Unless noted in the public timetables, Amtrak trains arriving early at a station must wait until the scheduled departure time before leaving. This is doubly true at major stations such as San Jose, where passengers can connect from other Amtrak trains or public transit. When daylight savings time ends in the fall, trains that are running less than 1 hour late will wait at their next scheduled stop until time catches up. ( Except in AZ. & IN. )
Once upon a time when freight railroads ran their own passenger trains, it was not unusual to see notations in the public timetable that trains would leave intermediate stops early if all known passengers had boarded or disembarked. Of course this required a local agent to check with the onboard conductor.