The route of the planned new Luas through west Dublin was unveiled yesterday with tram lines running from Trinity College to Lucan.
Operators expect an extra 25 million commuters to use the growing network -- but it could be early 2011 before work begins.
Journey times are expected to be around 45 minutes on the 15km route.
A spokesman for the Railway Procurement Agency said: "We would expect that journey times would be similar to the Tallaght journey. We would expect around 45 minutes.''
No price tag has been put on the huge project, but planners insisted that they are aiming to minimise disruption in the city.
"We would have to speed up time spent building the lines, that would be our intention, and we have already done that with the Docklands,'' the RPA spokesman said.
"The man in the street might have felt we left areas unfinished during construction.
"We would certainly be more focused on limiting any disruption in all areas, but particularly the likes of Thomas Street and Dean Street.''
The 15km Line F will start on College Green heading west along Dame Street to Christchurch before joining the existing Red Line at Fatima or St James's Hospital.
Five stops later trams will continue west into Ballyfermot through Cherry Orchard and out of the city to Liffey Valley and a possible park and ride before stopping at Quarryvale, Castle Road, Griffeen Valley and the Newcastle Road.
It is also planned to build stops linking with the proposed Metro West and Metro North, rail and bus services.
Specific details on locations of stops have to be finalised in the coming months before a railway order is submitted in July 2010.