LNWR 3020 Cornwall Class

LNWR No. 3020 Cornwall is one of the most celebrated locomotives in British railway history: a 4-2-2 single-driver express locomotive originally built at Crewe Works in 1847 to the design of Francis Trevithick with an extraordinarily unusual configuration — the boiler was positioned below the driving axle rather than above it, giving the locomotive an eccentric and impractical layout that was quickly modified. Despite its troubled origins, Cornwall was rebuilt in 1858 by John Ramsbottom into a more conventional 4-2-2 single-driver express locomotive, and in this rebuilt form it enjoyed a long and successful career as one of the LNWR's express engines before being preserved in 1927.

The original 1847 Cornwall was designed by Francis Trevithick — son of the pioneering steam engineer Richard Trevithick — and represented an attempt to achieve the lowest possible centre of gravity by placing the boiler beneath the 8 ft 6 in driving wheel. The driving wheel was enormous by any standard, larger even than the GWR's broad-gauge single-drivers, but the boiler-below-axle arrangement proved impractical in service and the locomotive was rebuilt in 1858 with a conventional boiler above the axle, a smaller 8 ft 6 in driving wheel, and the familiar elegant single-driver express profile.

In its rebuilt form Cornwall worked LNWR express services for many years, and the locomotive's extraordinary 8 ft 6 in driving wheel made it the largest-wheeled locomotive ever to work in regular service in Britain. It was preserved by the LNWR in 1927 and is now displayed at the National Railway Museum, York, where it represents both the Victorian single-driver express tradition and the extraordinary engineering ambition of the early railway age.