Iarnród Éireann, with the support of Transport Infrastructure Ireland, are carrying out the work which begun on Wednesday, 22 February.
The Pill Road (N24) at Carrick-on-Suir is now closed until 8am on Monday, 27 February.
Currently, the bridge is a traditional beam and steel troughing construct which was built in 1931. It was fitted with collision protection beams in 2007 to prevent structural damage, however this bridge has been struck 41 times since 2009 making it the most struck rail bridge in the country. The current clearance height is 4.54 metres and this will increase to 5.03 metres with the installation of the new bridge.
The new structure was designed by the Iarnród Éireann Structural Department assisted by the design and production teams in concrete specialists Shay Murtagh Precast. It will have a reinforced concrete deck with an embedded rail system to reduce the construction height. the rail embedment system allows the rail to sit in a designed rail holder supported by specialist cork elastic material which sits directly on the deck. This reduces the depth by half a metre as opposed to a conventional railway sleeper with ballast. The track will be raised over 150metres on the approach to the bridge to facilitate the increased clearance.
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The bridge will be lifted in one movement over the weekend using a 500-tonne crane.
Train services will be substituted with a bus transfer between Limerick Junction and Waterford until Saturday, 04 March to facilitate the works.
Stephen Bateson, Principal Engineer, Structures, Iarnród Éireann said: "The key element of this design was to include an embedded rail, which in combination with the new concrete deck, gives as low a depth from the top of the rail track to the underside of the bridge as possible. This innovative solution however requires more precision in design and installation than conventional ballasted track."
Robert Fitzsimons, Design Manager, Shay Murtagh Precast said: "The total duration of the project including the detailed design, structure manufacture, factory trial assembly and transportation to site was just 10 weeks in total. As with all bridge replacements that are carried out there are unique set of challenges to each individual structure, but due to the good working relationship between the teams at Iarnród Éireann and Shay Murtagh Precast the challenges were identified and solutions found seamlessly."
(CD/LM)
