There is train journey through the centre of Australia, but I've never considered making it due to the cost. I think I can fly around most of the world for the same price.
These pictures though... They are making me reconsider. Looks like you had a fabulous journey.
That's been my complaint with train travel in the US as well. Unless you are making the train a deliberate part of your trip, it's no cheaper than flying (and much more if you get a sleeper), and much slower than driving.
It's always been the cas whenever I did some research.