The Barry Railway was an exceptionally dynamic business organisation which built up the insignificant port of Barry  within a period of some twenty years to equal Cardiff in importance as a coal exporting port. One of the routes established for coal movement was the Vale of Glamorgan Railway from Bridgend to Barry. This route called for a viaduct across the wide valley at Porthkerry.

Construction began in 1896 and what should have been a fairly straightforward process turned into a series of calamities. It started during construction when the contractors experienced problems with two of the piers, one of which had to be dismantled in order to deepen its foundations, while the other had to be underpinned.

Then within a fortnight of opening in December 1897 the embankment at the eastern end began to slip. This worsened in January 1898 together with subsidence under pier 13. Passenger trains were stopped and passengers had to walk across the viaduct. The next day it was decided that this was unsafe so a horse brake service was introduced btween Rhoose and Barry. The coal trains however had to cease altogether. Engineers suggested three possible temporary solutions while the viaduct was rendered safe:

1. Build a temporary wooden viaduct parallel to the original at a cost of £8,000.

2. A short wooden diversion from pier 9 to the east end at a cost of £4,000.

3. A diversion round the head of the valley some distance from the viaduct for £2,500.

The latter was the preferred option and a diversion of some 2.5 miles was built surprisingly quickly, by 19 April. Then the long term solution had to be found. The choice was between a permanent diversion and repairing. The latter was preferred, but more problems were encountered. In fact in a report written later that year in September, the Engineer said if he had known how many, he would have recommended building the diversion. Piers 8 and 9 had settled further due to bad workmanship. The foundations of piers 4 to 13 were being widened and underpinned as the concrete was of poor quality, more like clay, pier 8 had sunk through its foundations, all the arches were cracked, and some piers were leaning eastward by 17 ins. He recommended pulling the whole thing down and starting again at a cost of £40,000.

Cooler counsel prevailed and on 8 January 1900 the whole viaduct was reopened. It has survived into the 21st century.