I’m desperately hoping that the greenfield Charlotte-Atlanta route is designed and built for 220mph electrified service, as mentioned in the study as a possibility. Even though I know it would take a lot to build that, if you’re going to greenfield entirely new infrastructure between two of the country’s fastest growing cities, shooting for diesel trains at 125mph seems absurd thinking decades/centuries into the future.
Plus, I have to imagine that (in 50 years or whatever), if there is electrified, 220mph service from ATL-CLT, the rest of the distance from CLT-RGH-DC will be electrified and upgraded too. (Personally, I love @orulz 's idea of a greenfield CLT-RGH high-speed route in addition to regional trains on the current NCRR.)
Maybe CAHSR will be a great success when complete and inspire NC/SC/GA to aim big.