It's a wonderful idea ... in theory. But you are going to need far more than 67%.
There is a vast difference between Europe and the US and it's not just distance (let's face it, the entire European Continent is about the size of the east coast of the US and we are talking cross continent here which is vastly longer distances) but about the love of the automobile. Getting there is only half the problem; getting around once you get there is the other half. There are other things involved as well but the bottom line is that it is going to be very difficult to get a passenger rail system to be profitable in the US (in fact it never was). Most of the older railroads were built upon the backs of freight cargo and they died with the decision of the federal government to assist those veterans coming back from the European part of WWII who maintained the truck supply system. Using a vague excuse of national security and the desire for a whole lot of "runways" to land nuclear bomb carrying bombers they created the Eisenhower Interstate System which basically killed commercial freight.
High speed rail would basically form a similar problem to hub and spoke airport designs. With rare exceptions, (Etihad Airways is a good example of a hub and spoke system airline) this has been put aside by the airlines because the annoyances of having to go to the spoke in the first place (along with connecting flights) is more than having a slower and smaller place going directly from point A to point B. Now the rail system isn't a point to point system either so it's not a direct alternative to high speed rail lines, but rail still has to compete with air.
This is all before the necessary cost to implement the tracks. You have to get all new right of ways and whole new track infrastructure since the existing rail system is basically designed for freight because that is where the money is. When you add government it becomes a money pit.
Just one element of this would be
CASHR(California High-Speed Rail) ... approved in 2008, started in 2015 and the first segment won't be finished until 2027 with the first phase in 2033.
Using a base flying off the seat of my pants calculation, the proposal would be of an order of timescale as that of building pyramids and medieval cathedral construction.
