Engineer to the Great Western Railway

• Isambard Kingdom Brunel (1833-1837)

Locomotive Superintendent

• Daniel Gooch (1837–1864)
• Joseph Armstrong (1864–1877)
• William Dean (1877–1902)
• George Jackson Churchward (1902–1915)

Chief Mechanical Engineer

• George Jackson Churchward (1915–1921)
• Charles Collett (1922–1941)
• Frederick Hawksworth (1941–1947)

Northern Division Locomotive Superintendent

• Joseph Armstrong (1854–1864)
• George Armstrong (1864–1892)

Mechanical and Electrical Engineer

• Kenneth J Cook (1950–1951)
• Robert A Smeddle (1951–?)

Birkenhead Railway

• John Dixon
• T A Yarrow
• Rendell
• William Bragge
• George Douglas (1851–1860)

Bristol and Exeter Railway

• Charles Gregory (1849–1850) (Chief Engineer)
• James Pearson (1850–1875)

Cornwall Minerals Railway

• Miles Constatine

Llanelly Railway

• Joseph Hepburn
• Robert Hepburn

Llynvi and Ogmore Railway

• J Routledge

Monmouthshire Railway

• W Craig (1849–1854)
• R Laybourne (1854–1868)
• H Appleby (1868–1875)

Rhymney Railway

• Thomas Clements (1858–1862)
• Matthew Mordue (1862–1863)
• John Kendall (1863–1869)
• John Canty (1869–1884)
• Richard Jenkins (1884–1906)
• Charles T. Hurry Riches (1906-1922)

Shrewsbury and Birmingham Railway

• William Marlow (1849–1853)
• Edmund Petre
• Joseph Armstrong

Shrewsbury and Chester Railway

• A M Ross (Engineer)
• Thomas Truss (Carriage Superintendent)
• Edward Jeffreys
• Joseph Armstrong (1853–1854)

South Devon Railway;

• Frederick Gooch (1850–1864)
• Joseph Wright (1864–1876)

Taff Vale Railway

• B. S. Fisher (1869–1873)
• Tom Hurry Riches (1873-1911)
• John Cameron (1911–1922)

Vale of Neath Railway

• Joshua Williams (1851–1865) (General Manager)

West Cornwall Railway

• Skater
• H Appleby
• Joseph Wright (South Devon Railway Locomotive Superintendent)

West Midland Railway

• Edward Wilson (1860–1863)

Newport, Abergavenny and Hereford Railway

• Mark Carr (1854–1858)
• Alexander McDonnell (1858–1860)

Oxford, Worcester and Wolverhampton Railway

• David Joy (1852–1856)
• Frederic Haward (1856–1857)
• Edward Wilson (1857–1860)

• Allen, Cecil J (1948). British Railway Locomotives. Ian Allan.
• MacDermot, E T (1927). History of the Great Western Railway, volume I 1833–1863. London: Great Western Railway.
• MacDermot, E T (1931). History of the Great Western Railway, volume II 1863–1921. London: Great Western Railway.
• The Locomotives of the Great Western Railway, Part 3: Absorbed Engines 1854–1921. The Railway Correspondence and Travel Society. 1956.
• Swindon Steam 1921–1951. Ian Allan. 1974.