Paris-Bordeaux was €15m per mile for electrified 200mph capable line. $20m / mile doesn't sound amazing for a non electrified line that operates at 79mph now and might have sections that operate at 125mph in the future.

> Paris-Bordeaux was €15m per mile for electrified 200mph capable line.

is that the LGV Sud Europe Atlantique between Tours and Bordeaux that opened in 2017? looks like thats €9B for 188 miles new track or €47M per mile.

https://en.wikipedia.org/wiki/LGV_Sud_Europe_Atlantique

> The consortium invested €3.8 billion, French government, local authorities and the European Union paid €3 billion and €1 billion was contributed by SNCF Réseau (subsidiary of SNCF). Another €1.2 billion was spent by SNCF Réseau on the construction of interconnecting lines, control centres, capacity enhancements at Bordeaux and remodelling the track layout at Gare Montparnasse.

Brightline goes exceptionally faster than the CA line, right now.

Is the current speed differential just because of the rock slides?

No, it's because Brightline exists and CA HSR doesn't, yet. So the speed is 125 mph to zero.

Right now it looks like the current top speed of Brightline is the same as most Amtrak lines in California (79mph). Brightline claims in the future it will have speeds up to 125mph. Conventional Amtrak trains already can go 110mph on sections of high quality track, and do in some places in the USA.

True, but the only place Amtrak gets close to that I know of in California is through Camp Pendleton, and there it maxes out at 90.

A "bright line" style upgrade to the SAN-LAX route would have been entirely worth it, and they're struggling along with it, but at pennies compared to what has been spent on HSR so far.