mortar. Three 12 inches (300 mm) pipes with valves ran through the lowest part of the concrete wall, allowing the water to drain to this level while excavation proceeded. The remaining water was pumped out.[19]

Gunpowder was used to loosen the marl, which was then removed by steam shovels. Various other steam-powered devices were used to remove mud, clay and rock. All the hard material was used for embankments and quay roads around the docks. The mud was placed behind these, and in trenches to seal the works from water, using special side-tipping wagons.[20]


Restored locomotive 6024 King Edward 1 crosses the Porthkerry viaduct near Barry in May 2007
Railways and docks[edit]

The docks in 1901. The west pond, later filled in, is visible to the left of the No. 1 Dock. The No. 2 Dock is to the right.
Railways totalling 27 miles (43 km) were completed before the docks opened to connect them to the coal fields. At peak, there were 88 miles (142 km) of running tracks and 108 miles (174 km) of single-track sidings, over 1,000 yards (910 m) of viaducts and 2,500 yards (2,300 m) of tunnels, with seventeen stations.[21] The lines had gentle gradients, no more than 1 in 400 against the load on the main line.[7] The main Barry railway from the docks to the coalfields joined the Rhondda Fawr line of the Taff Vale Railway near Hafod. There were branch lines that joined the Taff Vale line at Treforest and the Great Western Railway at Peterston-super-Ely and St Fagans. A branch line mainly used for passenger traffic connected Barry to the Taff Vale Railway near the Penarth dock station.[22] The railway had two long tunnels and four huge viaducts of steel and masonry. The viaducts at Llanbradach, Penyrheol, Penrhos and Walnut Tree on the line from St Fagans to Barry Junction have all been demolished.[23]

The Porthkerry viaduct was built for the Vale of Glamorgan Railway (VoGR), and still stands. The stone structure has sixteen arches and is 110 feet (34 m) at the highest point. After some construction difficulties it opened in 1900.[24] The VoGR was a branch line connecting the Barry Railway to the Great Western Railway at Bridgend.[25] A link to the Brecon and Merthyr Railway at Dyffryn Isaf in the eastern Rhymney Valley was authorised in 1898, and opened in 1905,[26] by which time the railway had been extended to 47 miles (76 km) of route.[27]

The dock layout that was originally planned was adjusted as the work progressed to ensure that the foundations rested on hard rock.[28] The basin entrance and passage were sited so that their foundations rested on hard rock. After the tide had been excluded, pits and borings were made to determine the nature of the bottom. A much narrower dock had been planned, but it was decided to move the south wall further south. A mole