IT DOES not seem to make a lot of sense to spend over £200 million on a Light Rail Transit tem the capacity of which, on the basis of its promoters' own traffic estimates, appears inadequate, and the operation of which on city centre streets is likely to seriously aggravate traffic congestion, if there is to be an LRT - and the case for such a system is extremely strong - it should run underground in the city centre.
The objection to this is that running the LRT underground within the city would cost too much. It is also suggested that the cost cannot - be allowed to go outside the figure arrived at several years ago on the basis of an EU contribution of £113 million and a predetermined - sum to be provided by the Exchequer - and that it is now too late to change plans without losing the EU contribution which, it is suggested, will be payable only if the project is completed by the end of 1999.
Let me take each of these arguments in turn. First of all, no serious costing has been undertaken of an LRT system with a centre city section running underground - the estimates of tunnelling costs put forward by the exponents - of the on street system lack credibility.
Thus, in rebuttal of the proposal for an underground section of the LRT, a figure of £20 million per kilometre of LRT tunnel has been put forward by the proponents of the on street system. But the latest costing for the proposed road tunnels from Whitehall to the port, given in the recently published Environmental Impact Study for the Northern Port Access Route, is £12 million per kilometre for each 11 metre diameter tunnel.
Now each LRT tunnel would have a diameter of about 5.5 metres and thus a cross section area less than one third of that of the Northern Port Access Tunnels. Their joint cost should therefore be less than £12 million per kilometre - barely half the £20 million per kilometre figure suggested by opponents of the tunnelled system.
In Washington, 3.5 km of twin 5.4 metre diameter metro tunnels were built last year at a cost of £33 million - viz. £9.5 million per kilometre.
CLEARLY, to dismiss a centre city tunnel for the LRT on the basis that it would cost £20 million per kilometre is untenable.
Another objection to placing the LRT in a city centre tunnel is that stations would have to be excavated in crowded areas like Grafton Street. But this ignores the fact that in Vienna, for example, the tunnelling method has been used to build a station in the tunnel without excavating from above.
There are several other aspects of the tunnel alternative that also merit consideration.
First of all, the route of the on street LRT to Tallaght has to be a most roundabout one of almost 14 kilometres, going through Inchicore and along the Naas Road, with a catchment population outside the canal (within 1.5 kilometres of the track) of only 77,000. But by tunnelling along a directs line from the centre city to Harolds Cross - there is a land reservation - from Harolds Cross onwards to Tallaght which could be used for an overground route on that section - the Tallaght route could be shortened to 9.5 kilometres.
And because it would then go past Crumlin and Kimmage, the extra canal catchmeat population would thereby be increased by 30 per cent to over 100,000. The ratio of extra canal catchment population to the length of the line would thus be virtually doubled.
The traffic carried per kilometre on such a route would almost certainly be more than doubled because the transit time of such a, route between Tallaght and the city would be reduced by some 40 per cent.
There must, indeed, be some doubt about the present traffic estimates for the roundabout on street route to Tallaght because the transit time for this route is officially given as 38 minutes. But that is virtually the same as the 40-45 minutes now taken by buses between the city and Tallaght at less busy periods of the day - and not much less than the bus transit time at other periods.
Just as the placing of the Dundrum line in a 1.7 kilometre tunnel from Harcourt Street to the city centre was shown in the first of these articles to make eventually possible a virtual doubling of revenue on that line, so also a five kilometre tunnel from the city centre to a point beyond HaroldsCross would be likely from the outset to double the density of traffic per kilometre of the line to Tallaght.
THE speeding up of the service that would be made possible by using a tunnel in the city area and shortening the Tallaght route by almost one third would also make it possible to operate with a much smaller vehicle fleet and staff than would otherwise be necessary. Because the transit time would be reduced from 60 to about 30 minutes, the saving in these costs should approach one half.
In any assessment of the net additional cost of tunnelling in the city area account should be taken of the following offsetting cost reductions and social benefits:
1. The benefits that would derive from the shortening of the route by over four kilometres via Harolds Cross, e.g. reduction of track laying costs, vehicle purchase costs, and vehicle operating and staff costs.
2. The further benefits in terms of vehicle purchase and operating and staff costs arising from the much faster operation achievable on a route none of which would be on street.
3. The additional traffic that would be generated from the net increase of one third in the population served by a Harolds Cross routing.
4. The further additional traffic that would be generated by the virtual halving of the transit time.
5. The eventual social benefit that would derive from the ability of a partly tunnelled system to absorb the 50 per cent increase in traffic on the Dundrum route that would be generated by an eventual extension to Cabinteely.
6. The further social benefits that could eventually accrue from a short tunnel extension from centre city to Broadstone, which would make it possible to operate services by the former rail line to Blanchardstown, and also via Finglas and Ballymun to the air port, without traffic congesting operations on street through Drumcondra.
The argument that all these considerations should be ignored and that we should rush ahead and build what is palpably an inappropriate system, just because there are EU funds available for this project, makes no sense in either economic or social terms.
As to the argument that unless we go ahead with the present plan we would lose the EU finding the fact is that Article 5 of the relevant EU provision allows funds to be to drawn down until December 2000, and Commission sources indicate about would have no difficulty extending this by a further year.
Thus, contrary to what has been suggested here by some official sources who are anxious to discourage a reconsideration of the inadequate on street project, there remains ample time 5 1/2 years which to plan and build an economically sound and socially beneficial LRT system.
The argument that we must build the proposed on street system despite its evident inappropriateness, because if we took the time needed to reappraise it we would lose the EU money, is quite simply phoney.
It is time for the Minister and the Government to have this project re examined independently and objectively in the light of a number of important considerations that may not hitherto have been adequately brought to their attention.
