The viaduct remains a striking piece of architecture, dominating the view from Lower Largo harbour. Built entirely in stone, it accommodated a single track railway and comprises four 60-foot arches, the deck of the river span being 60 feet above water level.
Squared rubble was used for most of the structure, however the imposts on top of the piers and voussoirs are ashlar. Below the parapet is a sloped/rounded oversail. Down pipes drain water from the deck, attached to the spandrels and piers on both elevations. Pilasters are provided at both ends whilst the western abutment also features curved wing walls. At the east end, the approach embankment is supported by triangular retaining walls, at right-angles to the railway.