The company of Andrew Barclay Sons & Co. was known for manufacturing very robust small shunting and narrow-gauge tank locomotives. These engines mostly went to industrial plants, but also to some larger companies. An example of this was the “Alexandra” built in 1901 for the Alexandra (Newport and South Wales) Docks and Railway. It was a six-coupled, standard-gauge shunter and bore the works number 911 from Barclay. It was also described by the Locomotive Magazine as being extremely stable and had a copper firebox, the material of which being manufactured to the quality standards in the production of artillery shells.

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.

Starting in 1882, this joint railway operated three tank locomotives with a 2-4-0T wheel arrangement for use with passenger trains. These were a standard Beyer, Peacock & Co. design with five and a half foot diameter driving wheels. Number 6 is recorded as later being sold to the Wight Central Railway. In 1884, a slightly larger machine from the same manufacturer followed, bearing the number 8.