THE RAILWAY Procurement Agency (RPA) is to go ahead with a low-capacity design for Metro North, according to briefing documents circulated to the four consortiums which are bidding for the project. Tim O'Brienreports.
The agency confirmed to bidders at a specially organised "workshop" in recent weeks that it wanted to develop an underground which uses vehicles that are longer but similar in width and height to the overground Luas trams.
The Luas has already faced criticism from commentators, including Dr Garret FitzGerald, who say its current capacity problems relate to the fact that it is a lower-capacity tram system rather than a heavy-rail metro line.
However, the Green Line Luas was constructed so that it could be converted to a heavy-rail metro line by the addition of faster, wider-bodied carriages - at least from the Beechwood stop outbound.
However concern has been expressed that such an approach would not be possible under ground, unless the tunnel was constructed to a wider specification than that which has been indicated in the pre-tender advice given to the bidding companies at the workshop.
The agency's specification envisages a maximum 18,000-20,000 passengers an hour in each direction, in what would essentially be a 90m (295ft) underground tram.
In contrast, the overground Dart has a capacity of at least 36,000 passengers per direction per hour.
In a further difficulty for Metro North, its catchment area is much wider than the coastal Dart line, encompassing much of the mid-city, and taking in major installations such as the Mater hospital and its future extensions, DCU, Dublin airport and the expanding Fingal area of north Dublin.
RPA chief executive Frank Allen has said Metro North is fully compliant with population projections in the Fingal Development Plan.
However, the Dublin Institute of Technology Futures Academy has calculated that more than one million people could migrate to the Dublin-Belfast axis by 2020.
This would create additional development pressure beyond the Fingal administrative area, which would critically affect the usage projections for Metro North.
Faced with the problem, Minister for Transport Noel Dempsey has decided against asking the Railway Procurement Agency to build additional capacity in the Metro North tunnel, a feature he acknowledged would affect the cost.
However, Mr Dempsey failed to give the agency's plans his outright blessing, remarking that he "could not guarantee" that the capacity of the proposed Metro North was sufficient to meet population forecasts.
Speaking at the recent launch of plans for the CIÉ's underground Dart interconnector, which will use the wider-bodied trains, Mr Dempsey said he had been assured by the RPA that Metro North had sufficient capacity and, while he acknowledged that there were industry concerns about the issue, "the time for consultation and talking is finished".
The agency expects to issue tender documents to the bidders by May.