Originally Posted by Irish Times

Serious flaws found in sections of Dublin's Luas system
By Stephen Collins, Political Correspondent

Serious flaws in sections of Dublin's Luas light rail system have been identified in a comprehensive study commissioned by the contractors who built the lines, writes Stephen Collins, Political Correspondent

Repair work on nearly eight kilometres (five miles) of track has been recommended as a matter of urgency in the interests of long-term safety for passengers using the two lines.

The study, commissioned by AMB Joint Ventures who built the Luas lines, was carried out by the Institute for Railway Engineering at the University of Graz in Austria.

It identifies deficiencies in the bonding material under the rail in the city sections of both Luas lines. Approximately 6.4km of track on the Tallaght line and 1.3km on the Sandyford line are affected.

"The debonding is gradually more serious with sharper curvatures of the alignment and manifests itself by opening of fissures and cracks which permit penetration of water into the load-carrying system," according to the report.

It says that, so far, no reduction in operational safety had been observed, but concern was expressed about the future. "The development of bonding deficiencies gives rise to foresee a growing uncertainty towards the reliability and proper functioning of the system, particularly in tight curves."

The report says that even before the opening of the Luas lines, the tracks were beginning to show deficiencies. "After installation, a small number of blocks showed debonding, with frequent use by trams the number of affected blocks increased dramatically.

"After a short period of commercial tram operation (October 2004) already 32 per cent of blocks in straights and wide curves and 57 per cent of blocks in tight curves showed failures," says the report.

The report recommends that the track structure will have to be strengthened in the critical sections through a number of track-stiffening measures.

Fine Gael MEP Gay Mitchell, who has raised safety concerns about the system in the past, said yesterday that the report raised a number of issues.

"Firstly we need to know why this report was commissioned and what its cost was. We then need to know what the cost is going to be of putting right the deficiencies that have been identified so soon after the system was opened. Finally, we need to know what the safety implications are."

Originally Posted by Irish Times

Track problems down the line for Luas
By Stephen Collins, Political Correspondent
A report has urged repairs to Dublin's Luas lines, writes Stephen Collins, Political Correspondent

Repair work on both of Dublin's Luas lines has been recommended in a draft report submitted last month to the contractor who built the lines.

The report was commissioned by AMB Joint Venture because of concerns about the safety and durability of the track in the sections that run through city streets.

The report was carried out by Prof Klaus Riessberger and Dr Albert Jorg at the Institute for Railway Engineering and Transport Economy at Graz University of Technology in Austria.

The experts concluded that sections of the track showed deficiencies with respect to the bonding between the concrete tray under the rail and the rail support system.

"The Edilon-track of the new Luas light rail system with individual supports in Dublin, Ireland, shows deficiencies with respect to bonding between concrete rail block and/or concrete tray and the intermediate elastic material Corkelast M.

"The debonding is gradually more serious with sharper curvatures of the alignment and manifests itself by opening of fissures and cracks which permit penetration of water into the load carrying system," it says.

The Corkelast material is responsible for the elasticity of the rail supporting system. It is made up of two components which are mixed in an automatic mixing unit.

The report points out that the Edilon embedded block system is well proven, and is used in the Madrid metro and Bilbao as well as in Dublin.

The preface says that an investigation of the causes of the damage was not the main aim of the study, and it does not draw firm conclusions as to why the bonding has deteriorated so quickly.

The authors of the report do come to conclusions about how the problem can be dealt with.

For a start they rule out rebonding by insertion of gluing material. This, they say, is not a reliable option.

"Protection of the surface of the Corkelast M material from water penetration is highly advisable.

"The seriousness of the deficiencies grows with reduction of radii. It is concluded that different methods of improvement should be applied to cater for those different conditions.

"In the very sharp curves the Edilon design is highly overstressed, particularly by the rotation of the rail under horizontal forces. This is a result of the independent bearing of the rails which are not ready to take the high spreading forces in the sharp curves and which in turn results in very high lateral forces in the rail blocks and over-stressing the concrete Corkelast interface."

A number of laboratory tests were conducted in Graz to establish reliable methods of repair. While they have still not been fully completed, a number of provisional recommendations are made.

The first is that the open surfaces of the Corkelast material, surrounding the rail blocks, should be protected against water penetration with an easy to apply permanent elastic coating.

The next recommendation is that overstressed Corkelast M fillings should be replaced with rubber "shoes". These are available and a prototype has been made by Semperit.

The report suggests that the sharp curves should be counteracted by an alteration of the load transmission. "Track panels, where the two rails are stiffly interconnected by cross-bars, transmit only the difference of the individual horizontal forces into the sub-base and additionally counteract rail rotation. To this end it is advised to strengthen the track in these critical sections by considerably stiff connections between the two rails."

The report says even before the lines were opened deficiencies had begun to show up.

"On straights and in wide curves the debonding mainly occurs on the long sides of the blocks; in tight curves debonding is noticed on the short sides. Also, in transitions between traditional track and other track systems debonding appears."

It adds that after installation a small number of blocks showed debonding but with frequent use by trams the number of affected blocks increased dramatically.

