Luas opens at midday on Wednesday, with the launch by the Minister for Transport of the St Stephen's Green to Sandyford line, writes Tim O'Brien.
The launch is to be followed by five days of free travel for Dubliners before commercial operations begin on July 5th.
Pensioners and holders of free travel passes will continue to have free access. The second line, the city centre to Tallaght line, is due to begin operations in August.
Speaking in advance of the launch, the chief executive of the Railway Procurement Agency, Mr Frank Allen, said it was "regrettable" that Luas had been built as two separate lines. While he insisted he had no appetite for a political row, he said critics of the city centre section, including Dr Garret FitzGerald, were wrong, and the question of whether Luas would fit around the corner of Nassau and Dawson streets was a matter of geometry.
"On the matter of whether the tram can negotiate the corner, that is not a matter of opinion that is a matter of geometry, and on the geometry Garret FitzGerald was wrong," said Mr Allen.
He also revealed that the agency was already looking at increasing peak-hour frequency from five minutes to four.