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 (350

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)