"So far no observation was made which indicates any reduction in operational safety. Nevertheless, the development of bonding deficiencies gives rise to foresee a growing uncertainty towards the reliability and proper functioning of the system, particularly in tight curves."

The report says that cracks will develop as a result of debonding, and these will allow water to flow into the gaps.

"Therefore it is strictly recommended to protect the working system from water in order to achieve the desired durability of the entire system."

While the report came to no definitive conclusions about the reasons for the debonding, one of the findings was that batches of non-fully cured Corkelast M material was used. "Most likely either the chemical composition was incorrect or the mixing of the two components imperfect."

Originally Posted by RTE Online

LUAS design & construction questioned
05 January 2006 15:37

One of Ireland's leading civil engineering experts has questioned the design and construction of the LUAS system in Dublin after an engineering study identified serious flaws in sections of the light rail system.

Eugene O'Brien, Professor of Civil Engineering at UCD, said a number of issues were raised in the report.

An engineering study commissioned by AMB Joint Ventures, the company which built the LUAS, found flaws in the system and said repair work on sections of the track is needed.

The study was carried out by the Institute for Railway Engineering at the University of Graz in Austria.

However, the State body with responsibility for the system, the Railway Procurement Agency, has said it does not accept the wrong design was used for the system.

The Director of LUAS at the RPA, Michael Sheedy, acknowledged that some materials had not performed as anticipated.

The RPA said repair work on both LUAS lines is due to commence in the next few months and the cost of the repairs will be borne by the contractor who built the lines.

The agency says the areas identified by the study are at the outer reaches of both LUAS lines rather than in the city centre as has been reported.

The Department of Transport said there would be minimum disruption to passengers.

Originally Posted by ireland.com

RPA says Luas flaws not a threat to safety
By ireland.com reporter

Last updated: 05-01-06, 12:26

Operators of Dublin's Luas system today insisted that flaws found on suburban sections of track are not an immediate risk to public safety and repair work is not urgent.

An engineering study commissioned by the system's builders, AMB Joint Ventures, found that nearly five miles of both the Red and Green Line had deficiencies in the underlying bonding material.

The polymer/cork substance is designed to reduce noise and vibration at certain sections of track. But particularly where the tracks turn around bends the bonding is separating leading to cracks allowing water in.

"The debonding is gradually more serious with sharper curvatures of the alignment and manifests itself by opening of fissures and cracks which permit penetration of water into the load carrying system," the report says.

Safety is not yet affected but it warns that left untreated "reliability and proper functioning of the system" would be "uncertain".

The report recommends a number of measures be taken to strengthen the track structure and the Rail Procurement Agency said today the repairs would be carried out shortly and should not affect services.

RPA spokesman Ger Hannon said the flaws were only present on accessible suburban sections of track and not at city centre locations. The affected sections are mounted on concrete slabs and attached by metal clips, such as along the Grand Canal on Davitt Road.

When the work is completed, AMB will be able to guarantee the lines for up to 50 years with minimal maintenance.

"We can carry out the work over the next few months and it should take place over several weeks depending on the level of resources we apply to it," Mr Hannon said.

"We need to know that this work will last 50 years. The work should not involve disruption and passengers shouldn't know that it's going on.

"It will be carried out at no extra cost to the Exchequer."

The engineering study was carried out by the Institute for Railway Engineering at the University of Graz in Austria.

Additional reporting PA

Originally Posted by RTE Interactive

RPA happy with LUAS design

05 January 2006 17:01
The state body responsible for Dublin's LUAS tram system, the Railway Procurement Agency, has said it is happy with the design used for the light railway, despite an engineering study that identified serious flaws in sections of the track.


The RPA was responding to comments by one of the country's leading civil engineering experts who today questioned the design and construction of the Luas lines.

Eugene O'Brien, Professor of Civil Engineering at UCD, said a number of issues were raised in the report.

The engineering study commissioned by AMB Joint Ventures, the company which built the LUAS, found flaws in the system and said repair work on sections of the track is needed.

The study was carried out by the Institute for Railway Engineering at the University of Graz in Austria.

The Director of LUAS at the RPA, Michael Sheedy, acknowledged that some materials had not performed as anticipated.

The RPA said repair work on both LUAS lines is due to commence in the next few months and the cost of the repairs will be borne by the contractor who built the lines.

Originally Posted by Mark Gleeson

Second is the slab track solution http://www1.tdclighthouse.com/edilon...D=1144&l=1&c=2

Originally Posted by philip

It makes sense that the red line is affected to a far greater degree when you realise that all the off street stetches are layed as in the above link, very few bits of the green line (I'm thinking just over the Dargan and Charlemont bridges reall) are layed thus.

Originally Posted by Derek Wheeler

There are no more curves on the block structure after this

Originally Posted by Derek Wheeler

Suir Bridge could be similar to Dargan bridge. Mark?

Originally Posted by Derek Wheeler

As for james's hospital, there's grass between the rails on the curve from fatima into the hospital grounds. Cant see whats under it as it was landscaped as part of the build.

Anyone?

Originally Posted by Mark Gleeson

Thats the onstreet type the rail is encased in concrete so its not on blocks