Initially a fleet of 55 hopper wagons built in 1971 by Standard Wagon for BP Salt traffic. They were unusual in having arrangements for a plastic coated cover. They went out of this traffic about 6 years later. Many were condemned because of corrosion (I believe all those in this collection at York are awaiting withdrawl). Others were refurbished, and later had Bruninghaus suspension and continued in china ball clay and aggregates traffic.