Just seen this
Belfast Grand Central to Dublin Connolly: 06:00, 07:00*, 08:00, 09:00*, 10:00, 11:00*, 12:00, 13:00*, 14:00, 15:00*, 16:00, 17:00*, 18:00, 19:00, 21:00*
Dublin Connolly to Belfast Grand Central: 05:50*, 06:50, 07:40*, 08:50, 09:50*, 10:50, 11:50*, 12:50, 13:50*, 14:50, 15:50*, 16:50, 17:50*, 18:50, 20:50
Sundays
Belfast Grand Central to Dublin Connolly: 08:05~, 10:05, 12:05, 14:05*, 16:05, 17:05, 18:05, 20:05*
Dublin Connolly to Belfast Grand Central: 08:50*, 10:50, 12:50, 13:50, 14:50, 16:50, 18:50, 20:50*
The expanded service will be operated by the existing Enterprise fleet, trains from Iarnród Éireann’s expanded Intercity railcar fleet, and trains from Translink’s Regional Train fleet. The full timetable is available on the website