A typical Welsh Valley Motive Power Depot situated some four miles or so north of Cardiff on the line to Pontypridd and Merthyr , the allocation locomotives at Radyr comprised wholly of tank engines so necessary for working the Welsh Valley lines , with some fifty or so locomotives on its books in the mid ' fifties.
Dating back to 1866 on the Taff Vale Railway , and being rebuilt by the Great Western Railway in the early ' thirties ,Radyr was a sub shed of 88A Cardiff Cathays until December of 1957 when its status was increased and it exchanged roles with Cathays , with Radyr becoming the principal Depot and thereby reducing Cathays to sub shed status .
" Taffy Tank " 5669 seen here was one of the initial batch of one hundred of the class specifically introduced by Collett for duties on the Welsh Valley lines , being built at Swindon from 1924 , distinctive with their inside cylinders , popular with footplate crews and capable of working bunker first on the valleys particularly where no turning facilities existed at the end of the line .