Please note that, while amusing, this is mostly false. Especially the space shuttle part of the story: https://www.snopes.com/fact-check/railroad-gauge-chariots/
The article says the standard is 4' 8", and the South mostly used 5' 6". 8" variation seems like not that much when you're dealing with something as imprecise as a wagon wheel.
I don't know though. Thanks for the link.