Probably longer than that. France builds LGVs for a lot less than $20 million per mile. But we don’t even need a duplicate railroad; if the costs were kept under control (yeah, imagine that), it ought to cost a minuscule fraction in order to get average speeds into the triple digit range like they were talking back in the 1960s. Of course, nothing “out of the box” in Europe will be permitted to run in the USA thanks to the Federal Railroad Administration’s regulations regarding crashworthiness and other things . . .