Its excessive weight cracked the iron rails, rendering it impractical, and steam locomotives were not adopted at the time.

[6][7] During this time Christopher Blackett, owner of the Wylam Colliery, took advantage of the pit's idleness to experiment with the idea of a locomotive-hauled tramway worked purely by adhesion, rather than the Blenkinsop rack system that would be used on the Middleton.

[11] In the September 1814 edition of Annals of Philosophy two locomotives with rack wheels are mentioned (probably Salamanca and Blücher), then there is mention of "another steam locomotive at Newcastle, employed for a similar purpose [hauling coals], and moving along without any rack wheel, simply by its friction against the rail road".

Puffing Billy incorporated a number of novel features, patented by Hedley, which were to prove important to the development of locomotives.

Running on cast-iron wagonway plates, its eight-ton weight was too heavy and broke them, encouraging opponents of locomotive traction to criticise the innovation.

Puffing Billy was an important influence on George Stephenson, who lived locally, and its success was a key factor in promoting the use of steam locomotives by other collieries in north-eastern England.

It has been suggested that Puffing Billy's name survives in the English language in the intensifier like billy-o, but there are several alternative explanations for that phrase's origin.