The line was authorised as a tramroad in 1812 to connect Pentyrch ironworks (nprns 34111 & 34112) and Melingriffith tinplate works (nprn 40456). It was converted in 1871 to a standard-gauge railway and extended northwards to a junction with the Taff Vale Railway at ST 117843. A number of discarded stone sleeper blocks remain on the river bank. A (replacement) iron girder bridge (nprn 91549) carried the line across the River Taff near the sixteenth-century Cilynys farm. The line crossed the TVR on the level near the surviving original TVR Pentyrch railway station building of 1841.
Source: A Guide to the Industrial Archaeology of South East Wales, AIA, 2003.
B.A.Malaws, RCAHMW, 12 August 2005 & 25 July 2013.