The far more numerous J39 class was a later development, exchanging the J38's 4 ft 8 in (1.422 m) driving wheels with larger 5 ft 2 in (1.575 m). Some of the J38s were later rebuilt with J39 boilers.
All J38s were withdrawn between 1962 and 1967, with the last two in service being No. 65901 and No. 65929. These two engines were the last ones designed by Gresley to be withdrawn. All engines of this class were scrapped.[1]