The California Zephyr is a scenic passenger train route operated by Amtrak that travels between Chicago and San Francisco. It covers approximately 2,400 miles and showcases stunning landscapes, including the Rocky Mountains and the Sierra Nevada. This train service was first introduced in 1949 and has become known for its panoramic views and comfortable accommodations. The journey typically takes about 51 hours, making it a popular choice for travelers seeking a leisurely experience through some of the most beautiful regions in the United States.