How to plan rail transportation? You build it to get people to the nearest 20 miles (or 50 miles in truly unpopulated areas). You make ubiquitous electric cars available (self-driving or self-drive) at the nodes to get people the last mile to their destination.

20-50 miles falls within the range requirements of even inexpensive electric cars, even in hot/cold weather where battery life is drastically reduced.

In more populated areas, you increase the density to 5 miles in exurbs, a mile in older-type suburbs, so on till you get to larger cities.

And you don’t run trains as we know them. You run smaller autonomous vehicles that can form trains and be flexible as far as routing. They don’t have to refuel/recharge, they don’t have batteries to degrade.

And you agree on a common electrical system rather than the mishmash we have in the US right now. 25,000 volts AC outside of city centers, 1000 or 600 volts DC in cities and underground.