Jonathan Forster

Jonathan Forster was the resident enginewright at the Wylam Colliery in Northumberland during the 1810s and 1820s, one of the small team of practical engineers who built the Wylam locomotives under the direction of the colliery's viewer William Hedley — including the celebrated Puffing Billy and Wylam Dilly, which are the oldest surviving steam locomotives in the world.

Forster's role was that of the skilled practical fabricator: the man who could translate Hedley's engineering concepts and empirical findings into working machinery using the tools and materials available at a working colliery. The development of the Wylam locomotives in 1813–1814 involved a process of practical experiment — testing the hypothesis that smooth-wheeled locomotives could achieve traction on smooth rails without rack mechanisms — in which Forster's hands-on engineering skill was as important as Hedley's theoretical direction. The colliery blacksmith Timothy Hackworth, who would later become a celebrated locomotive engineer in his own right, also worked on the Wylam engines.

Puffing Billy, built in 1813–14, survives at the Science Museum in London as the world's oldest intact steam locomotive, while Wylam Dilly is preserved at the National Museum of Scotland in Edinburgh. Forster's name appears in the Wylam Colliery accounts and in contemporary witness accounts of the locomotives' construction, but few personal biographical details have survived — an unfortunately common fate for the practical engineers whose hands actually built the pioneering machines of the early railway era.