Not entirely clear how you'd use rail infrastructure to go from Addis Ababa to DC, so if you need the aviation infrastructure for intercontinental travel, its c

Not entirely clear how you'd use rail infrastructure to go from Addis Ababa to DC, so if you need the aviation infrastructure for intercontinental travel, its cheaper to use the same infrastructure for both. Kinda like the classic problem of "why don't rockets use atmospheric oxygen for the first 5% of their flight" well, its just not worth it. Another BIG problem is urban people think rails go everywhere and connect everything. An interesting geographic feature to google for is "darien gap" in Panama. Most people refuse to believe there is no road connection between north and south America... We don't even have paved roads crossing Panama in 2019... We're simply not going to have high speed rail between the USA and Cape Horn in our lifetimes due to engineering challenges. https://en.wikipedia.org/wiki/Darién_Gap https://en.wikipedia.org/wiki/Darién_Gap One of those interesting engineer's daydreams is building a rail connection across north and south america. Imagine a really cool bridge across the panama canal. The problem is there's no market. High speed (human) cargo gets put on the planes because the countries need aviation infrastructure for intercontinental trade anyway. Low speed (metal ore or bulk grain) cargo takes boats which use about half the energy and cost of rail with essentially zero environmental or property tax impact (well, zero compared to rail or road, anyway). So what has to move faster than people but slower than coal... well... nothing, I guess. So no market means no infrastructure.