 Their working steam pressure was , and they had diameter cylinders with piston strokes.The handsome UD locomotives were more than capable of making up lost time, with mile-a-minute runs recalled with pride by Manawatu railway employees.Due to their power, the locomotives were capable of hauling mail trains without the need for a banking locomotive from Paekakariki south to Pukerua Bay, and were used principally on mail trains north of Paekakariki.