Complex sentence: The Radio tractor was a mobile Signal Corps Radio used by the U.S. Army before and during World War I, for ground communications, prior to WWI trucks were referred to as tractors, and there were also telegraph tractors, and telephone tractors.
Split into simpler sentences: The Radio tractor was a mobile Signal Corps Radio used by the U.S. Army before and during World War I, for ground communications. Prior to WWI trucks were referred to as tractors, and there were also telegraph tractors, and telephone tractors.