The Port Talbot Railway Stephenson Class were eleven 0-6-2T locomotives introduced into traffic in 1898 designed and built by Robert Stephenson and Company. They predated the somewhat similar but larger Rhymney Railway M class by six years. They were successful designs ideally suited to hauling coal trains a relatively short distance. Four of the class were nevertheless quickly sold, two to the Rhondda and Swansea Bay Railway in 1901, and two more to the Neath and Brecon Railway in 1903. This left seven to be absorbed into the Great Western Railway (GWR) in 1922.