The J39 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), 289 J39s being built. Some of the J38s were later rebuilt with J39 boilers.
All J38s were withdrawn between 1962 and 1967, with none surviving into preservation and falling to the cutter's torch. Though rumors persist about plans to build a replica of this steam locomotive some time in the near future, along with the LNER J39 steam locomotive.
Sources
Ian Allan ABC of British Railways Locomotives, 1962 edition