The Taff Vale Railway A class was a class of 0-6-2T steam tank locomotives designed by J. Cameron and introduced to the Taff Vale Railway in 1914. The A class was an enlarged version of the Taff Vale Railway O4 class designed by Tom Hurry Riches in 1907. 42 of the A class locomotives were rebuilt with taper boilers and superheaters by the Great Western Railway (GWR) and vacuum brakes for passenger working in 1924.