In 1812 William Hedley, was commissioned by Christopher Blackett, the owner of Wylam Colliery, to produce a steam locomotive. Hedley was helped in his task by two talented craftsman, Jonathan Forster, an enginewright, and Timothy Hackworth, a blacksmith. By 1814 Hedley produced a locomotive that had two vertical cylinders outside the boiler. Piston rods extended upwards to pivotted beams, which were in turn connected by rods to a crankshaft beneath the frames, from which gears drove and also coupled the wheels. Originally carried on four wheels, the 8 ton locomotives were two heavy for the plate rails, and so to spread the weight on the templates, they were redesigned with eight wheels. Two of these locomotives were still working at Wylam Colliery in 1860. This included Puffing Billy and Wylam Dilly.