The first Enterprise train testing took place at Belfast Grand Central Station as the wait continues for rail services to launch at the £340m public transport hub.
The new bus and train station opened to the public earlier this month, with the first buses running from 8 September.
Train services due to start later this year once rail safety checks have been completed, although no date has yet been confirmed for this.
The first trains began testing last month.
A Translink Spokesperson said: “The first Enterprise train testing took place at Belfast Grand Central Station on Sunday morning,
“An hourly service is planned for the flagship service which will see 15 trains leave the world-class integrated travel hub for Dublin every day - a total of 30 running in both directions.
“This move will make it easier, more convenient and flexible for people to consider the train as their sustainable travel option and help advance climate goals.”
