Craigmore Viaduct Craigmore Viaduct The Craigmore Viaduct () is a railway bridge near Bessbrook, County Armagh, Northern Ireland, known locally as the 18 Arches. (OS Grid ref: Jo628). Near Newry railway station. The bridge was designed by John Benjamin Macneill, an eminent Irish civil engineer, with construction beginning in 1849 for the Dublin and Belfast Junction Railway. The bridge was formally opened in 1852. It spans the valley of Camlough River. The viaduct consists of 18 arches of 60 ft span, the highest being 126 ft, making Craigmore the tallest viaduct in Ireland. It is around a quarter of a mile long
Orthotropic deck superstructure allowed bridge launching from both ends of the Millau Viaduct. The Akashi Kaikyō Bridge's orthotropic deck allowed the Japanese to build the longest span at about , or 50% longer than the Golden Gate Bridge. Orthotropic decks permit a very shallow deck depth which reduces the steepness of approach gradients and hence their costs. The form is also widely used on bascule and other moveable bridges where significant savings in the cost of the mechanical elements can be made where a lighter deck is used. The El Ferdan Railway Bridge across the Suez Canal of Egypt is the record