The S class were four powerful and heavy shunting engines, delivered by Hudswell Clarke in 1908. They bore a definite family resemblance to the R class 0-6-2T, with the same coupled wheelbase but a shorter boiler, a round topped firebox and smaller driving wheels. Their original boilers were replaced with A class boilers by the grouping. They joined the GWR as 608-611.

In 1930, all were rebuilt with superheated Standard 10 tapered boilers and new GWR style larger bunkers. They were renumbered 93-96 in the 1946 renumbering and all survived to British Railways to be withdrawn in 1953/4.

The first sketch is intended to show the class as delivered, with the round top firebox and the short lived oval number plate. This sketch should be treated with caution, since I didn't have a good drawing to work from, just a particularly rudimentary weight diagram, although I did have a good official photograph. There was particular difficulty in reconciling the proportions of cab and tank between the photograph, the weight diagram, and drawings of the class after reboilering with a GWR boiler, and I just crossed my fingers and hoped for the best.
The reboilered version of the S class is covered in this entry.