There's daily trains from LA to San Jose (which is actually bigger in terms of population than SF). You can then connect on commuter rail to SF. Not ideal, bu

There's daily trains from LA to San Jose (which is actually bigger in terms of population than SF). You can then connect on commuter rail to SF. Not ideal, but an option. I think the reasoning is that SF would be either a dead end for a train line, due to the whole peninsula thing, or an expensive place to build a rail line out of, across the bay.