In 1803, when aged 22, George Stephenson was appointed as the Superintendent Engineer at Killingworth Colliery. Stephenson persuaded Sir Thomas Liddle, later Lord Ravensworth, that the colliery would benefit from the use of steam locomotives and in 1814 he was allowed to construct his first locomotive. It had two cylinders 8 inches in diameter with a stroke of 24 inches. The boiler was 34 inches in diameter and 8 feet long with a single fire tube of 20 inches diameter passing through it. This gave less heating surface than a return flue but was cheaper and easier to construct. The cylinders were placed vertically along the centreline of the boiler like Blenkinsop's locomotives. The exhaust steam was released straight to the atmosphere. A full-size, working replica of this locomotive has been constructed and can be seem at Beamish Open Air Museum. The staff using contemporary illustrations, a painting, and the original account book for the building of the engine, produced a set of engineering drawings and, in October 1999, started the task of building The Elephant. Much of the construction was done in the North of England. The locomotive was completed and placed in service on 21st march 2002.