to the GWR from Swindon a series of class-leading and innovative locomotives, and arguably by the early 1920s the Great Western‘s 2-cylinder and 4-cylinder 4-6-0 designs were substantially superior to the locomotives of the other railway groupings.
In 1922 Churchward retired, and Collett inherited a legacy of excellent standardised designs. But, with costs rising and revenues falling, there was a need to rationalise the number of pre-grouping designs and to develop more powerful locomotives. Collett was a practical development engineer and he took Churchward's designs and developed them – notably the Hall from the Saint class, and the Castle from the Star. He was also responsible for more humble locomotives, such as many of the pannier tank classes.
By the time Churchward retired, his 4-cylinder Star class locomotives were becoming inadequate for the increasing loads and speeds expected of express passenger trains. To solve this, Churchward had proposed fitting a No 7 boiler (designed for the 4700 class 2-8-0 express freight engines) onto a Star. This was not possible, because the weight would be too great for the track. Instead, Collett enlarged the Star design, leaving the wheels the same but with bigger cylinders and a new standard boiler that would not exceed the 19+1⁄2 ton permitted axle load. He also fitted a more comfortable cab. The result was christened the Castle class, and the first engine, No 4073 Caerphilly Castle, was soon proudly paraded at the British Empire Exhibition, (placed close to the larger LNER Flying Scotsman) with the claim that it was 'Britain's most powerful passenger locomotive'.
One result of this provocative claim was an agreed exchange of locomotives between the companies. Castle class No 4079 Pendennis Castle went to the LNER in exchange for A1 class No 4474 Victor Wild. Both engines acquitted themselves well, but the performance of the smaller Castle led Gresley to investigate the cause and redesign the A1's valves, as well as give them a higher boiler pressure.
As well as rebuilding several Star class locomotives into Castles, Collett shocked some people by rebuilding the GWR's flagship 4-6-2 locomotive No 111 The Great Bear into a 4-6-0 Castle. This at least drew the attention of General Manager Sir Felix Pole to the restrictive permitted axle loads, which had constrained the usefulness of this prestige symbol. When larger locomotives were needed, Sir Felix instructed the Civil Engineer to ensure that the main lines (Paddington–Plymouth, via Westbury or Bristol, and Paddington–Wolverhampton via Bicester) could carry a 22+1⁄2 ton axle load. This was quickly done, since work was already underway to meet this standard.
By 1926, the other railway companies were catching up with the GWR, with designs such as the LNER Pacifics (improved as a result of the GWR/LNER locomotive exchange), SR Lord Nelson class, and the imminent LMS Royal Scot Class. Better locomotives were needed not only for faster and heavier trains, but also for to uphold the prestige of the GWR. Collett started by testing 6 ft 6 in driving wheels on No 5001 Llandovery Castle. When this proved satisfactory, he spread these wheels out under a larger and higher-pressure boiler, and increased the piston stroke to 28 inches, pushing the design to the limit both of the loading gauge and the newly increased axle load. Fitting these increased dimensions together required an unusual front bogie, with outside bearings on the front axle but inside bearings on the rear, to clear the inside and outside cylinders respectively. Finally, the first loco (or first five) had cylinders bored out to 16+1⁄4 inches. The significance of this small change was that it pushed the calculated tractive effort over 40,000 lbs, as required by Sir Felix Pole, thereby emphasising the locomotive's status as the most powerful passenger locomotive in the country. It was named the King class.