In addition to supplying 81 O.305 and 5 O.305G buses to ACTION in the 1980s, Mercedes-Benz provided one further O.305 vehicle to the Department of the Capital Territory: a purpose-built Mobile Library bus.
ZIO-999 was built by Ansair Tullamarine for use by the Canberra Public Library Service to replace its former mobile library which was a trailer towed by a truck.
It commenced operations on 30 October 1984. The bus was fitted with wooden shelving, a microfiche catalogue system and an access ramp at the entry. It was driven to locations such as Hall and Tharwa as well as retirement and nursing homes.
The Mobile Library bus was retired from service in 2004, replaced by mobile library vans.