Initially Merthyr Tydfil was linked to Cardiff by packhorses carrying pig iron in paniers. A connecting road was built in 1767 but the great innovation was the waterway. By 1800, all the main ...

Built by engineer Adrian Stephens at the Dowlais Ironworks in Merthyr Tydfil. It was a simple safety device to warn engineers when a steam boiler was running out of water which could lead to a ...