I don't guess you could do it where there are steep grades, but why couldn't we put in high-speed rail trunks along (in the median of) existing Interstate Highways? Curves might need to be widened out, perhaps, although banked curves would help a lot there. I would think that if long straight stretches of high-speed rail could be put together that way, and it obviously worked, then maybe resistance to connecting those into major cities might lessen as folks there realized what they would gain. High-speed rail would certainly make a LOT less noise, and what noise it did make would have a much smaller footprint, compared to umpteen square miles surrounding any major airport, and perhaps you could help sell the idea at least partly by dangling the carrot of reduced air traffic (and noise) at the local jetport as high speed rail starts to siphon off some of the traffic. And although I really don't know, I would guess that with proper engineering, it should be possible to handle a much steeper grade with high-speed rail than a freight could, so except for where there are tunnels (on the Interstates), or lots of rolling hills (think "roller-coaster") maybe this could work. Run it to just outside the city on the interstate and provide "alternate transportation", at least initially, into the cities. Intersect with existing pax rail into the cities, with a bi-or-tri-modal station, if that option is available. Using Interstate Right-Of-Way should sharply reduce the costs to initially install, and cut down the lead time, since eminent domain wouldn't be required - the Interstates are already government property as far as I know. It would still require a huge capital outlay, but not nearly as much as buying up all that land to run it downtown and through completely new corridors would. And maybe a couple of specific demonstration city pairs could be researched and chosen as being the ones most likely to immediately start paying for themselves with lots of ridership. Dallas/Houston/San Antonio come to mind, or maybe Atlanta-Tampa-Miami, Chicago-St.Louis, or ????? Certainly that's what you'd need to sell it to the rest of the Country. We need a Super-Whopper-Turbocharged Megaball Lottery, with a 50-Trillion$ payoff, with the winner being high-speed rail.