CONTRACTORS ON Dublin's Luas light rail system are to replace polymer track supports after defects were discovered.
The supports were supposed to have a 50 year design life but began to deteriorate seven months after the system opened.
The material is designed to provide a cushion for the tram rails and to reduce the noise and vibration of the trams.
A Luas spokeswoman said 'quality control procedures revealed that some of the bonding between the polymer material and the adjoining concrete was not performing to specification.' On a third of the track the adhesive material is failing, allowing concrete blocks surrounding the rails to come loose.
Luas was built by the AMD consortium comprising Ansaldo, MVM Rail and Ballast Nedham.
Problems with the supports are similar to those encountered by Mowlem on phase one of Manchester Metrolink (NCE 13 October 1994).
In Manchester polymer track supports on the street running sections failed under the weight of road traffic.
In Dublin, AMD was required to provide a rail system with a 50 year design life. It has agreed to fix the problem and bear the cost.
Manchester suffered huge disruption during repair of its Metrolink as many streets and sections of the tram track were closed and speed restrictions were added to much of the service.
However Ireland's Rail Procurement Agency does not expect Dublin to suffer the same fate when repair work starts later this year.