In 1909, the Brecon & Merthyr introduced a series of 0-6-2T radial tank locomotives which were considerably heavier and more powerful than the locomotives delivered in 1894. Another difference was that they had side tanks instead of a saddle tank. The requirement had stated that they must be able to haul the equivalent of ten and one-third loaded ten-ton wagons up an incline of 1 in 40 or 2.5 percent. Four each were built in 1909 and 1914. To enable them to work the heavy passenger traffic in the summer season, they had received the automatic vacuum brake. Since it was found that they had drivers too small for passenger traffic, three other locomotives were built for this task in 1915 where the diameter had been increased by six inches. In 1923, all were taken over by the GWR.