BR built a single batch of 80 wagons of the GWR designed 10 ton ballast wagon. Although described on the diagram as "Starfish" this branding has not been recorded. The CO mark dates back to at least 1929 on the GWR and means vehicles under the control of the Chief Office.
Drawing in Bartlett, Paul W. & Mann, Trevor., (1984a) Non hoppered Steel Ballast Wagons. GWR designs. Model Railway Constructor vol. 51 (part 599) pp 144 - 147 & 165.
