Harold Holcroft
Encyclopedia
Harold Holcroft was a British
railway and mechanical engineer who worked for the Great Western Railway
(GWR), the South Eastern and Chatham Railway
(SECR) and the Southern Railway (SR). Whilst at the GWR, Holcroft helped the Chief Mechanical Engineer
(CME), George Jackson Churchward
design the 4300 class
2-6-0
moguls, and took the design principles for this class of locomotive with him when he transferred over to the SECR. Here, he worked as Assistant to Richard Maunsell
and was involved with the design of the Maunsell moguls, transferring over to the Southern Railway when the SECR was absorbed at grouping in 1923
. With Maunsell's retirement in 1937, Holcroft continued to work for the Southern Railway under Oliver Bulleid
until his retirement in 1946.
in 1882 and undertook a premium apprenticeship at the Wolverhampton works of the GWR (managed by his uncle E.E. Lucy). He worked in the assembly shop and the drawing office to get an all round feel for railway life, giving him the experience to generate his own ideas. His first patent was filed at the age of 18, which brought Holcroft to the attention of Churchward, enabled him to transfer to Swindon works when his apprenticeship was completed. As one of Churchward's rising prodigies in the heyday of GWR locomotive development, Holcroft helped with the design of several of Churchward's locomotives, notably the 4300 class 2-6-0.
Whilst with the GWR, he collaborated with Sir Nigel Gresley to invent and patent the Gresley conjugated valve gear
for 3-cylinder locomotives. Holcroft continued to develop this mechanism by driving the "middle" cylinder of a steam locomotive from the combination levers of an "outside" cylinder, as opposed to Gresley's method of using direct transmission from the valve spindle. Holcroft's method had a number of advantages. The Gresley design of conjugated valve gear suffered from variations in valve events brought about by heat expansion of the valve spindles and flexing of the conjugation levers, affecting the valve events when the locomotive was under way. By using the combination lever assembly to drive the "middle" cylinder, Holcroft managed to circumvent these problems.
.
, Surrey
on 15 February 1973. Holcroft wrote a book, Locomotive Adventure about his experiences regarding the development of steam locomotives in Britain. He was also editor of Railway Engineering Abstracts (some of these abstracts were used for the later material in Steam Locomotive Development). A collection of Holcroft's papers are archived at the National Railway Museum
, and include the manuscript for a second autobiography entitled Life with Locos.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
railway and mechanical engineer who worked for the Great Western Railway
Great Western Railway
The Great Western Railway was a British railway company that linked London with the south-west and west of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament in 1835 and ran its first trains in 1838...
(GWR), the South Eastern and Chatham Railway
South Eastern and Chatham Railway
The South Eastern and Chatham Railway Companies Joint Management Committee , known by its shorter name of the South Eastern and Chatham Railway was a working union of two neighbouring rival railways, the South Eastern Railway and London, Chatham and Dover Railway , that operated services between...
(SECR) and the Southern Railway (SR). Whilst at the GWR, Holcroft helped the Chief Mechanical Engineer
Chief Mechanical Engineer
Chief Mechanical Engineer and Locomotive Superintendent are titles applied by British, Australian, and New Zealand railway companies to the person ultimately responsible to the board of the company for the building and maintaining of the locomotives and rolling stock...
(CME), George Jackson Churchward
George Jackson Churchward
George Jackson Churchward CBE was Chief Mechanical Engineer of the Great Western Railway in the United Kingdom from 1902 to 1922.-Early career:...
design the 4300 class
GWR 4300 Class
The Great Western Railway 4300 Class is a class of 2-6-0 steam locomotive.- Overview :The class was introduced in 1911 to a G.J. Churchward design. 342 were built until 1932...
2-6-0
2-6-0
Under the Whyte notation for the classification of steam locomotives, 2-6-0 represents the wheel arrangement of two leading wheels on one axle, usually in a leading truck, six powered and coupled driving wheels on three axles, and no trailing wheels. This arrangement is commonly called a Mogul...
moguls, and took the design principles for this class of locomotive with him when he transferred over to the SECR. Here, he worked as Assistant to Richard Maunsell
Richard Maunsell
Richard Edward Lloyd Maunsell held the post of Chief Mechanical Engineer of the South Eastern and Chatham Railway from 1913 until the 1923 Grouping and then the post of CME of the Southern Railway in England until 1937....
and was involved with the design of the Maunsell moguls, transferring over to the Southern Railway when the SECR was absorbed at grouping in 1923
Railways Act 1921
The Railways Act 1921, also known as the Grouping Act, was an enactment by the British government of David Lloyd George intended to stem the losses being made by many of the country's 120 railway companies, move the railways away from internal competition, and to retain some of the benefits which...
