In order for the Metro north to proceed, the book of reference for the RPA's draft railway order identifies hundreds of properties which it will have to tunnel underneath.

This will be achieved by acquiring "substratum" land from private homes, schools, churches, and public parks in areas along the proposed route such as Griffith Avenue and Botanic Avenue in Drumcondra, St Ignatius Road in Phibsborough, Parnell Square and parts of Dublin 7.

It will also include the acquisition of land underneath some of the city centre's best known businesses.

Among the retailers which are identified for potential acquisition of "substratum lands" are Arnotts, Clerys and Easons, and a range of other businesses on O'Connell Street, Grafton Street and elsewhere.

Meanwhile, underground lands owned by Trinity College, Dublin City University, St Patrick's College in Drumcondra as well as lands at Dublin Airport are also identified for potential acquisition.

The RPA has set up a Property Owners' Protection Scheme for residents whose property lies within 30 metres of the edge of the tunnels or 50 metres of the underground stations. It says this aims to provide a "simple and prompt way of rectifying any damage caused under the project up to the ceiling of €30,000."

However, in written submissions to An Bord Pleanála, a number of private residents who would be affected by any tunnelling works, express their unease.

A submission by the Iona and District Residents' Association, which expresses support for the project, also outlines a number of potential concerns.

This includes the impact of construction traffic and construction vibration around Drumcondra station.

Quinn's of Drumcondra, a well known local pub, goes far further, expressing "enormous concerns" about the future "value and viability" of its business premises due to the "short term and possible long term loss of land and substratum" and the disruption during construction works.

Others, such as the five star Westbury Hotel and Mall, also express disquiet about the potential "unacceptable noise and vibration levels" and their effect on their guests.

However, at least one major city centre retailer, Arnotts, says it is "very supportive" of the project as it believes it will "greatly enhance the transport system" in the city, although it does ask that the programme of construction be kept to an "absolute minimum."

By comparison, a number of others, including the Dublin City Business Association, which represents city centre businesses, are critical of the proposals.

Clerys says it believes that "the building of Metro North presents a great threat to the retail life of the city" and seeks more information on a number of issues.

"We are concerned that this project may well prove unnecessarily damaging to the existing economy as well as prove to be the least cost efficient means of achieving what we all agree is a necessary project," the DCBA submission concludes.