Eventually, the rail beds will fail along with the rest of the remaining infrastructure. We may see something like the Cambodian killing fields before the final collapse of southern Africa. Zimbabwe is just a forecast of the chaos that is coming to Namibia and South Africa IMO.
Hey, maybe in 50-60 years, there will be enough vacant land there to establish a new, constitutional Republic. Either that, or we can trick the Libs into all moving there to try to "save" Africa.