Even though the United States has struggled to build and use passenger rail between major cities, the CEO of Amtrak suggests that shift in where Americans live means there are new opportunities:

There’s 100 million more people in the United States today than there were when Amtrak was created in 1971. And if you look about the shift of where people moved to and where they have moved from, there are 20, 25 dense corridors across our nation where Amtrak has little to no service. And that’s where people have moved to. Think about the corridors in Arizona, between Phoenix and Tucson and Flagstaff, and the route between Las Vegas and Southern California. Look at the growth that we’ve experienced in the Carolinas, for example, from Raleigh to Charlotte and Greensboro and Winston-Salem—we started the service there a couple of years ago with two trains a day, and we’re looking to grow that to six trains a day along that route.

A lot of the growth I’m talking about here would occur on corridors we already serve, but we’re only serving them once a day. Another that comes to mind is Nashville to Atlanta, with stops in Chattanooga. Try to fly that. There’s no service there. It’s a major corridor. It’s an integrated economy. I could go on and on, but I believe these areas of opportunity allow us, over the next 20-year period of time, to double our ridership.

The logic sounds similar to what has been proposed for the Midwest and other corridors in the United States: look to provide good quality passenger train service between cities where the distance means that flying is not that convenient. But, the geography in the example above has shifted from the Midwest, Northeast, or California corridors to the growing Sun Belt where there are plenty of highways but not as many other transit options.

Thinking more about these Sun Belt corridors, it seems like the Amtrak service is waiting for a critical mass of potential riders as opposed to thinking ahead of the population growth. Take the Nashville to Atlanta corridor. These areas have been growing for several decades: the city of Nashville boomed first in the 1960s and then has expanded from nearly 450,000 residents in 1970 to over 670,000 residents in 2019 while the Atlanta metropolitan region grew from just under a million residents in 1950 to over 6 million in 2019. Is it too late for Amtrak to get started with a thriving service or do they demand from potential riders to even consider boosting the amount of service? Imagine if Amtrak had planned for all of this five decades ago and connected the Sun Belt with numerous routes; how might this have affected population growth and transportation patterns? Could the United States have had a sprawling postwar era full of railroad passenger lines?