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, 240 D490s 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.
The first withdrawals took place in 1904 and by 1922 only 24 D490s were in existence. The 16 D490s 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.