Complex sentence: The "California Zephyr" is a passenger train route operated by Amtrak from Chicago, Illinois, in the east to Emeryville, California, in the west, passing through the states of Illinois, Iowa, Nebraska, Colorado, Utah, Nevada, and California.
Split into simpler sentences: The "California Zephyr" is a long passenger train route operated by Amtrak in the midwestern and western United States. It runs from Chicago, Illinois, in the east to Emeryville, California, in the west, passing through the states of Illinois, Iowa, Nebraska, Colorado, Utah, Nevada, and California.