The blade and ripper of the bulldozer can't really do anything much if it can't move in the first place, and the way that it moves is largely due to what some people would call dozer rails.
Dozer rails, also known as continuous or caterpillar tracks, are plates or pads that are linked and pivoted together to form a sort of endless chain wrapped around a series of wheels on a bulldozer. Bulldozers, machines that are formally known as track-type or track-laying tractors, have one dozer rail on each side. The term "dozer rail" for a continuous track is a term of affection that may have stemmed from "bulldozer" and the "endless railway wheel."
History of the Dozer Rail
There are claims by experimental archaeologists that Egyptians used logs held together with belts during the construction of the pyramids. The modern-day continuous track, however, is attributed to the English inventor Richard Lovell Edgeworth, who came up with the idea in 1770. There were other inventors who had patented their own versions of the continuous track, such as Sir George Cayley in 1826 ("universal railway"), Dmitry Zagryazhsky in 1839, and James Boydell ("endless railway wheel") in 1853. The first commercially successful implementation of the continuous track, however, was in a 1901 steam log hauler developed by an American named Alvin Lombard. Since then, continuous tracks have been used in steam rollers, steam engines, military tanks, and tractors, such as the first bulldozer designed by James Cummings in the 1920s.
The Advantage of Dozer Rails Over Wheels
The key to the function of continuous tracks or dozer rails is weight distribution. Wheels on heavy machinery like tractors tend to move sluggishly or even get trapped in soft surfaces like soil. Obtaining maximum traction was very difficult without dozer rails, as the weight of the machine tends to be focused on the small surface area of the wheels. Dozer rails solve the problem by distributing the weight of the tractor and increasing the surface area of the moving parts that comes in contact with the ground. The wide dozer rails keep the tractor from sinking as well as help maneuver better in softer soil.
Dozer Rail Applications
Dozer rails find obvious applications in the tractors that named them, bulldozers. Other than bulldozers, dozer rails are used on any vehicle that requires maneuverability on soft ground, such as backhoe loaders, tanks, mining trucks, gas turbines and farm tractors.