FR 9673 then IB 421 at Madrid
Rome → Madrid → Barcelona
Timetable, Madrid time
23:30FR 9673 from Rome at the gate
18:00IB 421 to Barcelona leaves the gatealso IB 421S, LL 3021, VY 5122, AV 6170, QR 6971
18 h 30 apart on the timetable, overnight
IB 421 leaves 18 h 30 after FR 9673 arrives on the timetable: more than half a day, so not a connection we count.