For short distances high-speed rail can be a good option, particularly in connecting neighboring cities (LA-SF, etc).

The problems with all these projects are cost: Simple back of envelope calculations show it to be (a) dubious, or (b) possibly criminal (ie. standard taxpayer ripoff to cronies).

$64B - do the quick math on that. Figure a 30 year return on investment earning 4% per year:

$2.2B payback per year + operating cost of what? So somewhere around $7M per day in revenues minimum?

How many riders per day and what is average ticket price to make $7M per day?

I think you will suddenly find there are cheaper, faster, better options.