Complex sentence: The railroad, which extended into the area in 1883, served as a catalyst to the cattle industry but later contributed to its decline by bringing farmers and sheep men to the area, thus creating increased competition for productive land.
Split into simpler sentences: The railroad, which extended into the area in 1883, served as a catalyst to the cattle industry but later contributed to its decline. By bringing farmers and sheep men to the area, it created increased competition for productive land.