The Minister for Transport, Mr Brennan, is considering plans by Iarnród Éireann for a conventional rail link between Connolly station and Dublin Airport, branching off the Maynooth line, writes Frank McDonald, Environment Editor
A detailed report, seen by The Irish Times, says the scheme could be implemented at a "comparatively low capital cost" of €900 million, relative to the metro plan, and delivered within a "relatively short time frame" of five years.
It describes Dublin Airport as "the single biggest economic unit in the country" and "one of the fastest-growing airports in the world". Passenger throughput is expected to rise from 14 million to 42 million by 2030 and job numbers from 13,000 to 26,000.
"In order to cater for this growth, a very significant investment programme will have to be undertaken at the airport, including the provision of additional terminal and runway capacities along with improved internal transport links,", the report says.
At present, private cars are the dominant method with an 80 per cent market share, giving rise to high levels of congestion on the roads leading to the airport. Different market segments include air passengers, "meeters and greeters" and employees.
Drawing on international experience, the report assumes that a rail link would attract a market share of at least 20 per cent. This could be boosted to 25 per cent or more, with a low premium fare of €5 and limits on the supply of all categories of parking at the airport.
However it says "very significant capacity constraints" throughout the suburban rail network would have to be addressed first before an airport rail link could be added, including major work on the platforms, tracks and signalling at Connolly station.
An airport spur off the Maynooth line is seen as the preferred option because it could be more readily be integrated into the suburban rail network, with a new 2 km stretch of third track between Reilly’s Crossing and Glasnevin Junction.
According to Iarnród Éireann, the proposed rail link would utilise lightly used sections of the network, including the old Midland Great Western line and the Newcomen Curve to gain access to Connolly and a new station at Spencer Dock.
On balance, the report says, a dedicated express line to the airport is more likely to attract private-sector funding in the context of a public-private partnership" (PPP), but there might also be benefits in having a number of intermediate stations on the way.
The airport spur would branch off the Maynooth line at Pelletstown, near Ashtown, where a major residential scheme is being planned. Contributions towards the cost might come from the developers here as well as at Spencer Dock and the airport.
Up to six peak-hour trains are recommended, terminating at both Connolly and the proposed new station at Spencer Dock. This would give the line a high degree of direct penetration to the city centre and the "important" southern suburbs, it says.
According to the report, which was compiled last January, one of the major selling points of a conventional rail link to Dublin Airport is that its capital cost "would be of an order of magnitude lower than that of the metro", making it more manageable and "bankable".
The construction risks would also be less due to the lack of city centre tunnelling.
However Iarnród Éireann says significant capital grants would be needed to make a PPP work.