DART+ DART+ South West Emerging Preferred Option
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DART+ South West Emerging Preferred Option

The preliminary options assessment studies have led to the identification of the Emerging Preferred Options for each of element of the project.

The project has been divided into sections describing the project in a east west direction, as follows:

General Linear Works

The Project will require modernisation and modifications to the existing railway line. 

There is a range of general linear works required along the full length of the Project to enable the electrification of the line and the upgrade of the existing network. These are:

  • Overhead electrification equipment (OHLE) will be required along the full extent of the railway line from Hazelhatch & Celbridge Station to Heuston Station and through the Phoenix Park Tunnel Branch Line up to Glasnevin Junction, where it will link with the proposed DART+ West Project. This will be similar to the OHLE currently used on the existing DART network. 
  • A number of electrical substations will be required at intervals along the rail line to provide power to the network. 
  • Signalling upgrades and additional signalling will be required to the upgraded infrastructure. 
  • Where existing bridges do not provide the necessary height for overhead electrification of the lines or width for four tracking, options are being considered on a case-by-case basis, these include: 
    • Provision of specialist electrical solutions for the OHLE with reduced clearance;
    • Lowering the rail track under the bridge; 
    • Modification of the existing structure; 
    • Removal of the existing structure and provision of a replacement structure; or 
    • A combination of the above.
  • Overhead electrified line protection works will be required at all existing rail overbridges.
  • Interfaces with existing utilities, boundary treatments (including new retaining walls), drainage works, vegetation management and other ancillary works will be required along the length of the project.  

Hazelhatch & Celbridge Station to Park West & Cherry Orchard Station

The works carried out under the original Kildare Route Project between 2006 and 2009 provided the main groundwork for DART+ South West including the existing four track system and several reconstructed bridges. 

The Emerging Preferred Option for this circa 11km section comprises the general linear works as outlined above. The electrification works can be run under the existing bridges with no / minimal intervention in the bridge structures and minor localised track lowering works and use of specialist OHLE solutions to achieve the required clearance. 

All these works can be accommodated within the existing rail corridor.

Existing Four Track System

Park West & Cherry Orchard Station to Heuston Station

The section between Park West & Cherry Orchard Station and Heuston Station requires electrification and widening to four tracks. To meet these project requirements, the track corridor must be widened, and the physical surroundings must be altered. Extending to four tracks in this area will require an increase in the width of the existing rail corridor outside of lands owned by Iarnród Éireann, potentially interfering with property rights (on a permanent and / or temporary basis). Following an option selection process that included developing and evaluating a number of options at each location, the Emerging Preferred Option for each location was established. These are described below.

Area around Le Fanu Road Bridge

The rail corridor on the Cork Mainline between Cherry Orchard Footbridge and Le Fanu Road Bridge currently comprises three existing tracks and at Le Fanu Road Bridge narrows to two existing tracks. Increasing to four tracks requires the realignment of the existing tracks and an increase in the overall railway corridor width. Le Fanu Road Bridge is a narrow arch structure and is inadequate in both span length and height for the four tracks and electrification infrastructure. 

The Emerging Preferred Option replaces the bridge with a longer span or spans to facilitate the additional width required for the additional tracks. To overcome the lack of height available for the electrification infrastructure, the road level will be raised in combination with lowering the rail track. Retaining walls are required to the north and south of the corridor adjacent to the new bridge to allow the widening of the corridor while minimising the impact on the adjacent properties. The raising of the road level will also mean that retaining walls will be required along the road to the north of the railway. 

The proposed replacement bridge will be a modern structure that will provide segregation for pedestrians, cyclists and improved sightlines and will be a significant improvement on the existing situation for all road users. 

The proposed new bridge is presented below in sectional elevation looking east.

Emerging Preferred Option for Le Fanu Road Bridge (Click Image to Enlarge)

Click here to view an accessible version of the Emerging Preferred Option for the Le Fanu Road Bridge.

