Burdekin bridge.

Early on our trip away Olivia snapped this shot of us crossing the Burdekin River bridge between the towns of Ayr and Home Hill, it's rather an outdated engineering marvel now but the difficulties of making a new bridge will be quite a costly hurdle.
It was completed in 1957, some would say it was a great year but the difficult thing about it is that nobody has ever dug deep enough to find a solid foundation to build on, something that creates quite a challenge for engineers.
As it stands now it's too narrow for current standards but is very valuable as a link, even the rail shares this bridge.