SPECIALIST contractors and Iarnród Éireann-Irish Rail (IÉ) workers have completed essential coastal defence repairs on the scenic stretch of the former Dublin & South Eastern Railway line between Greystones and Bray.
The work at Bray Head saw the line temporarily closed between Bray and Greystones over the Bank Holiday weekend (October 26-28), and again on November 9-10.
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DART (Dublin Area Rapid Transit) passengers were conveyed by a rail replacement bus service between the two County Wicklow towns, with buses also linking Dublin Connolly with Rosslare.
The repairs have primarily focused on the sea defences at Bray Head, which are formed from tiered, stone-filled gabion baskets over a mass concrete wall, with a lower level masonry wall.
Erosion has resulted in the structure deforming, leading to a depression appearing in the gabion structure. This has now been reinforced with a precast concrete modular block wall, anchored in place with vertical and raker mini-piles.
Inclined drill drains were also inserted to provide for drainage of the ground water flowing through the ravine.
The original structure was left in place and the new one built around it as it was not possible to excavate because of logistical and environmental considerations. The new walls have been capped and terraced with new gabions and Reno mattresses, and any voids filled with filter bag units.
Owing to the remote and difficult location all units had to be positioned by crane; the reinforced modular blocks have a mechanical interlock that provides for temporary assembly.
The trackbed was subsequently repaired with vertical piles at close centres across the ravine over a length of 20 metres, with a geogrid installed in the ballast sub-base to support the permanent way.
IÉ spokesperson Jane Cregan told The RM: “The programme for lifting was key to the success of the project as there were more than 600 individual lifts required in the first of the two weekends and only one crane could be accommodated at this location.
“This was achieved by providing sufficient rail plant to feed the crane and the lifting/installation crew with the precast and pre-assembled units.”
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