Thank you for the photo of Wauchope Railway Bridge with the flood waters underneath.
Looking at the actual bridge, it seems there is a fair amount of rust on the steel beams?
Does the bridge have a rust problem?
The photo does not show problem rust, you can't see such problems from such a distance until it is extreme.
The paint IS wearing thin (literally) and showing the red lead primer, and it is time for this bridge to receive some love.
Note, paint is not to make the bridge look good, it is a protective coating, nothing else.
The 'yellow' bridges built by Chullora during the 70s & 80s have a chemically bonded protective coating. They have a plaque riveted onto the main girders stating that they are NOT to be painted, but to contact the principal structures engineer if there is a concern.