Capitol Corridor is just a few trips a day, so is not useful for rapid-transit mobility within the Bay Area. Indeed, it runs so rarely that it’s almost misleading to represent it as a line on the map.

To run a serious rapid-transit frequency on the rail line in this Oakland-San Jose corridor, you’d need tracks completely separated from freight. The Caltrain line on the peninsula has almost no freight, because rail-dependent port functions have almost completely disappeared from San Francisco. However, Oakland is the major port for Northern California, so the tracks between Oakland and San Jose deal with very heavy freight demands.

Remember too that climate-change objectives would suggest that we need to be expanding freight rail at the expense of trucking. For high-volume movements, even diesel-powered freight rail is much more emissions-efficient than trucking. So we’ll need more freight rail capacity, and transit advocates need to keep this in mind when imagining transit uses for existing rail tracks.

Given this, a Caltrain east project might be workable, but it would not be as cheap as it sounds. It would also have to make a very, very good connection to BART, so that passengers could connect with BART to get to very high-demand destinations like Downtown Berkeley, which are on BART but not on the standard-gauge rail network. This would probably need to be at Coliseum station, which is the only point south of Oakland where the lines are right next to each other.

So it’s possible, but it’s not simple or obvious.

http://sfcityscape.com/maps/bay_area_rail.html

I understand that there is need for commuter services south to San Jose. I’ve also read that BART trains are at capacity between SF and Oakland… If you upgrade the ACE and Capitol Corridor trains you serve a wider area into San Jose and may get some people off BART and onto “Caltrain East” going north. I haven’t checked Google… Did UP and it’s predecessors have the foresight to get a ROW wide enough for four tracks like they did on the Peninsula?

“….only BART can provide a single north-south rapid transit corridor that extends the length of the East Bay, linking San Jose, Oakland, and Berkeley….

I may be reading the map wrong but it looks to me like the Capitol Corridor is already doing it. In the future four track it, expresses to Sacramento and build infill stations to serve local traffic between East Bay suburbs and San Jose or Oakland/Berkeley.

There’s additional bonuses to doing that. Commuters on the ACE corridor get a faster commute to San Jose. People in San Jose get faster service to Oakland and Sacramento. Gives everybody between Richmond and San Jose an alternative to BART….

I agree with Ian that Bay Rail Alliance is a good source on this. (It’s actually descended from an organisation called Peninsula Rail 2000, which I led for a couple of years around 1990.)

I read that for the same capacity, a BART trainset costs 40% MORE than a TGV. That’s expensive. Can’t find the exact quote, but here’s this from http://www.bayrailalliance.org/q_why_not_replace_caltrain_bart_wont_cost_same_ele

“BART is a one-off system that requires custom-made trains that are incompatible with the worldwide standard that Caltrain electrification will follow. This decreases competition to build BART trains and increases BART’s cost. Caltrain, on the other hand, can operate off-the-shelf equipment produced by a variety of manufacturers worldwide. In fact, some of the nicest amenity-filled high-speed trains in Europe cost less to build than a BART train does.”

However, the Caltrain East plan would have been much less expensive… (and faster than Light Rail) and it would use standard gauge tracks which could be shared with other train services. You get much more flexibility that way, allowing flexible configurations of commuter and eventually, full-metro services. Caltrain electrification means the peninsula is going to start behaving more like a metro service, and doing the same on that corridor might mean that the shiny new CA HSR trains could run up to the East Bay on the same tracks. Or at least, Amtrak rapid rail.

“BART is such an expensive technology to extend and some aspects of the technology are obsolete.”

San Francisco is not the primary commute destination that the BART extension has in mind. People in the affected areas of Fremont, Milpitas and San Jose are much more likely to be commuting to nearby Silicon Valley or San Jose than to San Francisco.

The only justification for building BART here (as opposed to, say, a much cheaper but slower project of extending VTA LRT northward) is that only BART can provide a single north-south rapid transit corridor that extends the length of the East Bay, linking San Jose, Oakland, and Berkeley.

I’m personally somewhere between ambivalent and negative toward the BART extension, mostly because BART is such an expensive technology to extend and some aspects of the technology are obsolete. But if the project is going ahead anyway, there is some logic to going to Berryessa first, because it gets transit riders past one of the worst chokepoints in the East Bay freeway system, which occurs on I-880 and to a lesser extent I-680 around the county line (between Milpitas and Fremont). Creating transit-only routes through road network chokepoints is often a very good investment, because the resulting transit line will be competitive with cars even if transfers are then required to reach ultimate destinations — as will almost always be the case for the spread-out employment of Silicon Valley anyway.

Again, this is not to endorse the project. LRT or even BRT could have met many of the needs that the BART extension will serve. But the geography is quite different, and in ways more favorable, than your narrative would suggest.