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DART Underground (Irish: DART Faoi Thalamh),[4] previously known as the Interconnector, is a proposed mainline-rail tunnel in Dublin, Ireland. First proposed in 1972,[5] as of 2019 it is not funded or scheduled.[6][2] The National Development Plan for the period 2018-2027 proposes that a route for the proposed tunnel and line be established within that period, but does not include any funding for works or other developments.[7][6]

DART Underground
TypeRapid transit
StatusUnder review (as of early 2019)[1][2]
LocaleDublin city centre
Planned opening"After 2030"[3]
OwnerIarnród Éireann
Track gauge1,600 mm (5 ft 3 in) Irish gauge
Electrification1500 V DC Overhead catenary
Proposed route map

Clontarf Road
Dublin Pearse
St Stephen's Green
Dublin Heuston

The original plans, which propose an expansion of the electrified Dublin Area Rapid Transit (DART) network, projected the development of a tunnel between Heuston Station and Pearse Station.[8] It had been planned to leave an existing line, via the Phoenix Park Tunnel, idle in the event of the scheme being built.[9] This line however was subsequently reopened, connecting Heuston station with Dublin's Docklands - a cross-city connection which the DART Underground scheme was supposed to achieve. Accordingly, when the Irish Government published a new national spatial strategy in 2018, the revised plans dropped the DART Underground scheme in favour of these existing lines.[10][11] Having previously secured planning consent,[12] the project was initially deferred until after 2016,[13] and by 2015, it had been announced that the project would be redrafted to a lower cost design. In October 2016, a "scaled down" plan was published with a potential commencement date "in 2020".[14] As of September 2017 however, it was suggested that the developments would be deferred until after 2030,[3] with the National Transport Authority undertaking a review of the project and its route; this review projected to complete sometime between 2018 and 2027.[3][7]



DART Underground was first proposed in 1972 in the "Transportation in Dublin" study conducted by An Foras Forbartha, an anteceding body to Forfás (sometimes erroneously referred to as the 'Dublin Transportation Study') as an underground rail link to connect Dublin's three main railway stations.

In 1975 CIÉ commissioned the Dublin Rapid Rail Transportation Study[15] and which recommended a 4 Phase plan including a prototypical Dart Underground:

  • Phase 1 - Upgrade and electrify Howth – Bray (completed 1984 as the DART).
  • Phase 2 - An underground line from Connolly to Heuston. Rapid Transit tracks Heuston to Clondalkin overground. Spur to Tallaght from Clondalkin (a small part was completed in 2010 when Rapid Transit tracks were installed either side of Clondalkin).
  • Phase 3 - A short northerly spur off the Maynooth line to Blanchardstown and a short southerly spur to Broadstone. (The former was never completed but was partly revived in 2001 as Metro West before that was itself shelved in 2011 and the latter spur was opened as Luas Cross City in December 2017).
  • Phase 4 - An underground tunnel from Broadstone to Sandymount. (This was later redesigned as Metro North from Drumcondra to St Stephen's Green and shelved indefinitely in 2011).

The DRRTS, if completed as envisaged in 1975, would have resulted in a cross shaped pair of tunnels in the city centre meeting at a central station in Temple Bar.[15]

The plan was next proposed in 2001 as an 'Interconnector' in the Platform For Change strategy report issued by the now defunct Dublin Transportation Office or DTO.[16]

Platform For Change scheme published by the DTO November 2001

A Railway Order permitting the construction of the project was granted in December 2011 by An Bord Pleanála. In August 2014, Minister for Transport Paschal Donohoe TD was told that both the Dart Underground and Metro North projects would have had to rely on private funding if they were to be built. In 2010, the estimated projected cost for DART Underground was €4 billion, more than half of which was expected to be provided by a public private partnership arrangement. Mr Donohoe was told he had to decide on whether to proceed with DART Underground by 24 September 2015 when the Railway Order giving authority and planning approval expires. A High Court ruling reduced the period for which compulsory purchase order notices could be issued from seven years to 18 months.[17] The NTA's Greater Dublin Area draft Transport Strategy 2016 – 2035 published in October 2015, expressed the desire to see the tunnel completed as part of the over all DART extension programme.

