This group of tankers only really came into existence with the final demise of steam and were mostly used to supply chromated water for diesel engines. They used 1600 gallon tanks from older J class tankers withdrawn in the late sixties or early seventies whose chassis had become life expired. The new chassis came form withdrawn CXA class sheep wagons. In some cases the number of the new wagon was that associated with the tank whilst in other cases it took the number of the chassis. This group entered service as follows:

J2413 unlike (I think) the rest of the class retained the older style of tank mounting on three wooden baulks rather than the anchor plates used on most of this group. It was used with the breakdown crane and was (uniquely) painted green. The tank may have been a conversion of the 1500 gallon type. Reductions in the diesel fleet as a result of the end of wagonload freight traffic meant that some of the country depots closed and there was less need to transport chromate water around. However some of the tanks gained a new lease of life on bogie chassis as part of the JS class wagons used to move both sand and water. The class was written off as follows:

1977	919 written off
1979	12146 written off
1982	504, 713, 758 written off
1986	1213, 7327, 11336, 12088, 40418 written off
1987	2413, 10272, 10467 written off
1988	11374 written off
1991	519, 11304, 12107, 12109 written off

In parallel with the conversion of J class tanks to CXA type chassis many of the JOA class fuel oil tankers were also similarly converted. Two JOA class tanks used to transport waste oil were also branded J at the end of their careers. They were 40401 (reclassified J in 1984) and 10560 (reclassified J in 1985). They both retained their black livery with the "OA" painted out. They were written off in 1988.