Llantrisant and Taff Vale Junction Railway
In time the Canal became overwhelmed by the volume of traffic, and encouraged by the successful opening of railways with more advanced technology than the horse tramways of previous years, the Taff Vale Railway was promoted. It was authorised by Parliament in 1836 and it opened between Merthyr and Cardiff docks in 1841. The line passed close to the Maesmawr workings but did not make a connection.
Cardiff Railway
The Taff Vale Railway was alarmed at this development, as it could only result in traffic, and income, being diverted from its line to the Cardiff Railway. Having found success, the Cardiff Railway promoted a further Bill in the following session, and was authorised on 12 August 1898 to build a railway from Roath Dock to its newly authorised line, joining the Rhymney Railway near the junction. Also proposed in the Bill was a new line from Heath Junction to the Docks, which would have made the Cardiff Railway independent of other lines at the southern end, but this was rejected by Parliament.