The railway viaduct was likely constructed in c.1858, concurrent with the Rhymney Railway, as it was in place before 1860. It was likely built after the Bute East Docks (NPRN 34242) and Junction Canal (NPRN 34433), as the latter constricts awkwardly to accommodate the viaduct. The viaduct carried a tramway and then railway to the dockside coal hoists of the Bute East Dock. It was constructed of rubble stone with a brick towpath and rusticated ashlar quoins and arches. By the mid-1980s most of the arches had been walled in for storage space. It has since been demolished.

(Sources: NMW Site File Glamorganshire/Industrial/ST17NE; Turner, `The Bute Docks? in Ballenger, Cardiff: An Illustrated Guide (Cardiff: 1896), 40-54 (42))
A.N. Coward, RCAHMW, 12.07.2018