BART and Amtrak are teaming up on assessing the possibility of building a second Bay Area crossing, one that would give passengers a “one-seat” ride on the Capitol Corridor train from downtown San Francisco to Sacramento.
The idea is to build a Second Transbay Tube (or tunnels) with four tracks.
One pair of tracks would be dedicated to BART, using the wider gauge track and short trains so it can connect into the existing system, even allowing BART to reroute trains from one tube to the other.
The other pair of tracks would be the standard-gauge conventional rail tracks used by Caltrain, Capitol Corridor, and Amtrak.
One plan under consideration would be to add a new Capitol Corridor line that would run through the East Bay and then feed directly into San Francisco, possibly into the Transbay Transit Center at Mission and Beale streets.
This doesn't need to be limited to the Capitol Corridor.
Going the other direction, Caltrain could continue on from San Francisco to Oakland, Berkeley, or all the way to Sacramento on those same standard-gauge tracks.
