GWR Firefly Class
Design and development
When Daniel Gooch was appointed GWR Locomotive Superintendent at the age of 21 in August 1837, he inherited a chaotic locomotive fleet of varying types from different builders, of which only the Star class proved fully reliable. Gooch's response was to draw up a complete set of standard drawings for a new express locomotive — every dimension, every component fully specified — and to place orders with seven different builders to produce engines exactly to those drawings. This was the first time any railway had specified locomotives this precisely; until then, builders had typically been given a general specification and left to design the details.
The Firefly was a conventional Patentee-type 2-2-2 enlarged for the broad gauge, with 7 ft 0 in driving wheels (later increased to 7 ft 6 in as the design developed). 62 were built between March 1840 and December 1842 by Jones Turner & Evans, Sharp Roberts & Co., Hick & Sons, Fenton Murray & Jackson, Mather Dixon & Co., Nasmyth Gaskell & Co., and Stothert & Slaughter — every major British locomotive builder of the period.
Service and withdrawals
The Fireflies entered service progressively from 1840 and rapidly became the GWR's standard express engine. Firefly itself hauled the legendary 1 May 1844 demonstration run from Paddington to Exeter — 194 miles non-stop in 4 hours 40 minutes including stops, an average of 41 mph and a record that stood for many years.
The class was progressively rebuilt by Gooch in the 1860s with new, larger boilers; a number lasted in this rebuilt form until withdrawal of the broad gauge in May 1892. None of the originals survived, but a working full-size replica of Firefly was completed by the Firefly Trust at the Didcot Railway Centre in 2005 and operates regularly there.
Identification features
Broad-gauge 2-2-2 with 7 ft 0 in (later 7 ft 6 in) driving wheels, inside cylinders, copper-capped chimney, and the distinctive Gooch features that became the GWR house style: domeless boiler, polished brass safety-valve cover, and dark green livery. The Didcot replica preserves all the original visual character.
Notable locomotives
- Firefly (1840, original — not preserved)
- Firefly replica (2005, Didcot Railway Centre — operational)