. With Maunsell's retirement in 1937, Holcroft continued to work for the Southern Railway under Oliver Bulleid
Oliver Bulleid
Oliver Vaughan Snell Bulleid was a British railway and mechanical engineer best known as the Chief Mechanical Engineer of the Southern Railway between 1937 and the 1948 nationalisation, developing many well-known locomotives.- Early life and Great Northern Railway :He was born in Invercargill,...
until his retirement in 1946.
Early life, GWR service and Holcroft conjugated valve gear
Holcroft was born at WolverhamptonWolverhampton
Wolverhampton is a city and metropolitan borough in the West Midlands, England. For Eurostat purposes Walsall and Wolverhampton is a NUTS 3 region and is one of five boroughs or unitary districts that comprise the "West Midlands" NUTS 2 region...
in 1882 and undertook a premium apprenticeship at the Wolverhampton works of the GWR (managed by his uncle E.E. Lucy). He worked in the assembly shop and the drawing office to get an all round feel for railway life, giving him the experience to generate his own ideas. His first patent was filed at the age of 18, which brought Holcroft to the attention of Churchward, enabled him to transfer to Swindon works when his apprenticeship was completed. As one of Churchward's rising prodigies in the heyday of GWR locomotive development, Holcroft helped with the design of several of Churchward's locomotives, notably the 4300 class 2-6-0.
Whilst with the GWR, he collaborated with Sir Nigel Gresley to invent and patent the Gresley conjugated valve gear
Gresley conjugated valve gear
The Gresley conjugated valve gear is a valve gear for steam locomotives designed by Sir Nigel Gresley, chief mechanical engineer of the LNER, assisted by Harold Holcroft...
for 3-cylinder locomotives. Holcroft continued to develop this mechanism by driving the "middle" cylinder of a steam locomotive from the combination levers of an "outside" cylinder, as opposed to Gresley's method of using direct transmission from the valve spindle. Holcroft's method had a number of advantages. The Gresley design of conjugated valve gear suffered from variations in valve events brought about by heat expansion of the valve spindles and flexing of the conjugation levers, affecting the valve events when the locomotive was under way. By using the combination lever assembly to drive the "middle" cylinder, Holcroft managed to circumvent these problems.
Service with the SECR and the Southern Railway
When the Churchward development programme of new locomotives began to slow down, Holcroft sought employment with a railway still in need of original design work. He joined Richard Maunsell's design team as an Assistant, participating in the latter's contributions to the SECR and Southern Railway's motive power. Holcroft's idea for conjugated valve gear were incorporated into Maunsell's N1 class, K1 class and U1 class three-cylinder locomotives. He stayed with the Southern Railway after Maunsell's retirement in 1937 to work with Oliver BulleidOliver Bulleid
Oliver Vaughan Snell Bulleid was a British railway and mechanical engineer best known as the Chief Mechanical Engineer of the Southern Railway between 1937 and the 1948 nationalisation, developing many well-known locomotives.- Early life and Great Northern Railway :He was born in Invercargill,...
.
Retirement
Holcroft retired from the Southern Railway in 1946, and worked on periodicals for the Institute of Civil Engineers. He died in TadworthTadworth
Tadworth is a large suburban village in Surrey, on the south-east slope of Epsom Downs. It forms part of the Borough of Reigate and Banstead. The census area Tadworth and Walton has a population of 7,016. Neighbouring settlements include Walton-on-the-Hill, Kingswood, Epsom, Burgh Heath, Banstead,...
, Surrey
Surrey
Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...
on 15 February 1973. Holcroft wrote a book, Locomotive Adventure about his experiences regarding the development of steam locomotives in Britain. He was also editor of Railway Engineering Abstracts (some of these abstracts were used for the later material in Steam Locomotive Development). A collection of Holcroft's papers are archived at the National Railway Museum
National Railway Museum
The National Railway Museum is a museum in York forming part of the British National Museum of Science and Industry and telling the story of rail transport in Britain and its impact on society. It has won many awards, including the European Museum of the Year Award in 2001...
, and include the manuscript for a second autobiography entitled Life with Locos.
External links
- http://www.steamindex.com/people/holcroft.htm Steam Index biography of Holcroft.