The unused ticket belonged to the grandmother of Illinois woman Margaret Hallem, who produced it at the Smithsonian Folklife Festival in Washington DC while checking up on her Ulster roots.

She told Philip McDermott, from the University of Ulster, that her grandmother had been due to sail on the Belfast-built White Star liner but missed the trip due to bad weather.

“It is always amazing to hear the stories of people searching for their family histories. This one was a bit special,” said Valerie Adams from the Public Records Office Northern Ireland.

“We have talked to more than 4,000 people since the start of the festival and it has been a wonderful experience.”

Texans, Californians and Canadians have all traced their roots back to Northern Ireland.

The genealogists have provided inquirers with help using a number of sources, including databases at the PRONI, the Ulster Historical Foundation and the Centre for Migration Studies.

Arriving with varying degrees of detail, many of the visitors have been trying to find the origins of their family names.

Others have provided very specific information which has often resulted in records being found of family births, deaths and marriages.

Christine McIvor, of the Centre for Migration Studies, said: “The combination of the three databases has been a brilliant tool kit for us and has helped us provide a real service to visitors to our marquee.”