From 1936 a group of seven older brake vans was rebuilt with new bodies (type 15a). Most had 4'-10" wheelbase brakevan bogies. However Z15 retained 5'-6" carriage bogies. These vans formed the pattern for a batch of eight new vans built in 1946 (Z221-8), which used old coach bogies (type 15b). The type 15a vans were numbered as follows:
ZG15 rebuilt March 1942 using the frames of Z111. Reclassified Z15 October 1943 was fitted with electric light February 1956, written off in May 1975, written back March 1976 and finally written off in November 1985.
Z34 written off August 1965
Z51 written off February 1968
Z72 written off October 1961
Z73 written off August 1963
Z93 written off April 1982
Z107 written off March 1969
Z142 rebuilt April 1944 written off April 1973