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Gelli-Isaf Tramroad Bridge on the Abernant Tramroad is a post-medieval industrial structure protecting a route through the South Wales coalfield. Built to carry a horse-drawn tramroad across the steep terrain of the Abernant valley, the bridge reflects the transport infrastructure that developed to exploit the region's rich mineral resources. The underlying Pennine and South Wales Lower Coal Measures, which comprise mudstone, siltstone, sandstone and seams of coal and ironstone, formed the geological foundation that made this industrial activity viable from the late eighteenth century onwards.
The bridge's engineering demonstrates the practical solutions required to move coal and other minerals from collieries to processing works and distribution points across challenging topography. Its construction and survival illustrate the scale of tramway development throughout South Wales during the industrial boom period. The monument remains protected by Cadw as a significant record of the region's industrial heritage, standing as evidence of the technological innovation and infrastructure investment that characterised the coalfield economy.
Gelli-Isaf Tramroad Bridge, Abernant Tramroad is a scheduled monument protected by Cadw under reference GM411. View the official record →
Gelli-Isaf Tramroad Bridge on the Abernant Tramroad is a post-medieval industrial structure protecting a route through the South Wales coalfield. It is designated a Scheduled Ancient Monument by Cadw under reference GM411.
Gelli-Isaf Tramroad Bridge, Abernant Tramroad dates from the post medieval/modern period, and is classified as a bridge. It is one of over 32,000 scheduled monuments protected across the UK.
Gelli-Isaf Tramroad Bridge, Abernant Tramroad is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is GM411.
Several scheduled monuments lie within 10 km, including Castell Nos (4.9 km), Remains of Iron Furnace at Cwmaman (5.1 km), Garn Bica (6.1 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Gelli-Isaf Tramroad Bridge, Abernant Tramroad's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Gelli-Isaf Tramroad Bridge, Abernant Tramroad stands on Pennine Lower Coal Measures Formation And South Wales Lower Coal Measures Formation (Undifferentiated), bedrock that formed in the Westphalian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.