New South Wales Transport Museum stages this event over the 3 days of Queens Birthday Weekend in June. This year's event added steam boats to the mix of buses and old trains.
To start with a bang, the first event on Saturday is the Great Train Race, wherein 2 (or 3) trains "race" from Central to Strathfield station. After that event, there are scheduled shuttle services from Central, mostly to Hurstville, but the rail motors had 2 unusual routes - one via Olympic Park station, and the other along the freight lines normally inaccessible to mere mortals.
Information on Garratt locomotives:- https://en.wikipedia.org/wiki/Garratt
This particular Garratt:- https://en.wikipedia.org/wiki/6029
Parkes Radio Telescope: https://en.wikipedia.org/wiki/Parkes_Observatory
Open Day program: https://events.csiro.au/Events/2018/November/26/Parkes-Open-Days-2019
Cowra Japanese Garden: https://en.wikipedia.org/wiki/Cowra_Japanese_Garden_and_Cultural_Centre
Margaret Hamilton in moonlight: https://www.blog.google/products/maps/margaret-hamilton-apollo-11-tribute/
Note: Margaret Hamilton wrote the software for the lunar module!