GWR 4100 Atbara/Flower Class

The GWR Flower Class was a series of inside-cylinder 4-4-0 express passenger locomotives designed by William Dean and built at Swindon Works in 1908, named after flowers and forming one of the later groups of Dean-derived 4-4-0s that Churchward was progressively updating or withdrawing as he developed his own modern express types. The Flower Class was closely related to the Atbara Class of 1900–1901 and used essentially the same design specification, with Churchward's long-travel valve gear improvements applied from the outset.

By 1908 Churchward's new outside-cylinder express types — the Saints and later the Stars — were clearly the future of GWR express locomotive practice, and the Flower Class 4-4-0s occupied a secondary role from the beginning, working the semi-fast and cross-country express services rather than the principal main-line expresses. Their flower names — Anemone, Begonia, Carnation, Dahlia, Mignonette and others — gave them a distinctive identity among the GWR's named classes.

The Flower Class was a relatively small group and gave useful but unremarkable service on GWR secondary express duties. Withdrawals came in the 1920s and 1930s as Churchward and later Collett designs took over all express and secondary express working. None was preserved.