Train services will not begin at Belfast's new bus and train station until rail safety checks have been completed, Translink's chief executive has said.
It was announced on Monday that Grand Central Station will open to the public next month, with the first buses running from 8 September.
But Translink's chief executive Chris Conway told the BBC's Good Morning Ulster programme he was not yet able to confirm when train services would begin.
He explained the rail facilities "have to be approved by the safety authority" but he added that he hoped to be able to announce a rail launch date "soon".
Mr Conway said Grand Central was a "complex station to open" and there was "a lot of training required" so that staff can ensure public safety from the start.
Rail passengers have faced disruption since the nearby Great Victoria Street train station closed permanently in May.
That site had served Belfast for almost 200 years, but it is being replaced by a much larger integrated bus and rail hub a short distance away at the Grand Central site.
To facilitate the changes, the train track between Belfast and Lisburn has been closed for the summer.
This closure has also affected the cross-border Enterprise service, which is running bus substitution services between Belfast and Newry.
Mr Conway was asked about the disruption which will continue into the new school term in September.
"It's the largest infrastructure project on the island of Ireland and therefore needs careful management as move to the opening phases," he said.
"We've laid over 6km of new track. We've implemented a brand new digital signalling system and a new contactless system with automatic gates and barriers."
Mr Conway explained that all of the new equipment required testing and training for railway workers.
"But most importantly we have a safety authorisation process to go through and the safety authority have to have their say on that," he added.
"Therefore we're doing a phased opening to make sure it's safe for everyone and to make sure everyone gets used to the new facilities."
The Translink boss was also asked about the cost of the project, which has spiralled in recent years.
Early predictions had put the cost of delivering the project at £200m.
But in April this year, Infrastructure Minister John O'Dowd told Stormont that the latest cost estimate had risen to £340m.
Mr Conway told the programme: "The full business case was signed off in 2022 at £300m.
"Since then we've had extraordinary inflation and we intend to bring it in at around 10 to 15% increase on that.
"That's an exceptional achievement by the teams, given the extraordinary inflation that we've seen since then."
"But in terms of value for money, this will totally modernise our entire public transport network," he added.
Last month, the final report of the All-Island Strategic Rail Review made 32 recommendations to improve train services across the island of Ireland.
These included connecting Dublin, Shannon and Belfast International airports to the rail network and a proposed new station at Craigavon.
Mr Conway said the new transport hub at Grand Central "is needed to enable a lot of those features" that were proposed in the review
The chief executive added that the public "will be excited by what they see" when Grand Central opens next month.
He said it will have "very modern, advanced features" including contactless ticketing and improved passenger accessibility.
Mr Conway added that new business outlets would help to regenerate the city.
2024-08-20T10:24:02Z dg43tfdfdgfd