The major similarities between the Bay Bridge and CAHSR are that they are big projects designed by politicians, with the designers and builders trying to make it work under pressure to deliver yesterday. As the Air Force knows well, that leads to cost overruns and quality under-runs. On the plus side for HSR, once the major design decisions are made the process of building it is fairly straightforward (if expensive) so with reasonable oversight the construction quality should be adequate. Except possibly for some stuff in the mountains, CAHSR isn't reinventing the wheel as was necessary for parts of the Bay Bridge. Politics will still apply, of course.

Politics (n.) - from the Greek root "poly" meaning "many," and "ticks," a small blood-sucking insect.