BART also runs under the bay. If they blow something up there it could blow a hole in the tube thus winding up with the bay in the tunnel. I'm not sure how many people are on one train??
I do not know how many, but a bus will hold 50 or 60, maybe
more. I am talking about the Casino trip buses, we would prepare "fun packs" for them.
I have not been to San Francisco for 50 years, so was not aware it went under the bay.