The Surfliner in Southern California is a great deal. Take the business class ticket. OC to San Diego is a breeze and you can relax and enjoy all beach towns with a glass of wine. Took it from OC to Santa Barbara. It takes about an hour longer than driving but so worth it. Can’t say enough good things about it. Views in all directions totally amazing. Trains are packed at times but it’s good to see.
I think high speed cross country rail travel is not very practical either to build or for travelers. The distances are too large, terrain too difficult and population densities are too low west of the Mississippi. It’s worth noting that the US train network is optimized for freight and we carry much more freight than many countries by rail.
High population density corridors like BOS-NYC-PHL-DC and SB-LA-OC-SD make a lot of sense and would be great to see even better service. We are seeing a high-speed, private service building track between Ontario, CA and Las Vegas. Distances to Vegas and Phoenix are short enough and population densities high enough that it makes travel by train from SoCal competitive with driving and air.