I haven't taken the Starlight north from San Jose in many many years, but I have taken the Capitol Corridor several times. I believe the standard route for passenger traffic is to get off the Mulford onto the old Dumbarton, making a "right" east to service the Fremont depot, then making a "left" at Niles Junction and using the "Oakland Sub" (UP's name) to Oakland via Hayward. I think the ACE trains go straight (to and from Altamont)onto the old WP from Niles Jct. Just looked at Google maps and there seems to be a single diamond in the Niles Jct. array, but not for the "left" onto the Oaland Sub. from Dumbarton (San Jose). Guess I'll go listen to the scanner.