The east coast is already covered by an excellent train line. That line could be made faster to be more competitive but it already handles far more passengers than air.
Now let’s look at some other popular routes.
Chicago to LA? 2,000 miles. That would take around 10 hours nonstop on the fastest high speed train. Make that even worse for New York to LA, and you can bundle in destinations like Denver, Las Vegas, Seattle, San Francisco, etc into those long distance routes that simply don’t make sense from an eastern city.
How about popular vacation routes, like Boston to Orlando? 1300 miles, so that’s at least 7 hours assuming the train never stops.
The new-ish Amtrak CEO is correct to focus on intercity routes that are between closely packed cities. The US does need more train routes similar to the Hiawatha Service or Northwest Corridor and they need to go faster.
But even this type of buildout will be limited when you consider the size of cities in the US. If you fly from Indianapolis to Pittsburgh you’ll be on a 50 seat jet or you’ll transfer to somewhere like Detroit. What sort of train carrying 50 people will be anywhere close to economically viable?
Sure, we could use some rail connection between something like Houston and Dallas but then those passengers will also have to rent a car or use a taxi frequently at their destination. At that point you are competing with individual driving.
Back to the Hiawatha Service, if I’ve got two people in my party it’d be cheaper to drive and possibly even Uber the entire way if I had four people in my party.
The leader in high speed rail, China, has nearly ideal conditions to work with. They have huge populations concentrated in dense urban areas with low car ownership. They have almost all major cities concentrated on on one coast. They have low labor costs and a centralized government structure that doesn’t have to consider property rights or environmental impact when building out infrastructure.