Built at Derby from 1881, these Clayton bogie arc roof carriages had a strong similarity to the contemporary 6-wheeled arc roof stock. Although not as plentiful as the 6-wheelers, 110 D502s were built. 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.
In 1892 some were converted to lavatory brake thirds by replacing the centre compartment with two lavatories. Seven were converted in 1907 to driving brake thirds for motor train working, and sufficient parts are included in the kit for this. The four D502s purchased by the Midland & South Western Junction Railway before the Great War survived to receive their GWR numbers and were finally scrapped in 1924/25.
The final LMS withdrawal occurred in 1934, one of only two to get as far as the 1933 LMS renumbering.