DL 5592 then DL 5665 at Boston
Washington National → Boston → Richmond
Timetable, Boston time
15:21DL 5592 from Washington National at the gate
15:20DL 5665 to Richmond leaves the gate
23 h 59 apart on the timetable, overnight
DL 5665 leaves 23 h 59 after DL 5592 arrives on the timetable: more than half a day, so not a connection we count.