So why hasn't Australia done this? I would think that if you're just trying to kick the can down the road spending as little as possible in the short term, this is a possibility. But these are all going to be old alignments for lower traffic, in South America narrow gauge, and you'd have to invest in ooncrete ties, new rail, etc anyhow. Plus the new construction needed for both projects. Not sure if this has ever been more than hype.