A scale, silver model of a tower-pattern steam excavator, with a cantilever-supported brass shovel and chain-controlled height adjustment; on rails. On a stepped wooden base with white metal plaques attached. With fitted wooden case with blue lining.

Steam excavators such as this were known as 'steam navvies' after the workers they replaced. The firm of Ruston, Proctor & Co., of Lincoln, were one of the first engineering firms to create steam-powered excavating machinery of this type. In 1889 the journal The Engineer commented that the company had ‘perhaps done more in locomotive work than any other firm in what is known as the agricultural engineering trade’. This is a model of the type used when on 15 March 1902, George, Prince of Wales (later King George V) dug the first sod of the Royal Edward Dock, Avonmouth.