Co Antrim firm Mivan has won a £2.5m contract to fit out Ireland's answer to the Orient Express.
Around 40 of its craftsmen will be working on transforming Irish Rail carriages into luxurious cabins in a style said to reflect the Georgian architecture of Dublin.
The Belmond Grand Hibernian will launch on August 9, offering its well-heeled passengers two, four and six night trips from Dublin through the Republic and Northern Ireland.
Its two-night Northern Ireland leg - a destination dubbed 'the realm of giants' - will take travellers to Belfast for a visit to Titanic Belfast, and on to Bushmills and the Giant's Causeway. The trip costs £2,338.40.
The first Belfast-bound train departs on August 13 -but a spokeswoman for Belmond did not say if the disruption of security alerts on the cross-border line would be factored in.
The Belfast to Dublin rail line has been shut almost 30 times in three years due to bomb alerts, according to information released this month by the Department for Regional Development (DRD). There were two security alerts in 10 days last month. But she said: "The safety of our staff and passengers is of the utmost importance to us and remains a key factor in all of our planning.
"While we can't predict future disruptions to any trains that we operate throughout the world, we do remain in constant contact with local authorities in the countries that we operate to ensure any potential disruption to our guest experiences is minimised."
Belmond operates some of the world's most famous trains including the Venice Simplon-Orient-Express and Belmond Royal Scotsman. The Irish model is its seventh train.
Mivan is one of Northern Ireland's best-known fit-out companies, working on properties from cruise ships to the Scottish Parliament at Holyrood and one of Saddam Hussein's palaces in the 1980s. But it went into administration in 2014 and its assets including the company name, were bought over by Newry-based rival, MJM.
Gary Franklin, managing director of Belmond Train & Cruises, an international business specialising in luxury travel, said: "We chose to work with Mivan not only for their extensive experience but they have also shared our passion and vision for Belmond Grand Hibernian from the outset.
"It is very important to Belmond that we work with local experts and craftsmen to create a truly authentic train."
Mivan chief executive Neil Ward said the firm's expertise and experience on ships and hotels had helped clinch the deal - but a luxury train was a first. He said the train would rival "the great train journeys of Europe".
He added: "Mivan has a strong track record of delivering high end projects and we are delighted to be working on this prestigious contract."