Delays and statusEdit

In May 2010, Iarnród Éireann anticipated that if construction had begun in 2012 the tunnel would have been operational by 2018.[18]

On 30 June 2010, Iarnród Éireann submitted an application to An Bord Pleanála for a Railway Order for the scheme under the Transport (Railway Infrastructure) Act 2001. Under this Act, the Board charged with considering planning, environmental and property issues regarding proposed developments.

In November 2011, the government deferred funding the project due to the decrease in capital spending until 2016 at the earliest.[13][19]

A month later, in December 2011, in the Railway Order was granted for the development.[20] The granting of the Railway Order permitted both the construction of the scheme and any necessary compulsory acquisition of property. It did not however commit funding to the project.

In September 2015, it was announced that the project had been cancelled in favour of a simpler alternative. However, it was planned to return as part of a future DART Expansion Programme, starting no earlier than at least 2020 or 2021.[14][21]

As of 2016, the National Transport Authority (NTA) was reviewing the DART Underground project, with a view to examining the design of the tunnels, and undertaking feasibility studies to see if it would be possible to use single-bore tunneling as opposed to twin-bore tunneling.[citation needed]

In September 2017, it was suggested that this review would complete early in 2018, and that -depending on the outcome of the review- works on the project would not commence until at least 2020.[3] Revised projections suggested that it would be at least "2030 before passengers could use the new line".[3]

By April 2018, the Irish Independent reported that the DART underground plans had been "dropped [..] completely in favour of four new stations at ground level".[10]

In June 2018, the then Minister for Transport stated that the review of the project's plans and route (by the NTA) would complete during the period of the 2018-2027 National Development Plan.[7]


During 2010 there was opposition to the project in Dublin's East Wall area, where the tunnel would have begun and where tunnelling operations were planned to be located. Complaints were exacerbated by the suggestion that, while they would have had to endure the disturbance created by the tunneling works, East Wall residents would not gain anything from the project as they would not have easy access to a DART station - since they were roughly halfway (20 minutes walk) between the Clontarf Road and Docklands stations.[22] Complaints were also raised by residents at a Western entrance to the tunnel, at Inchicore.[23]

In late 2017, developers expressed concern that planned developments near Pearse Street Station were declined permission on the basis of their potential impact on the proposed DART Underground project.[24]

Possible routes and stationsEdit

If routed as originally proposed, the existing (single) DART line would be replaced by two DART lines forming a rough "X" shape - with an intersection at Pearse Station.

The first of these lines would begin to the north-east of the city in Howth/Malahide, follow the existing DART line to Clontarf Road station, diverge eastward into a tunnel and to a proposed underground station in the Docklands, before heading westward under Pearse Station, St Stephen's Green and Heuston Station. It would emerge from this proposed tunnel at a new overground station on the Inchicore railway works grounds, and then follow the existing South Western Commuter line to Hazelhatch to the west of the city.[citation needed]

A second line would follow the existing southern DART line from Bray/Greystones to Connolly Station, from which it would diverge on the existing but un-electrified line from Connolly to Maynooth station in Kildare, with a branch off the line at Clonsilla to M3 Parkway station in Meath.[citation needed]

If following this plan, underground platforms would be added to the existing over-ground platforms at Spencer Dock station, Pearse station, and Stephen's Green station.[25] New stations would also be built close to Christ Church (underground) and Inchicore (overground).[26][27][28]

As of 2018, no route is confirmed and no station developments are planned or funded. Additional assessment (of both routes and stations) is proposed to be undertaken between 2018 and 2027.[3][7]

