Much as I dislike BART's broad guage and their habit of DOD style spending ($72 allen wrenches...) the fact is that their lightweight cars make rail across the GG Bridge feasible. (As I have cited before on this forum, Louise Dyble's comprehensive history notes that the bridge was built with the capability of using NWP's existing cars which weighed much more than BART cars do.) As to "10 cattlecar trains" that is more a question of how many businesses continue to insist that EVERYONE needs to be in the same building (campus) in order to be productive and where that should be.
We are stuck with two incompatible rail systems. boo hoo. The New York metro is stuck w/ five if you count different voltages on the catenary systems. It increases costs, but does not prevent travel.
We need more non automobile travel options.