Originally Posted by scillyisles

Both the train and walk option at SFO require you to exit security and be re-screened at the International terminal.
When you come off the AA flight then you follow the signs to exit which brings you out at the lower level. You then have to go back up to departures level on an escalator - it is at this point that you can choose to walk around the departures level to the International terminal. If not then you take another two escalators up to the train and wait for the correct train which is a Red line one.