(Sorry, I know it's a model thing, but also a massive moment for Tasmanian modelling!)
From the Queensland modellers facebook group
I only know what was posted here:From: https://www.facebook.com/Hobart-Model-Railway-Group-689447087801699/
I'm guessing it's all coming out for the Brisbane Model Railway show this weekend, since SDS is there and the 1620 is a part of it.
Damn I wish they'd snuck a ZC/1300 in as well they're so close...
edit: yes, HOn3.5 as well as HO, late 2022 planned release.