In about 1985, the class of _HR_ was subdivided into various groups. By this time, the HR group was catering for different transport needs and with replacement vehicles it was difficult for the rail administration to keep track.
A new group of brake block transport wagons were converted in 1985. The class was HZB. Numbers 280 to 300 were converted from surplus _GY_ and _G__ wagons.
HZB 301 to 309 were converted from HR 66, 69, 80, 81(2nd), 82(2nd), 83, 105, 107 and 108 respectively.