WOW,,, i posted a stumper…. Thanks to everyone who answered and those that know the answer, because they are smart little possums.
Daisy was close with the idea of the width of a wagon, but what was in front of the wagon was more important. And Anonymous who ever that was, had the right distance at 4 feet 8.5 inches. This is the gauge of the standard railroads in the US even though there are still some narrow gauge railroads around. BUT why this strange number. While Wikipedia has a nice description, i sort of like the ‘urban legend’ one. Now i can’t confirm this but in Great Britain horses were used to pull coaches before the steam engine was perfected. AND if you put two British horses side by side their asses measured 4 ft 8.5 inches. So there you have it, the width of two British Horses Asses.