[CaliforniaKarl]

tarbism: To expand on what ZanyProgrammer said:

For most of the East-Bay-to-South-Bay segment (from Santa Clara to around Fremont), there is only one track. That's not unusual in freight rail, but what's missing here are passing points: Long sidings where one train can get out of the way of a passing train.

You can see the route around the bay here: https://www.youtube.com/watch?v=yoyZC4LvKoI

Also, Union Pacific owns the tracks used by the Capitol Corridor, so priority becomes a question: Yes, passenger rail is supposed to be higher priority, but UP can (and does) charge Amtrak for using the rails. Railroads can (and have) demand that passenger railroads pay to build/upgrade infrastructure as a condition for running more passenger trains.

So yes, it would be doable, but it would be _expensive_.

[ZanyProgrammer]

If you've been to Oakland BART, you've probably seen that in an around that part of Oakland, there are two sets of freight tracks, one set very rarely used.

But its irrelevant till you double track Alviso.

[tarbism]

I ride CC every day and it is not that often delayed by freight. But I will switch to BART when it opens in Milpitas because that will be faster and cheaper and with much more frequent service.