Watco is reportedly the new GrainCorp operator in Queensland, taking over operations in November 2019. It is rumoured to have outbid SSR for the narrow gauge contract. It isn't immediately clear what rollingstock it will use, however the equipment available to it in Western Australia can be ruled out - both by ownership and being out-of-gauge for the QR and Aurizon networks. It can be anticipated the equivalent of four 39-wagon 63-tonne gross grain sets will be needed by the new operator with at least seven locomotives capable of operating on QR's 15.75-tonne axle load grain network west and south west of Toowoomba.
The Central Queensland grain network will be almost entirely on Aurizon's 26.5-tonne axle load network by next year, with the exception of the Moura silos (QR's short section of mothballed 15.75-tonne track from the Aurizon line), QR's North Coast Line from Yukan to Erakla and the Mackay Harbour branch from Erakala - the later two lines are 20-tonne axle load.
Queensland's grain crop can be highly variable, with production reaching 2.5-million tonnes some years, but is frequently under 500-thousand tonnes.
The world appears to be awash with surplus metre gauge sub 15.75 tonne locos at the moment
India is rapidly converting its metre gauge network to BG
A quick phone call to RITES (IR's quango disposal agent) should solicit an offer of YDM-4https://en.wikipedia.org/wiki/YDM-4
There are possibly 200 surplus YDM-4 rusted to rails in India at the moment. This model is a third world special, totally bullet proof, has survived atrocious conditions in Mozambique, Tanzania, Sudan, Benin, Senegal, Vietnam, Malaysia, Myanmar, Bangladesh, etc. Bogie frames accommodate Cape gauge conversion https://www.youtube.com/watch?v=YCBR7fv9e7shttps://www.youtube.com/watch?v=rF1gguXFx8k
Or DLW will build new with current generation breaking, dynamic brakes, digital control. 18 new build delivered to Myanmar last year http://www.dlw.indianrailways.gov.in/works/uploads/File/_DSC7817%201.jpg
If India and these third world nations can't break them, they should survive on the wet sphagetti that passes for rail in rural Qld.