c. 1879 The Darby steam-digger
“Image with consent of the descendants of Robert Hasler.
“The Darby Steam-Digger, a light traction engine, was invented circa 1879 by farmer Thomas Darby and built at Lodge Farm Pleshey, near Chelmsford in Essex, England. Robert Hasler, seen driving the Digger, helped to build this first prototype.
“In effect the machine was an early tractor designed mainly for ploughing, and could accomplish 1-acre (4,000 m2) an hour (1 m²/s) to a maximum depth of 14 inches (360 mm). This first digger was constructed on pedestrian principles and had six “feet” and really did walk over the fields. Unfortunately it jumped too much to be really successful. The digger was later modified to have wheels in place of the legs.”
Michael Bradley - Time Traveler 