RAILROADS: THE ROMAN RULE

The US standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches. That's an exceedingly odd number. 

The crosstie spacing of mainline railroad is approximately 19 to 19.5 inches (48 to 50 cm) for wood ties or 24 inches (61 cm) for concrete ties. The number of ties is 3,250 wooden crossties per mile (2019 ties/km, or 40 ties per 65 feet) for wood ties or 2640 ties per mile for concrete ties. The railroad gauge is consistently 4 feet, 8.5 inches from sea to shining sea.

Why was that gauge used?

Well, because that's the way they build them in England and have for a good long time. It was English engineers who designed the first US railroads. Why did the English build them like that? Because the first rail lines were built by the same people who built the wagon tramways, and that is the gauge they used.

So, why did 'they' use that gauge then?

Because the people who built the tramways used the same jigs and tools that they had used for building wagons, which used that same wheel spacing. Again, you wonder why the wagons had that particular odd wheel spacing. Well, if they tried to use any other spacing, the wagon wheels would break on some of the old, long-distance roads in England. The spacing is set by the wheel ruts in the road.

So who built those old rutted roads?

Imperial Rome built the first long-distance roads in Europe, including England, for their legions. They were not rutted to begin with but years of use ensured nice deep pits where the wheels ran through. They built the roads during their occupation from AD 43 to AD 410. Every good road and bridge across most of Europe is a testament to their skill. 

Once the roads were built, Roman war chariots formed the initial ruts. After AD 410, everyone and their dog used these same roads, matching their wheelbase to the now entrenched ruts or running the risk of snapping their wagon wheels if they didn't. 

Since the chariots were made for Imperial Rome, they were all alike in the matter of wheel spacing. So, the United States standard railroad gauge of 4 feet, 8.5 inches is derived from the original specifications for an Imperial Roman war chariot. 

Imperial Roman army chariots were made just wide enough to accommodate the rear ends of two war horses — two horses' asses. Now, the twist to the story:

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 in Utah. 

The engineers who designed the SRBs would 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 happens to run through a tunnel in the mountains, and the SRBs had to fit through that tunnel. 

The tunnel is slightly wider than the railroad track, and the railroad track, as you now know, is about as wide as two horses; behinds.

So, a major Space Shuttle 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 ass. And you thought being a horse's ass wasn't important but now you know that ancient horse's derrieres control a good number of things.