Dennis and I are down in Dallas, Plano actually, visiting our son and his family. Part of the purpose for the trip was for Dennis to attend a warehousing conference in Houston. I had already been at our son’s for a week so I went with Dennis to Houston and had a 3 day vacation.
One of the pieces of information from his conference that he shared with me on our 5 hour drive back up to Dallas was a bit of history on the width of railroad tracks. It was given as an example of people doing things a certain way because that’s the way it has always been done.
So now, do you know why railroad tracks are the width that they are? It is because of horses.
The Canada and US standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches because that's the way they built them in England, and the US railroads were built by English expatriates and they are the same people who built the pre-railroad tramways, and that's the gauge they used.
The people who built the tramways used the same jigs and tools that they used for building wagons, which used that wheel spacing.
They used that wheel spacing because if they tried to use any other spacing, the wagon wheels would break on some of the old, long distance roads in England, because that's the spacing of the wheel ruts.
The first long distance roads in Europe (and England) were built by Imperial Rome for their legions. The roads have been used ever since. And the initial ruts, which everyone else had to match for fear of destroying their wagon wheels, were first formed by Roman war chariots.
Since the chariots were made for (or by) Imperial Rome, they were all alike in the matter of wheel spacing. The United States standard railroad gauge of 4 feet, 8.5 inches derives from the original specification for an Imperial Roman war chariot.
Specifications and bureaucracies live forever. So the next time you are handed a specification and wonder what horse's backside came up with it, you may be exactly right, because the Imperial Roman war chariots were made just wide enough to accommodate the back ends of two war horses. So now we have the answer to why tracks are 4 feet, 8.5 inches apart.
But it doesn’t end there -
When you see a Space Shuttle sitting on its launch pad, there are two big booster rockets attached to the sides of the main fuel tank. These are solid rocket boosters, or SRBs. The SRBs are made by Thiokol at their factory at Utah.
The engineers who designed the SRBs might have preferred to make them a bit fatter, but the SRBs had to be shipped by train from the factory to the launch site. The railroad line from the factory had to run through a tunnel in the mountains. The SRBs had to fit through that tunnel. The tunnel is slightly wider than the railroad track, and the railroad track is about as wide as two horses walking side by side.
So, the major design feature of what is arguably the world's most advanced transportation system was determined over two thousand years ago by the width of a horse’s butt