The AP fleet was initially relettered to APT, and the BP fleet to BPT. When the classes were simplified in 1921, only 39 APT and 28 BPT cars had been refitted with the required electrical equipment. Further conversions were straight from AP/BP to T. From 1922 on, ex-AP cars had 200 added to their numbers to indicate the Tait/Sliding door fleet; for example 37AP became 37APT then 237T. The ex-BP cars were renumbered into the range 287-348, keeping the sequence i.e. 1BP became 287T and 62BP became 348T.