So ... working forward from that ... give it 3-5 years for detailed design, and 5-8 years for acquiring right of way while doing the design (btw under federal rules they can't even accept land donations until the ROD is done). Then, if the money is there, they can start building (yes, I know, in the Valley they started building before buying all the right of way; that was a dumb move that cost construction delays and a lot of extra money, but was kind of forced by a couple of political problems, and should not be a standard way of doing things). A long tunnel through the Coast Range won't happen overnight - give it at least 5 years by itself, plus the rest of the work.

Allowing for the usual hiccups, and assuming the money is there (which is unlikely), construction might start (with a 2021 ROD) around 2030, and take 8-10 years to finish and be usable. So 2040, minimum, to be open for service, again assuming the money is there to go beyond ROD.

Those are not pessimistic assumptions; they're realistic for a big project with a big tunnel, assuming the money is there or can be reasonably expected when needed (i.e. the program for providing the money is in place). The ROD is the end of the environmental and preliminary engineering process (i.e. Project Approval), and the beginning of the middle part of the project development process (Design and Right of Way).