GWR Thunderer locomotive
|Designer||T. E. Harrison|
|Builder||R. & W. Hawthorn & Co.|
|Gauge||7 ft (2,134 mm)|
|Driver diameter||6 ft 0 in (1,829 mm)|
|Wheelbase||7 ft 0 in (2.13 m)|
|Cylinder size||16 in × 20 in (406 mm × 508 mm)|
|Operator(s)||Great Western Railway|
|Number in class||1|
Thunderer was the first of a pair of locomotives (the other being Hurricane) built for the Great Western Railway (GWR), England, by R. & W. Hawthorn & Co. whose design was very different from other steam locomotives. In order to meet Isambard Kingdom Brunel's strict specifications, an 0-4-0 frame carried the 'engine', while the boiler was on a separate six-wheeled frame. The driving wheels were geared 10:27 in order to reduce the cylinder stroke speed while allowing high track speed, in line with the specifications.
The locomotive was delivered to the GWR on 6 March 1838 and ceased work in December 1839 after running only 9,882 miles, but its boiler section was kept as a stationary boiler.
- GWR Hurricane locomotive - the second Hawthorn locomotive
- GWR Haigh Foundry locomotives - further geared locomotives
- Reed 1953, p. B11
- Reed, P.J.T. (February 1953). White, D.E., ed. The Locomotives of the Great Western Railway, Part 2: Broad Gauge. Kenilworth: Railway Correspondence and Travel Society. ISBN 0-901115-32-0.
- Waters, Laurence (1999). The Great Western Broad Gauge. Hersham: Ian Allan Publishing. ISBN 0-7110-2634-3.