Complex sentence: Although its primary purpose today is as a rail route for coal and freight and as a water tunnel from the Pacific watershed to Colorado's Front Range population centers, tourists and cross-country passengers can enjoy the route on Amtrak's California Zephyr.
Split into simpler sentences: Although its primary purpose today is as a rail route for coal and freight and as a water tunnel from the Pacific watershed to Colorado's Front Range population centers. Tourists and cross-country passengers can enjoy the route on Amtrak's California Zephyr.