Oops, sorry! Can't count properly!! There are now 32 Capitol Corridor trains (16 round trips - not the 12 round trips like I mentioned above) each weekday between Sacramento and Oakland as of the August 2006 schedule expansion. Then add in that west of Martinez on the Cal-P, the weekday count of passenger trains is now at 44 (32 Capitol Corridor, 8 San Joaquin, 2 Coast Starlight and 2 Calif Zephyr). Reopening the Moccoco Line from Tracy to Martinez would not help freight traffic avoid the most congested portion of the Cal-P west of Martinez. Besides, each month that passes means more interest by regional transit agencies to pay very big $$$ to the UP to turn the Moccoco Line into a passenger transit corridor (the e-BART now being discussed).
If you ever get the chance, check out Capitol Corridor's Managing Director Eugene Skoropowsi's blueprint for future track expansion. I got to see it this time last year during a combined ACE/CCJPA/UP meeting held on a special ACE train. It shows triple and even long sections of quadruple main track on the entire Capitol Corridor from Sacramento all the way to San Jose - except for the bottleneck of the double track Suisun Bay Bridge. It also includes a bypass of Niles Jct freight congestion by routing all of the Capitol Corridor trains onto the ex-WP from south Hayward (where the ex-WP fly-over of the ex-SP Hayward Line is) to the ex-WP Fremont Yard, where a new connection to the ex-SP Centerville mainline at Shinn will be built. This is how the idea of the Union City BART station to become a new BART/CCJPA/ACE(?)transit hub and the east end terminal of the proposed Dumbarton rail commute service to SF and San Jose is included in the Capitol Corridor/UP capacity expansion plans. Of course, this "little" Capitol Corridor project will cost the taxpayers of California well over $1 1/2 Billion to complete. As long as the UP retains dispatching control, why shouldn't the UP corporate personnel sit back and let government agencies pay the majority cost of capacity expansion as long as they still have the ex-WP Altamont route for the freight traffic that can't squeeze through the congestion on the ex-SP Cal-P? Paying for access to rail lines for expanding passenger service is now like a high stakes poker game, and the position of the SJRRC/ACE in retaining full unrestricted access to the ex-WP Altamont line is like that imaginary Texas poker player who comes to the table "with a big hat, but no cattle"...