It was due to finish in 2027.
The long awaited Dart extension to Kildare and MetroLink projects, which were due to be completed by 2027, are set to be delayed again.
The Irish Mail reports construction on the Dublin projects won't now begin until that date.
It highlights 2032 as a completion date for the Dart Plus extension, to Maynooth, and 2034 at the earliest for MetroLink.
TD for Dublin North-West, Dessie Ellis, says the delays would also add "substantially" to the costs
Details of the delays were revealed at a Cabinet meeting in July, the same one that discussed the UN appointment of Katherine Zappone.
Seanad Leader Regina Doherty says a further delay on these projects is "disgraceful" and is not acceptable
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