To provide for a weed spraying van, an _F__ horsebox was modified.
F 25 was converted during December 1954 and placed into service as HZ 1.
It was fitted with pumping gear and spray nozzles to spray along the track and along each side. It was coupled to tank wagons fitted with poison.
In 1959 HZ 1 was recoded to WZ 1 to clear the 'HZ' letters for a new type open wagon.
The van was placed into a special train of _WX_ / _WA_ bogie tankers. It travelled throughout Victoria on a two-three year cycle, spraying country and metropolitan tracks.
By 1982 an new van was built to replace the horsebox. _ZL_ 497 was rebuilt and renumbered to WZ 2. It too was fitted with pumps and spray gear. Most unusual was the van was painted in a very light grey colour.
WZ 1 was placed into storage at Newport Workshops and remained there until 1996 when it was scrapped and the underframe transferred to Seymour for preservation work.