This type of boiler was also adapted for use on the Q and AA class 4-6-2 tender locomotives of 1901 and 1915 respectively when their original boilers wore out. In the case of the AA class, the boiler change was not necessitated by the condition of the boilers but due to the limitations of the original boilers. The replacement took place in the 1930s, and these locomotives gained new heights of reliability, before they were withdrawn in 1957 (at the same time as the Q class). All of these boilers were then put back into the AB class pool, and were reused on engines of that class.