Trains are so huge in Europe thanks to the wars of the 17th-19th centuries.

America is roughly the same size and only now has half the population of Europe.

In 1800 Europe had about 150 million people. That’s about half the current population density of the USA for landmass BUT still extremely dense populations around the capital cities in the countries.

A nationalized train system was a lot easier for a individual nation the geographic size of Virginia with the a population larger than current US states.

Especially when your neighbor is invading you every 20 years.

American Rail during the civil war helped the north dominate the south (though the rivers of the USA may have been even more beneficial for the north) BUT showed the need for off rail transport and helped usher in the military application of wheeled and tracked vehicles that can go off rail. Weird how that works.