The interstate standard max grade is 6% and that’s only used when there’s no other option over mountains. The limit for standard passenger trains seems yo be 4-5%. So it’s not that different, the vast majority of the interstate corridor could support passenger trains. Not freight trains through, those need a much gentler grade.
The US has essentially built a railway network with the interstates, it’s just paved over and less efficient.
Also for the extreme cases, don’t forget cog railways. The steepest one is Pilatus railway with maximum gradient of 48%. Good luck trying something like that with a car.
The interstate standard max grade is 6% and that’s only used when there’s no other option over mountains. The limit for standard passenger trains seems yo be 4-5%. So it’s not that different, the vast majority of the interstate corridor could support passenger trains. Not freight trains through, those need a much gentler grade.
The US has essentially built a railway network with the interstates, it’s just paved over and less efficient.
Also for the extreme cases, don’t forget cog railways. The steepest one is Pilatus railway with maximum gradient of 48%. Good luck trying something like that with a car.