Interconnector (rail tunnel)

network, and connect these rail transport systems.

It is intended to provide a link between the planned Docklands railway station at Spencer Dock (northern rail and western/north-western railway lines), Pearse Station (southern railway line) and Heuston Station (southwestern railway line). In addition, it will connect to the Luas light rail system, and the planned Metro.

Background

Dublin's current mass transit projects do not allow for easy transfers. The existing Luas light rail lines, electrified DART and commuter trains do not connect with each other adequately and to address this an integrated transport plan, Transport 21, has been announced.

The interconnector itself is a critical component for successful transport integration, as it will connect with the existing and proposed Luas system, and the planned Metro system.

Its primary purpose is to address the capacity issues on the existing rail lines, stemming from the fact that Connolly station is the terminus for almost all of Dublin commuter rail traffic. The tunnel will take much of the pressure off Connolly and allow Iarnród Éireann to cope with the anticipated demand, which would not be possible otherwise [http://www.iei.ie/uploads/Files/SectorPapers/25/%7BB6E13A575C5F4D17AEC487F477A476C4%7D_IEI%20R%20%20T%20%20IRISH%20RAIL%20INTEGRATED%20PLAN%2017%20NOV%2004.PDF] .

It also addresses the issue that south-western commuter services do not terminate in the city centre, but rather at Heuston, and this is regarded as unattractive for many commuters.

One alternative solution that has been advocated is running these services through the existing Phoenix Park tunnel to the new temporary station at Spencer Dock; however, this proposal has not been adopted and does not appear to be on the agenda. This proposal would not increase capacity but would make commuting more attractive to those along the Kildare line.

pecifics of the plan

Dublin's existing DART line runs north to south directly through Dublin city centre, and must share limited track with inter city rail services and long distance commuter rail service. The city centre -- in particular, the two-track elevated "Loop Line" bridge over the Liffey between Connolly Station and Pearse Station -- has limited capacity and so cannot accommodate many extra train movements during peak hours.

By diverting the DART line from the north to Dublin's new Docklands developments and thence under the city, through the Interconnector / DART Underground, to Dublin's westerly Heuston Station, much more capacity for DART can be provided. The DART line will then proceed to Dublin's westerly suburbs, replacing some existing commuter services with much more frequent electric DART trains that will connect directly with the city centre.

Meanwhile DART trains from the south will continue along the existing track through the city centre, connecting with the Heuston-bound DART line (underground in the Interconnector) at Pearse Station. After Connolly station, they would head to the north west to provide an electrified DART service to Maynooth, Co. Kildare; and to Dunboyne, Co. Meath along a re-opened Navan-Clonsilla rail line.

Benefits

The new scheme will provide two separate DART lines, each connected with various pieces of Dublin's existing and planned transport infrastructure. Capacity will be greatly expanded and allow for more frequent DART journeys and greater use of public transport. This would have the effect of reducing traffic congestion, commuter frustration, and providing a reliable alternative to the car in the city.

Primary stations on routes

DART Line A
* Balbriggan
* Malahide* / Howth*
* Docklands
* Dublin Pearse*
* Stephen's Green
* Christchurch
* Dublin Heuston
* Hazelhatch
* Sallins

DART Line B
* Bray* / Greystones*
* Dublin Pearse*
* Dublin Connolly*
* Drumcondra
* Clonsilla
* Maynooth / Dunboyne

"* denotes stations which currently have DART services"

Time frame

Iarnród Éireann have recently placed tenders seeking engineers to begin advanced planning of the project. Expertise learned from tunnelling with the Dublin Port Tunnel will help with the project, and hopefully help to bring completion of the project on time (roughly 2015).

As construction has not yet started, there have not been any definite dates given, but Irish Rail are hoping that construction will begin in 2010 and that the Interconnector / DART Underground will be open by 2015.

Additional information

The Interconnector / DART Underground joins several major revamps of the Greater Dublin rail infrastructure.

* The mainline from the southwest gains two new tracks under the Kildare Route Project. On arrival at Inchicore/Heuston a tunnel skirts the south bank of the River Liffey, with a link at St. Stephen's Green with the LUAS lines to Tallaght (via a proposed extension to connect the two existing lines) and Sandyford (currently being extended to Cherrywood}, as well as the planned Metro North line link to Swords.

* The tunnel continues on to intercept Pearse Station, connecting with DART services south to Greystones and mainline services to Rosslare.

* The tunnel, but not the line, terminates at Spencer Dock Station, which when constructed will supplement Connolly Station, a short distance west on the proposed LUAS Line C1. It is intended that the track from Hazelhatch will be electrified and thus that Malahide-bound DART services will relocate from Connolly to Spencer Dock. The Malahide electrified line would be electrified to Balbriggan and DART service extended there. Previous proposals to extend electrification further, to Drogheda and Kildare, have been dropped in the Transport 21 plan, but it is possible they will proceed at some point in the future.

* The Maynooth/Dunboyne line will be electrified under this plan and services from Greystones will terminate there via Pearse and Connolly Stations, the latter remaining the final destination of Belfast mainline service. It was also announced, seemingly incorrectly, that electrification was to be extended to Navan in the plan, however this appears to have been dropped.

The current re-signalling of the Dublin Area network (the DASH project stages 1 and 2) is critical to the plan as it allows higher throughput of trains per hour. However this alone will not allow the project to proceed as the "Loop Line" bridge and Connolly Station's platforms cannot cope with the number of planned services.

On May 11 2006, Iarnród Éireann officially announced the start of the project. [http://www.irishrail.ie/news_centre/news.asp?action=view&news_id=78]

On June 28th 2007, Iarnród Éireann announced public consultation days, along with information on the tunnel, and the alignments of the tunnel and the stations along it. [http://www.irishrail.ie/projects/dart_underground.asp]

ee also

* Transport 21
* Rail transport in Ireland
* Dublin Area Rapid Transit

External links

* [http://www.meathontrack.com/navandroghedarailway.html Photo Survey of Navan's existing railway line that could benefit from extra capacity generated by the Interconnector]
* [http://www.platform11.org/transport21 Platform 11 Transport 21 information]
* [http://www.irishrail.ie/projects/dart_underground.asp Irish Rail information on the project]