Work to extend the Luas system through Dublin City Centre has been continuing in recent weeks as show in this latest pictorial update as provided by John Hampton.

New track has appeared in O'Connell Street in Dublin as part of the cross city tram route.On the left is the portico of the GPO and on the right the Spire which sits on the sight of the former Nelso's Column. O'Connell Street last had trams running along it in 1949.
I think the descriptions with the photo’s of O’Connell Street & Trinity College are crossed
Duly corrected – I got a little bit confused!
The spire is in O’Connell Street, standing where the Pillar used to be.
Is the extension only single track?
I believe it is single tracks running in opposite directions in parallel streets, a far cry from the double four-track terminus outside the General Post Office on the old broad-gauge system closed in 1949.
As Nigel says sections in the city centre have places where the tracks in either direction run along parallel streets. If you google “Luas Cross City Construction works” you will find a route map which shows the whole route including the outer section which runs along an abandoned railway track.