A mystery solved, the old Tropic of Capricorn marker still exists.

I saw an old family photo of a marker for the Tropic near Rockhampton 45 years ago but in my travels have never found one on the Bruce highway, with most folk wrongly thinking the huge tropic marker at the info centre near the southern edge of town marks it, but it's out by a few km.
These markers are on the old Port Curtis road which I have to believe was the highway before being bypassed. They're overgrown now but their purpose has long gone, in reality the Tropic has moved north to somewhere near that lone tree on the right side of the road since the highway moved, but this just solves what to me has been a long term mystery, thanks to earth and street Google.