These grease axlebox wagons were originally built for coal traffic, with side and bottom doors, but no end door. On becoming surplus for coal traffic, many were reclassified as general open wagons, but the continuous top plank made them less than ideal for this work. Some were modified with a hinged top plank to avoid this. Others were put to work on loco coal duties.
Over 500 were built; most were withdrawn before the Second World War, and only six reached Nationalisation.