Between 1884 and 1903 the GWR built 301 tenders with a water capacity of 2500 gallons, all to basically the same design. These tenders were used with many classes including 2-4-0s, 2301 class, Krugers, Aberdares, 3521 class, Dukes and Bulldogs.

There were many modifications made to the basic design during the 19 years over which the tenders were in production and many more subsequent changes as they were rebuilt.

The earliest tenders had coal rails and no water scoop. The water filler was a cylindrical casing and the sandboxes were mounted on the footplate in front of the tank. They also had identical toolboxes on each side and some were fitted with an overflow pipe and fountain for use with engines equipped with crosshead driven water feed pumps.

Later tenders were fitted with a water scoop and a combined water filler/scoop fountain. The front of the scoop was subsequently fitted with a plate presumably to prevent 'foreign bodies' entering. These early tenders also had a "drop" in the flare on the tank sides at the front, front steps with a curve on the leading edge and hornguide ties of the rod type.

From Lot A36 the flare on the tank sides was carried through to the front, the coal rails were extended forward and the footplate widened at the front. These tenders were built for the new 4-4-0s and consequently had a raised footplate at the front. They also had front steps with a straight leading edge and strip type hornguide ties.

Subsequently all were rebuilt with coal plates, a different pattern toolbox on the left hand side and fire iron trays and were fitted with water level gauges. Most appear to have had the sandboxes removed and replaced by a single sandbox on the left hand side at the front of the coal space, Some were also fitted with separate pickup domes and water filler. Because of the relatively small coal space this involved cutting an opening in the rear coal plate for the dome to fit through.