I know this has been disproved, but always liked this tale about engineering design:
The U.S. Standard Railroad Gauge (distance between the rails) is 4 feet, 8-1/2 inches or 56-1/2 inches. Now that's an exceedingly odd number. Why was that width chosen? Our research will tell you why.
The U.S. purchased their first railroad engines from England who designed & built them using expatriate engineers. Their first rail lines were built by the same people who built the pre-railroad tramways, and that's the gauge (width) they used. The tramways used the same jigs and tooling they used for building wagons which used the same wheel spacing. All other wagon manufactures used the same wheel width.
The wagons wheel ruts would ware into the roads making it impossible for any other wheel width to navigate roads both in Europe & England. The first long distance roads in Europe were built by Imperial Rome for the benefit of their legions. The same thoroughfares have been used ever since.
The initial ruts were first made by Roman war chariots. These chariots were designed to be pulled by two horses hitched side by side. The chariot wheels had to be spaced far enough apart to avoid the hoof marks left by the horses, yet not protrude past the flanks of the horses to prevent entanglement with opposing traffic or roadside vegetation. Since all chariots were made by Imperial Rome and they were all alike. Thus, we have the answer to the original question based upon our insistent research completed by the the VLC Line Engineers.
The United States Standard Railroad Gauge of 4 feet, 8-1/2 inches derives from the original specification for an Imperial Roman army war chariot. Two thousand years later and a continent away, the track layout of most of the U.S. railway network is based upon the fact that Imperial Roman chariots were made to be just wide enough to accommodate the rear-ends of two war horses. This is proof that Specs and bureaucracies live forever. So, the next time you are handed a specification just wonder if a couple of horse's behind's caused it, and you may be exactly right. ha~ha!!