UA 471 then DL 1734 at Atlanta
Washington → Atlanta → Toronto
Timetable, Atlanta time
14:36UA 471 from Washington at the gate
14:07DL 1734 to Toronto leaves the gate
23 h 31 apart on the timetable, overnight
DL 1734 leaves 23 h 31 after UA 471 arrives on the timetable: more than half a day, so not a connection we count.