Interesting!
I do hope it still exists, and has not been thrown away by some later owner or inheritor who did not know its significance.
Although Matlock Tramways’ “fitter” failed to make it run, the article hints it did originally. Or if not, perhaps George Stephenson learnt from it enough to build the Killingworth Colliery locomotive successfully.
Plain wheel rims and an originally fixed forecarriage suggest it was intended for a railway, of flanged plateway form; and I am curious why it was “converted” at some point to a sort of traction-engine, albeit without steering-gear. Possibly the owner of the time wanted it to travel in circles so it could be run to its maximum range in a comparatively restricted area.
Tracing it now would not be easy. The article does not tell us if Mr. Smith belonged to any model-engineering society still extant and able to give more details about him; or might even know what happened to the model later. An brief, illustrated article in something like a local community magazine might yield something. If the engine was sold on it could be anywhere now.