tube had been completed for traffic during April 1848. Stephenson wanted to test the structure, the first tubular crossing, to be sure it was capable of carrying the weight of a locomotive and its rolling stock. The testing was performed by Fairbairn and achieved favourable results. The bridge effectively endorsed the construction of the larger Britannia Bridge. During 1899, the tubular sections were reinforced with cast iron columns to reduce the load on the span across the river to accommodate the increasingly heavy trains being used on the route. The bridge's weight capacity had been exceeded according to a survey. The columns were fitted with inspection gantries to ease maintenance but during the 2000s they were deemed to be unnecessary and were removed. In September 1950, Conwy Tubular Bridge was recognised as being a Grade I listed structure; it is also a scheduled monument (CN167), protecting it as a historical asset for the nation. By the 21st century, the bridge is the only surviving example of a tubular bridge designed by Stephenson. The original Britannia Bridge was damaged beyond repair by fire in 1970; it was rebuilt as a two-tier truss arch bridge made of steel and concrete. The bridge is maintained by Network Rail as a part of the British railway network. Its heritage is protected and actively managed by Cadw, the historic environment organisation of the Welsh Government. See also Sharp, Roberts & Co. List of bridges in Wales References Citations Bibliography External links Aerial photo Local tourist information General description of the Britannia and Conway tubular bridges on the Chester and Holyhead Railway, 1849, from Google Book Search Bridges completed in 1848 Bridges in Conwy County Borough Buildings and structures in Conwy Tubular bridges Railway bridges in Wales Historic Civil Engineering Landmarks Grade I listed buildings in Conwy County Borough Grade I listed bridges in Wales