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Unread 12-03-2010, 00:23   #97
Colm Moore
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Default Erosion caused viaduct collapse

http://www.irishtimes.com/newspaper/...reaking68.html
Quote:
Erosion caused viaduct collapse

A viaduct on one of the country’s busiest railway lines collapsed because workmen carrying out safety checks did not know how to properly assess it, a report into the incident revealed today.

For more than 40 years repair work focused on pillars holding up the track over the Broadmeadow estuary, north Dublin, rather than on the causeway they were built on.

Irish Rail also said an engineer who checked the viaduct near Malahide days before its near catastrophic failure only looked at the piers and not underwater foundations being eroded.

Company spokesman Barry Kenny said significant grouting work to protect the superstructure took place in 1967 up to 2m below sea level.

But investigators warned that since then new engineers joining the company did not know there were two separate parts to the viaduct — piers resting on a causeway were not embedded in the bedrock.

Fergus O’Dowd, Fine Gael transport spokesman, accused Irish Rail of jeopardising hundreds of passengers.

“How are we supposed to have faith in the rest of the rail network, when Iarnrod Eireann’s excuse for this fiasco is that key staff members had retired?” he asked.

Tommy Broughan, Labour transport spokesman, said the investigation had uncovered astonishing gaps in maintenance work.

“The near-disastrous event raised serious question marks about the safety procedures and culture at Iarnrod Eireann and, in particular, at the Railway Safety Commission,” Mr Broughan said.

Both opposition TDs called for Irish Rail chiefs to be called before the Oireachtas Transport Committee to explain the incomplete maintenance checks.

Rail chiefs had been warned about the state of the viaduct by the Malahide Sea Scouts days before the accident on Friday August 21st last year after a canoeist saw a stone washed away.

“However a misunderstanding appears to have developed so that the engineer delegated to inspect the viaduct on 18th August was looking primarily for cracks or missing stones in the pier structure rather than in its foundations,” the investigation found.

The driver of a commuter train spotted the collapsed bridge at about 6pm and raised the alarm.

Irish Rail said the engineer sent to check the viaduct days before it fell into the sea found dressed stonework needed repointing and some cracked stones on a number of piers.

None of the faults spotted were considered serious and the engineer thought they explained the erosion warning from sea scouts.

The line remained closed for three months after the incident.

Irish Rail also denied it had been warned about serious erosion on the viaduct in 2006.

The company said specialist divers had reported the piers were subject to scouring — where water digs out a channel — and that underwater checks should be done every six years.

It claimed its own investigation after the accident uncovered the true extent of the erosion.

Safety improvements have been carried out including a bridge monitoring system on the Malahide Viaduct and piers have been retrofitted with piles in the bedrock; A bridge inspection list has been drawn up for engineers to check for scouring and underwater erosion. It is due to be complete by the end of next month.

Nine recommendations have also been put forward to improve safety on the railways.

They include flood and tidal warning arrangements, using information from Met Eireann and the Coast Guard; a “handover” process to ensure knowledge is not lost when staff move on; improved processes for dealing with information from the public; and the installation of monitoring/warning equipment to structures susceptible to scour should be extended.

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