The transcontinental railroad because it transcends through the cities.
The First Transcontinental Railroad, also called the Great Transcontinental Railroad and Central Union Pacific Railroad line, was a 1,912-mile (3,077 km) continuous railroad line constructed between 1863 and 1869 that connected the existing eastern U.S. rail network at Omaha, Nebraska/Council Bluffs, Iowa with the Pacific coast at the Oakland Long Wharf on San Francisco Bay, California. the train cuts down travel time from six long months to a week. It was the shortest, quickest and cheapest route south.
Before the completion of the Transcontinental Railroad, it was so expensive to travel across the country, it cost almost $1000 to travel at that time, however, after the railroad was completed, the price dropped to $150 dollars.