Pig iron wagons were essentially a short haul, heavily loaded, extremely robust carrying bed for a most uncompromising traffic. Their area of activity would have been the industrial heartlands of Scotland, moving pigs from furnace to rolling mill. When required, these wagons were also used for a variety of traffic including barrels, crates, cotton bales etc.
First built before the turn of the century, these wagons were introduced as an 8 ton wagon, which was later uprated to 10 tons. Over the years the brake gear would have been modified from the single shoe one side pattern to single shoe both sides and perhaps to the conventional either side pattern. Wagons repaired or built after 1911 were required to have a two-lever system but it is unlikely that many were altered.
A later 14T version featured heavy-duty Iracier grease axleboxes and self-contained buffers, and this is the subject of 51L kit CRD016L.
At least 1300 diagram 16 wagons were produced of which 550 were 8/10T and 750 are thought to have been 14T wagons.