Holt's Continous Linked Track Steam Tractor, or "caterpiller" became an icon of the turn of the century; the first really usable tracked vehicle was in demand for road building, farming, and moving heavy artillery, and could be found working heavy hauling jobs on rough ground into the 1920s,and even the 30s in out of the way places.  the Holt running  gear was the basis of "little willie" churchill's early prototype tank, and the evolutionary stem ancestor of the Tank Mk I, the Whippit, and the French Renault T-18 machines.