Area around Kylemore Road Bridge 

This section of the railway comprises two existing tracks and one bridge structure (Kylemore Road Bridge). The bridge does not have adequate span length to fit four tracks and is not high enough for the DART line electrification infrastructure to pass under. There are a number of constraints in this area including:

  • The railway corridor is bounded on both sides by soil slopes. 
  • To the north and south of the bridge are road junctions and access points that that significantly restrict alterations that may be required to the road geometry.
  • Kylemore Road is a potential route for a future LUAS line. Therefore, the design must consider this potential new infrastructure.
  • The west of Kylemore Road Bridge has been identified for a potential future railway station to the west of the bridge. The designs for this area must not prejudice its delivery in the future. 

The Emerging Preferred Option for Kylemore Road Bridge replaces the bridge with a longer span to facilitate the additional track width. To overcome the lack of height available for the electrification infrastructure, the road level will be raised in combination with lowering the rail track. 

Retaining walls are required to the north and south of the corridor to allow the widening of the corridor while minimising the impact on the adjacent properties. The raising of the road level will also mean that retaining walls will be required along the road to the north and south of the railway. 

The proposed new bridge is presented below in sectional elevation looking east.

Emerging Preferred Option for the Kylemore Road Bridge (Click Image to Enlarge)

Click here to view an accessible version of the Emerging Preferred Option for the Kylemore Road Bridge.

Area around Inchicore Works

The railway in this area (between Kylemore Road Bridge and Sarsfield Road Bridge) comprises two mainline tracks which are joined by two additional short tracks (or sidings) connected to the Inchicore Depot. The existing tracks through the area would not provide the required four tracking while maintaining the functionality of the depot. Therefore, the laying of additional tracks is required, which in turn requires the realignment of the existing tracks and an increase in the railway corridor width in this area. 

The Emerging Preferred Option focuses this enhancement of the corridor to the south requiring the demolition / modification of some Iarnród Éireann facilities within the Inchicore Depot. There is potential interference to third party property rights but further design development and technical and construction related solutions will seek to minimise this. 

Khyber Pass Footbridge

Khyber Pass Footbridge is an existing pedestrian overbridge linking Inchicore Works to Sarsfield Road to the north. The existing structure has three tracks beneath it and is not wide enough to safely accommodate an increase to four tracks. 

The Emerging Preferred Option provides a new pedestrian bridge with sufficient height and width to meet the requirements for four-tracking and electrification. The extent of works may potentially interfere with property rights in the immediate area but further design development and technical and construction related solutions will seek to minimise this. 

The proposed new pedestrian bridge is presented below in sectional elevation looking east towards Heuston Station.

Emerging Preferred Option for Khyber Pass Footbridge (Click Image to Enlarge)

Click here to view an accessible version of the Emerging Preferred Option for Khyber Pass Footbridge.

Sarsfield Road Bridge Area

Sarsfield Road Bridge carries the railway over Sarsfield Road. Both the bridge and the railway corridor in this area comprise three mainline tracks and are not wide enough to carry the fourth track that is required. 

The Emerging Preferred Option replaces the existing bridge deck with two parallel bridge decks, one for the Intercity service and one for the DART service. The existing walls along Sarsfield Road would be mostly left untouched by the construction works. 

The proposed bridge is presented below in sectional elevation looking east towards Heuston Station. There is potential interference to third party property rights but further design development and technical and construction related solutions will seek to minimise this.  

Heading east of the bridge the corridor will predominantly be widened to the north to add a fourth track (into the embankment between the railway and Con Colbert Road).

Emerging Preferred Option for Sarsfield Road Bridge (Click Image to Enlarge)

Click here to view an accessible version of the Emerging Preferred Option for Sarsfield Road Bridge

Area around Memorial Road Bridge

The existing Memorial Road Bridge is too short in span length to accommodate the additional fourth track, so a longer span bridge is required. The existing bridge also does not have the height required to accommodate the electrification infrastructure beneath the bridge. The bridge is very close to the Con Colbert dual carriageway so any increases in the height of the road would have an impact on the dual carriageway.  

The Emerging Preferred Option replaces the bridge with a longer span bridge. In addition, the rail tracks will be lowered to facilitate the electrification infrastructure beneath the new bridge. The masonry retaining walls on the southern side would need to be strengthened due to the lowering of the track and new retaining walls would be required along the northern side. 

