The proposed southside leg of the long-awaited MetroLink line is set to be massively curtailed.
The line will not go all the way to Sandyford, as originally planned, as a result of opposition from residents and fears of years of disruption to the Luas Green Line.
Meanwhile, the Irish Independent has learned that on the northside, facilities for Na Fianna and Ballymun Kickhams GAA clubs are set to be protected.
Key details of the new plan include:
:: The Metro will run from Swords to Charlemont Street to meet the existing Luas service. The Metro will not continue down the Green Line to Sandyford, as had been proposed.
:: Underground drilling is to continue as far as Ranelagh to allow for future expansion.
:: Green Line Luas services are to be upgraded over the next decade to allow for a 55m tram every two minutes.
:: The tunnel will be single bore.
It is understood the preferred route will be announced by the National Transport Authority and Transport Infrastructure Ireland today.
However, a fresh period of public consultation is to run until mid-May. The project will then move quickly to the planning stage.
In what is likely to be a controversial move, it is now proposed that tunnel boring will be completed through Ranelagh even though the Metro won't go to the village.
Sources said it will be cheaper to keep tunnelling now to allow for expansion.
However, one source indicated the extended tunnel would be unlikely to come into use before 2038.
The cost of the shorter Metro line is unclear at this stage. An international expert in megaproject planning and management, Professor Bent Flyvbjerg from Denmark, is to be brought in to oversee the costings.
The original proposed route from Swords to Sandyford sparked controversy on both sides of the city when it was announced last year.
There were complaints from some residents in Ranelagh who objected to the closure of a road from Dunville Avenue to Beechwood Road during construction.
Another option that emerged last month - a plan to bring the route underground through Ranelagh in a bid to pacify residents - could have seen the Luas Green Line closed for up to four years. This option was ruled out by Transport Minister Shane Ross as "completely and utterly unacceptable".
In the new plan, Na Fianna GAA Club will no longer lose three pitches for up to six years while the MetroLink is being built. Also, the metro station for the area will now be located on a pitch used by soccer club Home Farm.