Authorised share capital was £1,050,000, to build from Barry northward to a junction with the Taff Vale Railway at Trehafod, in the Rhondda; there was to be a south-to-west junction with the GWR main line (former South Wales Railway main line) at Peterston and an east to north connection nearby, and a spur to join the Taff Vale main line at Treforest. The dock was to be 73 acres in extent, the largest enclosed dock area in the country; in fact the area between Barry Island and the mainland was to be made non-tidal, an area extending to 200 acres.