DL 5615 then DL 5619 at Boston
Louisville → Boston → Milwaukee
Timetable, Boston time
16:01DL 5615 from Louisville at the gate
15:40DL 5619 to Milwaukee leaves the gate
23 h 39 apart on the timetable, overnight
DL 5619 leaves 23 h 39 after DL 5615 arrives on the timetable: more than half a day, so not a connection we count.