Iarnród Éireann criticised over collapse of viaduct

IARNRÓD ÉIREANN’S failure to act on safety reviews stretching back to 1997 was a major factor in the collapse of the Malahide viaduct, according to the main investigation into the incident.

The report of the Railway Accident Investigation Unit (RAIU) is also critical of its parent body, the Railway Safety Commission, which it said “closed” a recommendation for a “flood/scour management plan” which had been made in separate safety reviews in 2001 and 2006.

The Railway Safety Commission closed the requirement in 2008.

The RAIU, which published its report yesterday, is an independent arm of the Railway Safety Commission, which is under the auspices of the Department of Transport.

The viaduct collapsed on August 21st, 2009, as an Iarnród Éireann passenger train crossed en route to Pearse Station from Balbriggan. The train driver reported a section of the viaduct beginning to collapse into Broadmeadow Estuary, and within minutes one of the piers holding up the track, pier number four, had collapsed leaving unsupported track hanging over the sea.

According to RAIU, an independent inspection carried out in 1997 identified that scouring had started at the base of pier four and that the rock armour weir was “too light for the job”.

A review from consultants in IRMS in 2001, and another review from consultants AD Little in 2006, both recommended the flood/scour management plan be developed.

“Scouring” is a form of erosion caused by tidal movements and flooding.

Noting the Malahide viaduct piers were formed on a “grouted rock armour weir” with stone reinforcement, the report concluded “the immediate cause” was that pier number four collapsed after the weir on which it stood was undermined “by the action of scouring”.

The report, which makes 15 new recommendations, has already been described as a “detailed and worrying account of the inadequate maintenance and inspection regime in Iarnród Éireann” by Minister for Transport Noel Dempsey.

Mr Dempsey said he had “again emphasised to the chairman of CIÉ “the importance of implementing in full the recommendations made to Iarnród Éireann”.

Blaming the scouring on a number of factors, the RAIU concluded an inspection carried out on the viaduct three days before the accident failed to identify the scouring defects which it said were visible at the time

Nor did a scour inspection undertaken in 2006 identify the viaduct as a high-risk structure to the effects of scouring.

The report also found “a historic maintenance regime for the discharge of stones along the viaduct appeared to have ceased in 1996”, resulting in the deterioration of the weir which was protecting the structure against scouring.

In its key criticism of the Railway Safety Commission, the RAIU found the commission had “closed” or dispensed with the independent consultants’ recommendations for a scour management plan.

The result was that Iarnród Éireann had not developed a flood/scour management plan at the time of the accident.

Detailing a litany of failures the report found Iarnród Éireann engineers were “not appropriately trained for inspection duties”, there was a shortfall in inspection standards and an “unrealistic requirement” for patrol gangers to carry out annual checks for scouring.

In a statement Iarnród Éireann said it accepted the findings and sincerely regretted the issues which led to this accident.

It said following the accident it began a programme “of major reform across all aspects of the safety management of infrastructure”.

“The implementation of this programme has ensured that all of the recommendations from the RAIU report and RSC audit are already actioned, with many complete.”

Fine Gael spokesman for transport Simon Coveney said Iarnród Éireann  must  immediately   implement  all safety recommendations. “The independent accident investigation unit has placed full responsibility for this accident with Iarnród Éireann.”

Railway Accident Report: Main Findings

At the time of the incident supporting piers were formed on a grouted rock armour weir, with stones intermittently placed along this weir.

The “immediate cause” of the collapse of a pier, known as pier number four, was as a result of the undermining of the weir through the tidal or flood action of “scouring”.

Contributory factors included:

An inspection carried out on the Malahide viaduct three days before the accident failed to identify the scouring defects visible at the time;

A scour inspection undertaken in 2006 failed to identify the Malahide viaduct as a high-risk structure to the effects of scouring;

Iarnród Éireann’s “likely failure” to take any action after an independent inspection carried out on the viaduct in 1997 identified that scouring had started at the base of pier four and that the rock armour weir was “too light for the job”;

The historic maintenance regime for the discharge of stones along the viaduct “appears to have ceased in 1996”.