 Ten further DG class engines - nine built by Vulcan Foundry and one by RS&H - were given "A-grade" overhauls to work as trailing B-units for the rebuilt locomotives.These locomotives did not receive new cabs, and as such were not to be driven in regular service.A number of other locomotives of this type also received the updated Westinghouse 26L brake system and NZR designed push-button control stand.