DL 5615 then DL 5665 at Boston
Louisville → Boston → Richmond
Timetable, Boston time
16:01DL 5615 from Louisville at the gate
15:23DL 5665 to Richmond leaves the gate
23 h 22 apart on the timetable, overnight
DL 5665 leaves 23 h 22 after DL 5615 arrives on the timetable: more than half a day, so not a connection we count.