No you are right, this is actually both caltrain and the high speed rail. These two will interline in the bay area starting in Gilroy (which also has a station, making the station count 5 actually). SOMA is the current terminus of Caltrain. There are plans to connect to the downtown transbay transit center (I refuse to call it Salesforce transit center) but there are no estimates to when the downtown extension (DTX) will be completed to allow that. CAHSR actually finishes before DTX (which is a real possibility) then SOMA will be the terminus of CAHSR as well until the DTX finishes. However I wouldn’t be surprised if SOMA will be skipped by all but hyper-local trains ones DTX is ready.