Things Engineers Wonder About
The US Standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches.
That's an exceedingly odd number.
Why was that gauge used?
Because that's the way they built them in England, and the US railroads were built by English expatriates.
Why did the English people build them like that?
Because the first rail lines were built by same people who built the pre-railroad tramway's and that's the gauge they used.
Why did "they" use that gauge then?
Because the people who built Tramways used the same jigs and tools that they used for building wagons which that wheel spacing?
Well if they tried to use any other spacing the wagons would break on some of the old, long distance roads, because that's the spacing of the old wheel ruts.
So who built the old rutted roads?
The first long distance roads in Europe were built by imperial Rome for the benefit of their Legions.
The roads have been used ever since.
And the ruts?
The initial ruts, which everyone else had to match for fear of
> destroying their wagons, were first made by Roman war chariots.
Thus we have the answer to the original question.
The United States standard railroad gauge of 4 feet,8.5 inches derives from the original specification for an Imperial Roman army war chariot.
Specs and Bureaucracies live forever.
So, the next time you are handed a specification and wonder what horse's rear end came up with it, you may be exactly right.
Because the Imperial Roman chariots were made to be just wide enough to accommodate the back-end of two war horses.