I agree the line is not designed for diesel-hauled trains. They would definitely not be able to maintain high speeds throughout. But it would be better than the freight line they run on now. Yes, the timing difference won't be dramatic, but if diesels are used it would be an interim thing (in theory) while extensions to the desired endpoints (not just the forced ones in the Valley) are figured out. We've done that with "freeways to nowhere" that were dropped, then picked up again 20-30 years later.

And yes, I also think that there's an fair to good chance that the Valley line is all we will ever see, for a long time if not forever. I certainly don't expect to live long enough to ride HSR from SF to LA. Cucamonga to Vegas, perhaps, but not the Big One. Thinking Big One, I'm seeing total construction time being on the order of the recurrence interval for a M8ish quake on the San Andreas ...