It was officially opened in 1849, but had been completed in 1848. Being the first tubular bridge to be built, the design needed much testing on prototypes to confirm that it would be capable of carrying heavy locomotives, the testing being performed by Fairbairn. The successful result enabled the much larger Britannia bridge to be built. The current bridge has been reinforced by extra columns under the bridge into the river, but is otherwise virtually unchanged since it was built.
Since the destruction by fire of Britannia Bridge in 1970, Conwy railway bridge remains the only surviving example of this means of construction undertaken by Stephenson.
The Conwy railway bridge runs parallel to an elegant suspension bridge built by Thomas Telford, which is now in the care of the National Trust, and is open to pedestrians only. These crossings of the Conwy resemble in miniature the two greater crossings of the Menai Strait.