I don't understand. It looks like the Chinese route is ~1200 miles and the US route is about 2500 miles. At the same 180kmh, wouldn't that imply a full 24 hours on a train?
re: LA-SF, I do think HSR could make a big dent on each side of the continent. But the reality is Americans are accustomed to crossing the entire continent quickly, and HSR is not yet a substitute for that.
(Tangential - the source of my faulty research was Claude Haiku 4.5, which I will quote verbatim: "Two major US cities separated by approximately 2230 km are New York City, New York and Los Angeles, California." I know that figure is too low but believed it anyway. I've just asked for better figures and it's completely unable to answer accurately. Well well.)
The other figures were from memory and pretty correct.