Swindon railway works built 260 of these goods locomotives between 1883 and 1899 to a design of William Dean. The 2301 class broke with previous GWR tradition in having inside frames only and changes were made in the boiler design during the period that they were being built. The first twenty engines were originally domeless though all were provided with domed boilers in due course. They were numbered 2301–2360 and 2381–2580 (2361–2380 were of the 2361 class, which were similar visually but had outside frames).