Built at Derby in 1884, these 20 Clayton bogie arc roof carriages had a strong similarity to the contemporary 6-wheeled arc roof stock. It is possible that these carriages were originally built with oil lamps but would have been converted to gas by 1902 in common with the 6-wheel stock. Both types of lighting are provided for in the kit. It is likely that torpedo vents were fitted in the early years of the 20th century. Two D526s were transferred to the M&GN in 1902, and withdrawn in 1919. Some vehicles were altered by the addition of lavatories, and at least seven became driving brake composites around 1907. Only a few survived to the Grouping and the last was probably withdrawn by 1930.