Christopher Blackett (1751-1829) appointed William Hedley to the job of viewer at Wylam Colliery in 1805, a position he had held at Walbottle. Hedley remained in this post for twenty years. With Timothy Hackworth (q.v.) and Jonathan Forster as executants, Hedley conducted experiments to demonstrate the adhesion qualities of the smooth railway wheel. This led on to his work of 1813-15 using direct, rather than rack adhesion. Two of his experimental locomotives survive, Puffing Billy, now in the Science Museum in London, and Wylam Dilly in the Royal Scottish Museum, Edinburgh.
While still viewer at Wylam, Hedley acquired interests in shipping, and other collieries and in c 1828, after leasing Callerton colliery, north of Throckley, he and his family moved from Wylam. Thereafter, Hedley concentrated on his coal interests, but he was always conscious of his status as a pioneer and when Dr Dionysius Lardner, in a lecture at Newcastle, described George Stephenson as the 'father of the locomotive', Hedley inserted a notice in the local press for three weeks asserting his priority.
Hedley lived at Burnhopeside Hall, Lanchester, where there is a memorial tablet in the church, though he is actually buried at Newburn. There is also a memorial plaque on Rose Cottage, Wylam.