The story of Tassagh Viaduct
Tassagh Viaduct was completed in 1910 to carry the Castleblayney, Keady and Armagh Railway across the Callan River valley. It is credited to the engineer Sir Benjamin Baker, better known for his work on the Forth Bridge. The structure runs 174 metres on 11 brick arches set on concrete piers, reaching 24 metres at its tallest, and the arches and vaulting are brick while the piers are concrete.
The line it served had a short and unlucky life. The Armagh to Keady section opened in 1909, and the route was soon taken over by the Great Northern Railway of Ireland. Partition in 1922 brought customs inspections that made the cross-border traffic uneconomic, and services beyond Keady to Castleblayney ended by 1924.
From 1932 only goods trains worked the remaining stretch to Keady, and the line closed completely in 1957. The viaduct had carried trains for fewer than 50 years, and for much of that time only freight. The rails were lifted and the route fell silent.
In December 1976 Tassagh Viaduct was made a Grade B listed building, recognising it as a notable piece of early 20th-century railway engineering. Ownership rests with Translink, under the Northern Ireland Transport Holding Company, and the viaduct survives intact above the river with the old Tassagh Beetling Mill in its shadow.