A3 961 then TK 1848 at Athens
Bucharest → Athens → Istanbul
Timetable, Athens time
11:50A3 961 from Bucharest at the gate
06:55TK 1848 to Istanbul leaves the gate
19 h 05 apart on the timetable, overnight
TK 1848 leaves 19 h 05 after A3 961 arrives on the timetable: more than half a day, so not a connection we count.