Transport Infrastructure Ireland (TII) is to begin surveying properties on the proposed MetroLink corridor from March to collect "baseline information".
TII has written to 140 properties along the corridor about conducting a “preliminary buildings and structures survey”.
The rail line, which is due to run every two minutes from Swords to Sandyford, is expected to open in 2027.
A letter, which has been seen by The Irish Times, states: "We have selected your property for the survey as it is a representative example of a specific type of building stock, structure of public importance, or structure that has potential to be affected by the proposed project.
“The choice of your property for the preliminary building and structural survey is in no way indicative of potential impacts from the proposed project.”
TII said the surveys will be used to inform the Environmental Impact Assessment for the scheme and the construction and operational phase design “to ensure that any potential impacts from the scheme are minimised”.
The preferred route of the metro line, which combines the previously planned Metro North from Swords to the city centre with an upgrade of the Luas Green line between Charlemont and Sandyford, was announced last March.
At that time it was revealed around 100 properties may have to be acquired and demolished to facilitate the rail line if the preferred route went ahead, including 70 apartments at the College Gate complex on Tara Street.
In Ranelagh, houses on the west side of Dartmouth Square stand to lose parts of their back gardens, while two houses on Dartmouth Road may require demolition.
In Glasnevin 20 properties near Cross Guns Bridge are also likely to be required to facilitate the line.
A revised route of the line is expected to be published next month and a further round of public consultation will begin.
