PUTTING Luas underground in the centre of Dublin could cost up to twice as much as the on street proposal favoured by CIE and delay the project for two years which means that it would fail to meet the deadline to qualify for EU funding.
This is one of the principal conclusions of the multivolume Environmental Impact Statement (EIS) submitted last Thursday to the Minister for Transport, Mr Dukes, along with CIE's application for approval to proceed with the £229 million project.
"The costs of constructing an underground are at this stage little more than notional," according to the EIS. "There is also a high degree of risk associated with this due in part to the lack of detailed information on the geotechnical conditions in the city centre."
It says the supporters of the underground option - who include the former Taoiseach Dr Garret FitzGerald, and Senator David Norris - have not taken full account of all the likely costs (capital and operating) associated with underground services.
These included "very substantial" costs to relocate utilities - electricity, gas, telecommunications, water and sewerage lines - especially in the case of "cut and cover" or shallow bored tunnels. (These costs are already included in the Luas budget.)
The EIS, which is the most comprehensive and detailed study yet presented for any project in the State, also says the estimated £12 million cost of underground stations has been underestimated, adding that building them would be "particularly difficult".
"The construction timetable for an underground would be substantially longer than that for an onstreet LRT (light rail transit) system," it says. Each of the eight underground stations proposed by the promoters of this option would take about 18 months to build.
"Under these circumstances, the overall schedule for the project would be approximately two years longer than the onstreet option," the EIS says. This would mean a completion date of 2003 - long after the current tranche of EU Structural Funds runs out.
Even a short length of tunnel, between Westmoreland Street and St Stephen's Green, would add an additional £27 million to the cost of the project. Putting the entire city centre stretch of the Luas underground within the canal ring would cost an extra £308 million.
The EIS emphasises that these are "conservative" estimates. "Budgetary constraints do apply and the additional expenditure cannot be justified either on financial or on economic grounds," it says, adding that it would also be contrary to the city's transport strategy.
"The on street proposal ... has both `carrot and stick' components in that it makes public transport more attractive while introducing significant levels of general traffic restraint in the city centre in line with the DTI (Dublin Transportation Initiative) strategy."
Though it concedes that an underground would have "positive decongestion benefits", the fact that it would retain the street surface of the city centre in its existing configuration to accommodate more private cars "is not in keeping with the DTI strategy".
The EIS also argues that, since the underground option would have fewer stations (23 as opposed to the 33 tram stops proposed for Luas), it would be less accessible and, therefore, fewer people would transfer to it either from private cars or other modes of transport.
City centre stations would be up to 20 metres below ground level, requiring "expensive and elaborate access arrangements", such as escalators and lifts. They would also have to be constructed at least partly by open excavation, causing disruption at street level.
"The promoters of the underground option have sought to undermine the on street LRT proposal on the basis that there would be a very significant level of disruption caused during the construction phase," it says, adding that this had never been denied by CIE.
But the EIS points out that a large number of on street LRT systems have been "successfully built into sensitive and historic urban environments worldwide" and, it says, an "effective system of project management" is being devised to minimise its impact in Dublin.
Those who favoured the underground option had also made very optimistic projections" about the number of passengers it could carry - some 12 times as many as the proposed on street LRT system. This was a "rule of thumb" calculation unrelated to actual traffic demand.
"The successful operation of an urban mass transit system requires the careful matching of supply with demand," the EIS says. Under provision would seriously undermine the attractiveness of the service while over provision would undermine its financial viability.
The predicted one way peak hour demand for the proposed on street LRT system is put at 2,800 in 2001, when it is expected to come into operation. However, this level of loading would only prevail over a short stretch from Ranelagh to St Stephen's Green.
The passenger flows projected "are well within the ability of the Dublin Luas system to cope", the EIS says. The proposed 30 metre trams would also be of modular design, permitting "relatively easy conversion" to 40 metre units at a later date as demand required.
Assuming a loading density of five passengers per sq metre and a 2.5 minute frequency, which could be accommodated within an acceptable city centre traffic management plan, "there will be a line capacity of approximately 6,500 passengers per hour per direction".
According to the EIS, this capacity figure "is well in excess of even the most optimistic projections of demand growth for the core network comprising Tallaght Cabinteely Ballymun up to the year 2011". Indeed, its reserve capacity would be over 100 per cent most of the time.
Dealing with the issue of integrating LRT with other public transport services, it says a study team has been set up to ensure that this is achieved, especially in the city centre, where some of the existing bus routes will need to be "substantially reorganised".
The EIS concedes that Luas does not include a "direct link" with the DART or other suburban railway services. But, it says, a DTI proposal to develop bus interchange facilities along Burgh Quay offered an opportunity to enhance public transport connections.
"Secondly, a number of LRT extensions have been looked at. Should additional funding become available, the LRT network could be extended eastwards via Abbey Street Lower, Busaras, Connolly Station, the IFSC and the Docklands development area to the Point Depot."
