BR introduced a novel design of large flat bottomed mineral wagon in 1952. They continued building them until 1962 with a total of 3395. The only diagram change was to record the later wagons having roller bearings from new and twin door stops. None were vacuum braked and the design went out of use in 1981 (the photographs in this collection at Wellingborough were the last wagons moving to internal use in Yorkshire). Some of the number series continued in use for a few years as some underframes received new single door bodies. By 1968 some had lost their side doors and were branded 'NO DOORS'. Parkside make both 4 and 7mm kits of these wagons and full number series and drawings have been published in Bartlett et al (1985).