You all have good points, and Bob's mention in passing of lanes on I-5 is very much to the point. Even at mid-day on a Sunday it's a solid train of trucks in the 2 right lanes (and sometimes the 3rd) flanked by people trying to do 85 up the hill and 100 down (doesn't work for me in a Prius - can only hold 70 or so). That said, the canyon gets a little tight in spots, and the EIS for a project like that could be a life's work for somebody. Would ANY rail over the Tehachapis (HS or otherwise) carry enough traffic to noticeably affect even just the growth rate on I-5?

Altamont is a puzzle. Yes, a tunnel could be done that avoids the worst of the faults and grades through the Pass itself. But that's not the only one needed - Niles Canyon will never be suitable without a really major re-do for fast trains even of the conventional sort. And the NIMBY issue will be significant. That said, Pacheco is probably worth considering only for full-on CAHSR (or Hyperloop); a more "reasonable" set of improvements would go a different way.

Coast definitely needs improvements, but they're of the spot variety in general. The MPOs out there need to work on a program like San Diego has of small jobs to extend sidings and add CTC spots; will take many years (SD has been at it for almost 20 years that I know of; oh BTW they also got sales taxes passed to help fund it) but eventually a decent railroad can be built piecemeal. Not high speed, though; the present line would have to be completely replaced for that to happen, which isn't in the cards for political, NIMBY, environmental impact, and cost reasons. Coast will just have to stay a bit laid-back.

I expressed this as alternative-universe thinking because the $10B for HSR has already been spent for practical purposes. I was just ranting that there might have been other ways to do something Really Useful (channeling Evil Thomas) with $10B of rail money if it were not necessary to shoot for 250mph. Thanks for the ideas.