Cardiff in making iron and later steel, brought to the sea by packhorse from Merthyr Tydfil. This was first achieved by the construction of a long canal from Merthyr (510 feet above sea-level) to the Taff Estuary at Cardiff. Eventually the Taff Vale Railway replaced the canal barges and massive marshalling yards sprang up as new docks were developed in Cardiff – all prompted by the soaring worldwide demand for coal from the South Wales valleys. At its peak, Cardiff's port area, known as Tiger Bay, became the busiest port in the world and – for some time – the world's
Cardiff Docks area. Today, the port of Cardiff and what is now known as Cardiff Bay has been totally transformed by the Cardiff Barrage that impounds the Rivers Taff and the Ely to create a massive fresh-water lake across to Penarth Head. Only two docks, the Roath and the Queen Alexandra, remain in use, and just two shipping companies remain, albeit buoyant with their worldwide interests. Shipping movements varying from a couple of movements to 10 or 12 per tide, with trade in timber, oil, scrap and containers. Cardiff Docks Cardiff Docks is a port in southern Cardiff, Wales. At its peak,