From the late 1920's, two _TT_ boxvans were used on passenger trains as baggage vans. They were numbered TT 15 and TT 18.
Both vans were fitted with autocoupler draft gear in 1933 and were fitted with transition hook coupling gear. Both vans were indicated in correspondence as "Mail Baggage Vans" and derated from 23 ton capacity to 15 ton capacity.
In 1941 both vans were modified with "Pass type bogies". TT 15 was modified again in 1946 with "Pass type bogies".
In 1956, both vans were reclassed to TP, with numbers retained.
The vans only ran in service for about twelve months before being recoded again. In this recoding they became BP 15 and BP 18.
With the introduction of more steel vans to be coded _BP_, BP 15 and BP 18 were renumbered to BP 1 and BP 2. This is the reason that the steel _BP_ group starts at number 3.
It appears that these vans ran on the "Overland" train between Melbourne and Adelaide. A photo of this train in the mid 1950's shows a van of this type in the consist.
Both vans were scrapped in November 1960.