Broadmeadow viaduct
The Broadmeadow viaduct, in Ireland, carries the main Dublin to Belfast railway across the Broadmeadow Estuary, about 13 kilometres north of Dublin, just north of Malahide
Malahide is a coastal suburban town, near Dublin city, located in the administrative county of Fingal, within the traditional County Dublin, Ireland. It has a village-like centre and extensive residential areas to the south, west and northwest.-Name:...

. It is approximately 180 metres (600 feet) long and it is a section of a longer crossing constructed as an embankment. The viaduct carries around ninety trains, including commuter services and heavy freight, per day and it is the sole rail route between Dublin and Belfast. It has had a history of problems with its foundations being scoured out by strong currents.


The present structure is the third on this site. The first was built in timber for the Dublin and Drogheda Railway
Dublin and Drogheda Railway
Dublin and Drogheda Railway was an Irish gauge railway company in Ireland.The D&D constructed the railway line between Dublin and Drogheda. The company presented the scheme to parliament in 1836 and received royal assent on 13 August 1836. John MacNeill was appointed as the line's engineer in...

 in 1844. Its stability was badly affected by erosion of the river bed around the piles and, after short-term remedial work, it was replaced in 1860 with a new structure of wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...

 spans on masonry piers. This sufficed until the early 1930s when new locomotives (4-4-0
Under the Whyte notation for the classification of steam locomotives, 4-4-0 represents the wheel arrangement of four leading wheels on two axles , four powered and coupled driving wheels on two axles, and no trailing wheels...

 Compounds) required strengthening of the piers and continued maintenance. Additional ballasting of the piers was also needed. The sea air caused deterioration of the wrought iron and these spans were replaced during 1966-1968 with the current prestressed concrete
Prestressed concrete
Prestressed concrete is a method for overcoming concrete's natural weakness in tension. It can be used to produce beams, floors or bridges with a longer span than is practical with ordinary reinforced concrete...

 structure. At this time, the tracks were laid on ballast
Track ballast
Track ballast forms the trackbed upon which railway sleepers or railroad ties are laid. It is packed between, below, and around the ties. It is used to facilitate drainage of water, to distribute the load from the railroad ties, and also to keep down vegetation that might interfere with the track...

, reflecting modern practice.


On Friday 21 August 2009, at 6:30pm, a 20 metre section of the viaduct collapsed. Some reports state that the collapse started while a passenger train was passing over it, others say shortly after. The Driver of the Balbriggan to Dublin Pearse service was passing over the viaduct and noticed the section crumbling away. He coasted the train (not increasing the engine revs in case the vibrations made it collapse while the DMU was on it) across it. The train was not derailed and no one was hurt: the driver raised the alarm when he arrived at Malahide. The repairs took roughly three months, with curtailment of all services north of Malahide. The competence of Iarnród Éireann
Iarnród Éireann
Iarnród Éireann is the national railway system operator of Ireland. Established on 2 February 1987, it is a subsidiary of Córas Iompair Éireann . It operates all internal intercity, commuter and freight railway services in the Republic of Ireland, and, jointly with Northern Ireland Railways, the...

's maintenance regime has been questioned and there have been previous critical reports of the viaduct's structure. Iarnród Éireann stated that the structure had been inspected three days previously. Erosion had been reported by an Irish Sea Scout
Sea Scout
Sea Scouts are members of the international Scouting movement, with a particular emphasis on water-based activities, such as kayaking, canoeing, sailing, and rowing. Depending on the country and the available water these activities are on lakes, rivers or sea in small or large ships. Sea Scouting...

 leader who later opined that a superficial inspection might have missed scour damage below water level.

Official estimates of three months to repair the viaduct (by reinforcing the seabed and replacing the collapsed pier) and restore rail services are being adhered to and Iarnród Éireann announced that the bridge would reopen on November 16 after "round the clock" repair works that reportedly cost €4 million. The bridge reopened on the scheduled date. Other piers have been strengthened and the riverbed weir restored. This is despite much more pessimistic unattributable comments by structural engineers shortly after the collapse. Such pessimism arose because the estuary is a Special Area of Conservation
Special Area of Conservation
A Special Area of Conservation is defined in the European Union's Habitats Directive , also known as the Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora...

 (SAC) and a Special Protection Area
Special Protection Area
A Special Protection Area or SPA is a designation under the European Union Directive on the Conservation of Wild Birds.Under the Directive, Member States of the European Union have a duty to safeguard the habitats of migratory birds and certain particularly threatened birds.Together with Special...

 (SPA) and it was suggested that a full environmental impact statement
Environmental impact assessment
An environmental impact assessment is an assessment of the possible positive or negative impact that a proposed project may have on the environment, together consisting of the natural, social and economic aspects....

 (EIS) would be necessary and, if a planning application were required, obtaining the necessary permissions alone could take more than three months. In addition, the stability of the remaining structure needs to be proven. A long term solution, perhaps a new longer span bridge, will be needed.

Independent Report

An independent report found that spans 4 and 5 of the viaduct began to collapse as the 18.05 Balbriggan
Balbriggan railway station
Balbriggan railway station serves Balbriggan in County Dublin. It is the northern limit of the Dublin suburban rail network and of the short hop zone.The station opened on 25 May 1844 and closed for goods traffic on 2 December 1974...

 to Pearse
Dublin Pearse railway station
Dublin Pearse, also known as Pearse Station , located on Westland Row in the Southside in Dublin, Ireland, is Ireland's busiest railway station and an important commuter terminus for the Dublin area.-Services:...

train crossed the bridge at 18.23.
The report said that staff had followed proper procedures. The design of the viaduct meant that the piers did not go down to the bedrock but instead joined with a man made causeway underneath, making the structure vulnerable to scour erosion. The causeway between piers 4 and 5 were particularly badly eroded and erosion had increased in part due to climactic, oceanographic and hydrographic factors.

Visual checks and inspections had not led to questions about the structural integrity of the viaduct.

Access to original construction drawings and historical documents was limited.

The replacement pier 4 is founded on piles and the remaining piers were retrofitted with piles.
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