| Power Classification | |
| Introduced | 1845 |
| Designer | Timothy Hackworth. |
| Company | Stockton & Darlington Railway |
| Weight | 22t |
| Driving Wheels | 4ft 0in |
| Boiler Pressure | 75lbf |
| Cylinders | 14½in x 24in |
| Tractive Effort | 6,700lbf |
| Valve Gear | Gab |
Derwent was built by W&A Kitching, of Darlington in 1845 at a cost of £1,140, to the design of Timothy Hackworth, for the Stockton & Darlington Railway. It was one of several engines of a class which were all produced by 1848.
Locomotive development on the Stockton & Darlington Railway under Timothy Hackworth was distinctly idiosyncratic and seemingly oblivious to the development so close by of the classic Stephensonian locomotive, ie with multi-tube boiler and front-located cylinders, and evolved as such as early as 1830. Quite remarkably S&DR 0-6-0 25 Derwent was built as late as 1845 (at the same time as GJR 2-2-2 Columbine and FR 0-4-0 No.3), combining a single return flue boiler, which of necessity was fired from the smokebox end, with its cylinders at the rear. Furthermore, there were no main frames as such, the axles were effectively individually secured to the boiler, and the wheels were of the two-part cast iron plug type, as actually pioneered on Locomotion 20 years earlier. Some engines of this general type (but not 25) were later rebuilt with multitubular boilers and were referred to as ‘firebox’ engines.
 | Derwent built by Hackworth in 1845 |
 | Columbine introduced on the Grand Junction Railway in 1845 |
 | Coppernob Number 3 introduced in 1846 on the Furness Railway |
It was purchased in 1868 by Messrs Peace & Partners of Darlington for use on Pease-owned West Collieries lines near Crook. In 1898 they presented the engine to the North Eastern Railway for preservation.
It was placed on a plinth at Darlington Bank Top station Darlinton Bank Top station, where it remained, except for more secure storage during the Second World War, until 1961 when it was refurbished at Darlington Works.
It participated in the Stockton & Darlington Railway centenary celebrations in 1925.
The shell of another very similar engine (Bradyll) which was built ten years before Derwent was withdrawn from service in 1875 and improvised as a snow plough at Hetton Colliery. It remained in this form until the late 1940s and is now preserved in this condition.
Derwent is now on display at the Darlington Railway Centre and Museum, located in the same building as Darlington’s North Road station. It is on long-term loan from the National Railway Museum as it forms part of the National Collection.
| Home Base | Current Status | Owner |
| Head of Steam Museum, Darlington | On static display | National Railway Museum NRM Object Number{1978-7012} |
Preserved British Steam Locomotives 