Standard "heavy rail" Amtrak (think: Pacific Surfliner, two stories tall with thundering diesel, https://www.pacificsurfliner.com/plan-your-trip/ ) can run at 120 MPH if the track has positive track control. By some definitions that makes it "high speed rail" heh.

Which the Surfliner didn't in my day (and I think it still doesn't) - but it would hit 90 MPH through Camp Pendleton and I swear my GPS clocked it at 100 once.

Still would beat a car LA station to San Diego station during rush hour traffic.