<div class="htmlview paragraph">Although the crawler tractor has not changed much in appearance in the past 40 years, there have been many internal changes and refinements. It has changed from a machine used to pull something to a machine used to carry tools such as dozers, rippers, shovels, sidebooms, etc. This paper discusses the historical development of the tractor, touching upon some of the design problems. Improvements in present-day machinery, such as bearing life and face seals, are touched upon.</div> <div class="htmlview paragraph">In the future, changes in size, power source, transmissions, suspension systems, and speed can be expected.</div>