Friday 16 May 2008

Mind the gap

The Dublin Airport Metro is in danger of repeating Luas mistakes of under-capacity, unconnected lines and incompatible track widths, writes Ruadhán Mac Eoin

€5 billion buys a lot of train, and at a projected cost of €4.88 billion, Dubliners need to get a properly integrated airport metro that should also free up key elements of the capital's existing infrastructure.

At present there are a number of "ghost" railways, which although linking heavily populated suburbs are simply not used for passenger services. Two of these routes, the Heuston to Connolly Station line under the Phoenix Park, and the Navan - Drogheda - Dublin route, have obvious potential in that one links the capital's two rail termini, while the other could half commuters journey-times traveling to Navan. The tracks are in place and little further engineering is required.

Yet although Irish Rail is progressing the Interconnector project, (which would effectively link Connolly via Docklands and Pearse to Heuston), the rail company is adamant that current congestion at Connolly makes it impossible to add in any additional services in the meantime - thus ruling out the possibility of the Navan and Heuston lines being put into service.

It is in this context that the Airport Metro must be considered. If deficiencies in existing rail infrastructure are ignored and we simply build another stand-alone project, we may get a "trendy toy" it will be a wasted opportunity in terms of filling strategic gaps in Dublin's infrastructure.

It is critical that the RPA complete the Airport Metro by linking it to the main Dublin to Belfast rail line at Donabate. Located three kilometers away from the proposed Lissenhall stop with only green fields in between, this is the obvious terminus for a project that will involve digging out half of Dublin.

Connected to Donabate, the Metro would alleviate the congested line leading into Connolly - with resulting increased capacity allowing for new services to be instated on the Heuston and Navan lines.

It is a "no-brainer". To not do so is a folly comparable to the missing gap between the Red and Green Luas lines; it is in fact the sequel - yet this time the consequences are further reaching.

Despite this, in October 2006 the RPA response to senator Tom Morrissey was that that such a link is outside their remit as it does not fall within Transport 21. This throws up serious questions as to what exactly is the RPA's brief, and if and when project deficiencies emerge, who is accountable?

The opportunity to link with the Belfast line must be reviewed. But then this requires another mind-shift by the RPA regarding their planned track width. The RPA's present plan is to build the metro at the narrower gauge of 4'8", rather than the Irish standard of 5'3" - yet if permitted, this permanently rules out the option of interconnectivity.

In terms of flaws in this project, this has to be the most strategic.It was an under-achievement to build a tramline capacity at an incompatible gauge on the former Harcourt Street railway - but at least that line is in open space should retrofitting ever be considered.

Yet with much of the Metro due to be underground, tunnel bores built according to a module of 4'8" will make it prohibitively expensive to ever recalibrate to the standard 5'3" module.

It is conceivable that a 7-inch difference on bores of this scale should not add too much to the estimated costs. However, upon enquiring to the RPA as to the reasoning, I was assured that they had "looked at it" - but that owing to prohibitive costs it was ruled out. Yet they were unable to provide me with any figures as to what the cost differences would be.

This is a disaster. Not only does the wrong width rule out options already outlined, but it also rules out the opportunity of ever revisiting oversights on the Harcourt Street Luas line. There is at present a phenomenon of city-bound Luas passengers getting on at Dundrum and first riding out to Sandyford in order to get a seat for the city-bound trip. PR spin would suggest that this is indicative of the "Luas being a victim of its own success".

I beg to differ; building at tram capacity on a segregated permanent way - and only going half the distance to the original terminus in Bray, is in my opinion a failure. Having cost twice as much as estimated, the Luas project should have delivered far more.

That the Harcourt Street Luas line is at a 4'8" gauge does not mean that the same mistake should be repeated with the metro. If the Metro is built at 5'3", it leaves open the prospect that at a later date the Harcourt Luas could be recalibrated and linked into the Dart line at Bray. Ultimately such an arrangement would yield great benefits in terms of providing two connecting parallel north-south heavy rail corridors through the city. Adding to these glitches, the RPA is also planning on a Metro capacity of only 20,000 passengers per hour - as opposed to the 30,000 capacity of a comparable metro in Munich, or the 36,000 capacity of the Dart.

Unlike the Dart, which hugs the coastline, the Metro is due to go through heavily built-up areas with population pools on both sides of the tracks; if anything its capacity should therefore be greater than the Dart. In getting the Airport Metro right, maximizing access will be critical. Of particular concern are the proposed locations of city-centre stations as an alternative routing under Marlborough Street offers a number of advantages over the mooted Parnell Square -
O'Connell Street axis.

The current plan to have the 2 stations at Abbey Street/ O'Connell Bridge and at Parnell Square does not make sense as it will disrupt O'Connell Street, while delivering two stations that are too close together - hence subverting the actual functionality of the Metro.

Rather than building these two separate stations, one well-planned station located under the Department of Education on Marlborough Street may be the better and more cost-effective option. Linked by subterranean pedestrian travelators connecting O' Connell Bridge, Busárus/ Connolly Stations, Parnell and Mountjoy Squares, such access points would significantly increase the schemes immediate hinterland. Such a model is found in many cities, from Paris to Montreal, and in Dublin the construction of three or four 500 metre-long tunnels should not be an insurmountable hurdle.

There is a joke currently doing the rounds regarding the proposed raw concrete finish in the stations interiors, to the effect "for Bertie's biggest dig-out, could they not at least get in Paddy the Plasterer?" Somewhat pertinently it sums up a general concern that for what the exchequer is about to spend, the public deserve to get more.

Ultimately unless we are to end up with a project that is over-engineered yet under-spec - in effect a stand-alone underground tram, basic but significant issues need to be faced.

Ruadhán Mac Eoin
Plan Magazine

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