A report commissioned by Iarnród Éireann reported back in March, today the Rail Accident Investigation Unit [RAIU] of the Irish Railway Safety Commission published its own report on the collapse of the Malahide Viaduct in August 2009. Some of its findings were leaked a couple of weeks ago. There are 15 safety recommendations included in the report.
The immediate cause of the collapse of Pier 4 was as a result of the undermining of the weir that surrounds and supports Pier 4 through the action of scouring. This was as a result of a combination of factors:
o An inspection carried out on the Malahide Viaduct three days before the accident did not identify the scouring defects visible at the time;
o A scour inspection undertaken in 2006 did not identify the Malahide Viaduct as a high-risk structure to the effects of scouring;
o Iarnród Éireanns likely failure to take any action after an independent inspection carried out on the Malahide Viaduct in 1997 identified that scouring had started at the base of Pier 4 and that the rock armour weir was “too light for the job”;
o The historic maintenance regime for the discharge of stones along the Malahide Viaduct appears to have ceased in 1996, resulting in the deterioration of the weir which was protecting the structure against scouring.
The above factors were necessary for the accident to happen. Contributory to the accident happening were the following factors:
o Iarnród Éireann had not developed a flood/scour management plan at the time of the accident, despite the IRMS Implementation Review (2001) and the AD Little Review (2006) recommending that this plan be developed. Contributory to Iarnród Éireann not developing this flood/scour management plan was the fact that the Railway Safety Commission closed this recommendation in 2008;
o Engineers were not appropriately trained for inspection duties, in that the inspections training course they completed was an abridged version of the intended format, and there no formal mentoring programme, for Engineers on completion of this course;
o There was a shortfall in Iarnród Éireann‟ suite of structural inspection standards in that a standard which provided guidance for inspectors in carrying out inspections was not formalised;
o There existed an unrealistic requirement for patrol gangers to carry out annual checks for scour, as they do not have access under the structure and in addition, they did not have the required specialist training/ skills to identify defects caused by scouring;
o A formal programme for Special Inspections for structures vulnerable to scour was not adopted, as per Iarnród Éireanns‟ Structural Inspections Standard, I-STR-6510, at the time of the accident.
Underlying factors to the accident were:
o There was a loss of corporate memory when former Iarnród Éireann staff left the Division, which resulted in valuable information in the relation to the historic scouring and maintenance not being available to the staff in place at the time of the accident;
o There was a dearth of information in relation to the Malahide Viaduct due to Iarnród Éireanns failure to properly introduce their information asset management system;
o Iarnród Éireanns inadequate resourcing of Engineers for structural inspections to be carried out at the Malahide Viaduct;
o Iarnród Éireanns failure to meet all the requirements of their Structural Inspections Standard, I-STR-6510, in that:
– Visual inspections were not carried out for all visible elements of structures;
– Bridge Inspection Cards, for recording findings of inspections, were not completed to standard or approved by the relevant personnel;
– A formal programme for systematic visual inspections of all elements of a structure, including hidden or submerged elements, despite an independent review recommending that Iarnród Éireann implement this programme in 2006.
Immediately after the accident, Iarnród Éireann carried out inspections on over a hundred viaducts on the network. Iarnród Éireann have now reinstating the Malahide Viaduct, ensuring that the overall structure has been significantly strengthened, that the weir profile has been restored and improved.