I am fairly certain that the photos of B18 1/4 No. 27 at the north end of the yard and and BB 1073 and PB15 105 are at Mackay, the sugar boxes are the confirmation.
The other two photos are at Bundaberg, 569 is has just come off the bridge over the Burnett River and is crossing Burbong Street.
1617 is on the same road crossing which is at the end of Bundaberg station.
I have forwarded the photos to Arthur Hayes and Brian Webber, both spent some time in Mackay in the days of steam, Arthur a a fireman and Brian as a railway enthuasist and photographer.
The locomotive 105 is a C16 not a PB15. The C16s when rebuilt with the "Master Mechanics Front End" were the only QR locos with the distinctive tapered funnel.
The numbers are interesting as QR reallocated locomotive numbers. For example of B18 1/4 No. 27 was built in 1935 after C16 No.105.
Back when I was a young lad I thought that PB15 No. 5 was QR's the fifth loco, it was all very confusing especially as there was a C17 No. 2.
Incidentally when I joined QR in 1981 my service number was lower than others with longer service, another QR venture into the world of recycling.
QR also recycled bridge girders, so far I have found 65 instances, some for rail bridges and others for road overbridges.
Others were sold to The Main Roads Department and sugar mills for reuse.