The permanent way boundary wall along Con Colbert Road will need to be reconstructed to a higher containment standard and height, as it will be removed to provide retaining wall construction access. 

The proposed bridge is presented below in sectional elevation looking east towards Heuston Station.

Emerging Preferred Option for Memorial Road Bridge (Click Image to Enlarge)

Click here to view an accessible version of the Emerging Preferred Option for Memorial Road Bridge.

South Circular Road Junction Area

This area extends from Memorial Road Bridge to the South Circular Road Junction. There are two major bridge structures in this area which are part of the junction namely South Circular Road and St. John’s Road Bridge. St. John’s Road Bridge has an adequate span length to enable a layout with the minimum four tracks requirement and is high enough for the electrification infrastructure required for DART. South Circular Road Bridge does not have adequate span length to fit four tracks and is not high enough for the electrification infrastructure to pass under. 

The Emerging Preferred Option leaves South Circular Road Bridge in place and includes the construction of a new structure to the north of the existing bridge. The new structure would be for the new DART tracks and the existing Intercity service would continue under the existing South Circular Road Bridge. The new structure requires retaining walls to be constructed on both sides beyond the junction area to the west. 

The South Circular Road Junction is extremely busy and frequently has traffic queues, so any works in this area are likely to impact traffic. In order to minimise impact on traffic during the works, the construction will be carried out in phases, utilising all available road space to safely divert all road users around the affected area. 

The new structure will accommodate DART trains. This means that the existing South Circular Road Bridge would not need to be electrified and the track levels can be left as they are currently. 

The proposed intervention is presented below in sectional elevation looking east towards Heuston Station. In addition, an aerial view of the Emerging Preferred Option for the South Circular Road Junction is also presented below.

Emerging Preferred Option for South Circular Road Bridge (Click Image to Enlarge)

Aerial View of Emerging Preferred Option for South Circular Road Junction (Click Image to Enlarge)

Click here to view an accessible version of the Emerging Preferred Option for South Circular Road Junction

Heuston Station and Yard

Heuston Station currently does not have any provisions for electrification. Platforms and sidings within the Heuston area are to be electrified to receive the DART+ Fleet. These works will require re-arrangement to provide access to the new DART platforms and to update access to inter-city tracks. 

In terms of permanent way works, the constraints on track work in Heuston Station are predominantly those posed by the need to maintain the operational capability. 

In the station area, platforms and sidings will be electrified as required for the DART services.  

All works can be undertaken within land owned by Iarnród Éireann.

Heuston West Station to Glasnevin Junction

This area extends from the east of St John’s Road Bridge and northwards over the River Liffey via the Liffey Bridge and under Conyngham Road Overbridge where it enters the Phoenix Park Tunnel.  

Close to the junction of the Cabra Road and Navan Road the line exits the Phoenix Park Tunnel and continues north under several road bridges as follows: McKee Barracks Bridge, Blackhorse Avenue Bridge, Old Cabra Road Bridge, Cabra Road Bridge, Fassaugh Road Bridge, Royal Canal and LUAS Twin Arch, the Maynooth Line Twin Arch and Glasnevin Cemetery Road Bridge. The line then continues east and interfaces with the proposed DART+ West Project at Glasnevin Junction. 

A requirement of the DART+ South West Project is to investigate the feasibility of a new station at Heuston West, at the site of the existing Platform 10, located to the north west of the greater Heuston Station complex adjacent to the Liffey Bridge. A preliminary assessment for the station has been undertaken by the project team and concept design options are being considered. 

The Emerging Preferred Option for Liffey Bridge features electrification and retention of the existing fixed track system. 

The existing twin tracks along the Phoenix Park Tunnel Branch Line will be electrified. DART+ South West is currently undertaking surveys and analysis along this section, including within the tunnel, to understand the current characteristics and constraints. 

The Emerging Preferred Option will follow the existing rail corridor and may involve track lowering and/or bridge modifications at certain locations to achieve the height requirements for electrification. 

The specific interventions at each bridge along this rail section will be based on the analysis of survey data and presented at Public Consultation No. 2.

Northern and Southern Portals to the Phoenix Park Tunnel and view of inside tunnel (Click Image to Enlarge)

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