B6 2120 then B6 1955 at Boston
San Diego → Boston → Washington National
Timetable, Boston time
05:00B6 2120 from San Diego at the gate
17:10B6 1955 to Washington National leaves the gate
12 h 10 apart on the timetable
B6 1955 leaves 12 h 10 after B6 2120 arrives on the timetable: more than half a day, so not a connection we count.