The Chetwynd Viaduct carried the line over a valley and the main Bandon road (now the N71) about 2 miles (3 km) southwest of Cork city. It was designed by Charles Nixon (a former pupil of I.K. Brunel) and built between 1849 and 1851 by Fox, Henderson and Co, which also built the Crystal Palace in London. It was in regular use until the line was closed in 1961, though during the dismantling of the line occasional 'recovery' trains passed over the bridge, until at least 1965.
The viaduct is 91 feet (28 m) high, has four 110 feet (34 m) spans, each span composed of four cast iron arched ribs, carried on masonry piers 20 feet (6 m) thick and 30 feet (9 m) wide. The overall span between end abutments is 500 feet (150 m).
The 100 feet (30 m) cast iron ribs were cast on site. When in situ they had transverse diagonal bracing and lattice spandrels that supported a deck of iron plates. These in turn supported the permanent way.
The structure was seriously damaged in the Irish Civil War in 1922, but was subsequently repaired. The decking was removed after closure in 1961.