The Rumney Railway was originally an industrial tramway built to ship goods to and from the west side of the Ebbw Vale to Newport Docks.
Built from 1826 and later converted to a standard gauge railway, it was eventually subsumed by the London and North Western Railway as part of its Brecon and Merthyr Railway system to compete with the GWR in extracting coal from the South Wales coalfield.
Having given permission to the Monmouthshire Canal company to build an industrial tramway to Alexandra Docks, Newport Corporation was lobbied by the Chamber of Commerce and decided that the line needed additional competition. It therefore agreed to allow construction and access to two more tramways - the Sirhowy Railway and the Rumney Railway.
The Rumney Railway was thus built as an industrial tramway, from Newport to Machen, where it established its main operating base and railway works. As the Glamorganshire Canal and others already had rights to construct tramways to service the coalfields towards Caerphilly, the Rumney was forced to take the steeper route via Bedwas into the Rhymney Valley, for access to Dowlais and the iron works there.
As the South Wales Railway was driven through by Brunel, the Rumney was in need of vital investment and improvement, and so allowed the LNWR to take shares in return for engineering expertise, with the option of a later purchase. This it later concluded, and merged the Rumney with the Brecon and Merthyr Railway, providing a complete network with dual routes to serve the industrial systems of Birmingham and the West Midlands conurbation