See alsoEdit


  1. ^ Daniel McConnell (22 September 2015). "€3bn DART underground project scrapped in favour of scaled down version". Irish Independent. Retrieved 22 September 2015.
  2. ^ a b "Plans for Liffey bridge derailed by Dart Underground scheme". Irish Times. 4 January 2019. Retrieved 17 March 2019. The 7.6km [..DART underground..] was shelved by the Fine Gael-Labour government in 2011 [and] was not included in the 10-year National Development Plan published [in 2018..] the timeframe for the [DART underground] review is unknown
  3. ^ a b c d e f "'We won't let go': Irish Rail is convinced the long-delayed Dart Underground will go ahead". TheJournal. 21 September 2017.
  4. ^ "DART UNDERGROUND: Property Protection Scheme / DART FAOI THALAMH: Scéim Chosanta Maoine" (PDF). Irish Rail. Retrieved 5 February 2018.
  5. ^ "Could an underground Dart solve Dublin's traffic gridlock? It's being considered". The Journal. 5 February 2018. Retrieved 8 August 2018. the Dart Underground, previously known as the Interconnector [was] Originally conceived of in the 1972 Transportation in Dublin plan
  6. ^ a b "Office plan scrapped to facilitate shelved Dart Underground". Irish Times. 5 June 2018. Retrieved 8 August 2018. the [DART Underground] project having been shelved by the Government [in 2011, does] not have government funding [and] was not included in the 10-year National Development Plan published earlier [in 2018]
  7. ^ a b c d "Dáil Éireann Debate - Questions - Rail Network Expansion". Houses of the Oireachtas. 12 June 2018. Retrieved 8 August 2018. the DART Underground Tunnel - is not scheduled for delivery within the period of the [National Development Plan 2018-2027]. However, over that time [2018-2027], it is envisaged that the route for the proposed project will be established
  8. ^ Millar, Scott (23 November 2010). "DART underground line 'missing link'". Irish Examiner. Retrieved 16 September 2018.
  9. ^ Irish Rail. "DART Expansion Programme". Retrieved 16 September 2018.
  10. ^ a b "New Dart plan backs away from underground route". Independent News & Media. 24 February 2018. Retrieved 16 September 2018.
  11. ^ "Rail Network Expansion - Dáil Éireann Debate, Thursday - 29 March 2018 - Written Answers (Question to Transport)". 29 March 2018. Retrieved 16 September 2018. As outlined in the recently published 'National Development Plan 2018-2027: Project Ireland 2040' (NDP) [..] the initial sequencing of investment [..for the DART Expansion Programme..] will focus on delivery of non-underground tunnel elements of the Programme using the recently opened rail link and existing connector tunnel under the Phoenix Park
  12. ^ "'We won't let go': Irish Rail is convinced the long-delayed Dart Underground will go ahead". 17 September 2017. Retrieved 16 September 2018.
  13. ^ a b "Metro, DART projects put off in plan". RTÉ News. 10 November 2011. Archived from the original on 12 November 2011. Retrieved 10 November 2011.
  14. ^ a b "Dart Underground plan scaled down to slash costs". Irish Independent. 31 October 2016.
  15. ^ a b Environmental Impact Study Dart Underground 2010 History of Archived 7 September 2013 at the Wayback Machine
  16. ^ Platform For Change Summary Report November 2001 Archived 19 November 2007 at the Wayback Machine
  17. ^ McGee, Harry (13 August 2014). "Dublin rail projects to rely on private funding". The Irish Times. Retrieved 29 September 2014.
  18. ^ Iarnród Éireann. "About Us – DART Underground". Archived from the original on 3 March 2015. Retrieved 1 March 2015.
  19. ^ Department of Public Expenditure and Reform (November 2011). "Infrastructure and Capital Investment 2012–16: Medium Term Exchequer Framework" (PDF). Retrieved 11 January 2012.
  20. ^ "Railway Order granted for DART Underground". An Bord Pleanála. Retrieved 17 December 2011.
  21. ^ "DART Expansion Programme". Archived from the original on 12 April 2016. Retrieved 2016-10-16.
  22. ^ "Angry residents oppose DART Underground plan". Dublin People. 26 August 2010. Retrieved 23 February 2013.
  23. ^ "Opposition to Inchicore Dart plan". Irish Times. 24 February 2010. Retrieved 1 September 2018.
  24. ^ "Dart site office block decision unreasonable, says developer". The Times. 3 January 2018.
  25. ^ "Planned Projects - DART Underground". Archived from the original on 27 July 2014.
  26. ^ Agency 2014 Project Approval Application for DART Underground Phase 3 (PDF) (Report). National Transport Authority. 13 February 2014. p. 1. DART Underground consists of [..] a surface station [..] within the CIÉ Works at Inchicore
  27. ^ DART Expansion Programme Business Case (PDF) (Report). Irish Rail. 24 April 2015. p. 46. On the basis of the issues raised [in 2008] during the design review, Iarnród Éireann [instead proposed] extending DART Underground to terminate within CIÉ lands at Inchicore as opposed to Heuston Station
  28. ^ "Proposed Station at Christchurch Layout" (PDF). Archived from the original (PDF) on 20 July 2012.

External linksEdit