DL 1661 then B6 159 at Boston
Washington National → Boston → Philadelphia
Timetable, Boston time
19:04DL 1661 from Washington National at the gate
19:00B6 159 to Philadelphia leaves the gate
23 h 56 apart on the timetable, overnight
B6 159 leaves 23 h 56 after DL 1661 arrives on the timetable: more than half a day, so not a connection we count.