The Taff Vale Railway A class was a class of 0-6-2T steam tank locomotives designed by J. Cameron for mixed traffic work and introduced to the Taff Vale Railway (TVR) in 1914. The A class was an enlarged version of the TVR O4 class designed by Tom Hurry Riches in 1907. The A class was the last new class of locomotive to be introduced on the TVR, which had introduced its first 0-6-2Ts in 1885 (the ); and, with a total of 58 built, was numerically the largest class of tank locomotive on the TVR.