I'd like to see it thoroughly planned out, and a real cost estimate. Most of the trip is plainsland...simple. Getting through the Rockies, way more complicated. I've tried to read on the subject but estimates are an order of magnitude off between projects.

All that said, of course, figuring out how to lower costs safely would be a great thing.

The Rockies are the big obstacle of course, but the stretch east of the Mississippi is also problematic... hard to go around all the towns, and you've also got to cross the Appalachians and/or Alleghenies.

> High speed rail is well $100m/mile, just for the track.

That's frankly an insane figure, and depends vastly on what you're building and where. For something that's largely running through rural landscape, you really should expect no more than half that for the total construction cost. Maybe US construction is that expensive, but… wow.

If we're talking east-west in the US, there are two major mountain ranges, many smaller ones, vast deserts, let alone getting contiguous land in the East.

At those prices you can build the railway with maglev technology. I don't think these costs are realistic.

That seems too high. I'd rather say in the order of c.$100bn.

In France the average cost is €15m/km, and that's for extremely high standards / constraints (350km/h or 220mph nominal speed, incl. barriers & bridges for wildlife)