 Their rigidly mounted leading and trailing carrying wheels were also arranged as radial axles to allow for sideways motion of the wheels in relation to the locomotive frame, since the locomotive did not have separate bogie trucks.As on the Class Hd, this resulted in a rigid wheelbase of , even though the leading carrying wheels were arranged to the rear instead of ahead of the cylinders.In service, these six locomotives and the three Class Hd locomotives were operated in a common pool.