Complex sentence: The "Kansas City Mule" and "St. Louis Mule" were a pair of 283-mile (455 km) passenger trains operated by Amtrak running between St. Louis and Kansas City, Missouri as part of the "Missouri Service" train network.
Split into simpler sentences: The "Kansas City Mule" and "St. Louis Mule" are a pair of 283-mile (455 km) passenger trains operated by Amtrak running between St. Louis and Kansas City, Missouri. They operate as part of the "Missouri Service" train network.