Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
All except previously scrapped D35 and D37 passed to Pacific National in August 2007 when BlueScope outsourced the operation of its rail network. D36, D38, D39 and D40-D45 were scrapped in 2018. D40 remains in service as a standby unit as of February 2021.
References
Oberg, Leon (1984). Locomotives of Australia 1850s-1980s. Frenchs Forest: Reed Books. p. 276. ISBN0-730100-05-7.
"Australian Iron & Steel" Railway Digest October 1986 pages 299-303