It is 43 metres (141 ft) long[1] and carries a single-track line.
The original bridge was constructed in 1859, one of the few river crossings on the Belfast and County Down Railway.
It carried trains from Queen's Quay to Downpatrick and Newcastle.
After the railway was closed by the Ulster Transport Authority in 1950 (Having taken it over just two years prior), the bridge was abandoned and the girders and deck removed, through the concrete abutments and centre pier remained.
This meant reconstructing the Quoile Bridge, which was done with £110,000 1929-replica girders fabricated in Dunmurry and brought to Downpatrick by lorry.