With a rise in housing development in the early 1960's, the timber traffic out of the Orbost region of East Gippsland grew. As a result, about 270 vehicles of _I__ and _IA_ wagons of 15' wheelbase were modified to provide a special vehicle for scantling timber traffic. After trials with one wagon, the class letters IT were adopted. In some cases, other wagn classes with I / IA heritage were used.
The IT number group was 1 - 273.
As scantling timber was packed by the sawmills into 'packs' there was a problem with the load distribution. Each 'pack' consisted of various lengths of sawn timber (scantling) which were stacked with all ends together at one end. To overcome the load problem the IT vehicle had three distinct features:
Despite extemely uneven loading, derailments were fairly rare. More common was the sight in shunting yards of loaded IT wagons 'rearing up like stallions' when hit roughly from the heavy end during shunting.
By the late 1980's, building construction was using different materials and hardwood was in decline. With reduced traffic, less IT wagons were required and these were replaced by standard wagons with less loading in them.
A batch of bogie wagons were built for timber traffic, coded VFTY. These vehicles, as well as _GY_ and _G__ wagons , gradually replaced the IT wagons in traffic.
There were three main types of IT wagons:
Were built "back to front", with the handbrake at the bulkhead end.
Wagon IT 252 was an experimental vehicle, a stretched version of a _KT_ truck. As the vehicle was a 22 ton capacity truck and different design, it was recoded to the _KS_ group later.
Wagons were built with the bulkhead at the "heavy" end ( ie 22t axlebox/journals/springs) on the non handbrake end.