Feeling like you're in a rut?

by David Grand
July 30, 2008

If you're riding on a train or wagon, you might well be. For as a columnist wrote in the BNET Business Network, the U.S. standard width (width between the two rails) is 4 feet, 8.5 inches, the same as it is for wagon wheels.

As he says in this interesting, factually correct and hysterical all at the same time, is because that's the way they built them in England, and the U.S. railroads were built by English expatriates.

Why did they use that gauge? Simply because, he said, the people who built the tramways used the same jigs and tools that they used for building wagons which had that wheel spacing. And the reason wagon wheel had that odd spacing was, if they tried to use any other spacing, the wagon would break on some of the old, long distance roads in England.

Those rutted roads, he explains, were build by Imperial Rome for their legions, and have been used ever since. And the ruts were formed by Roman war chariots, which everyone else had to match for fear of destroying their wagon wheels.

Now you know, that the U.S. standard railroad gauge of 4 feet, 8.5 inches derives from the original specifications for an Imperial Roman war chariot, the size made just wide enough to accommodate the rear ends of two war horses.

Then he adds in a jocular vein, "the next time you are handed a specification and wonder what horse's ass came up with it, you may be exactly right!"

He ends by throwing in a twist to the story that was amazing to say the least:

When we see a Space Shuttle sitting on its launch pad, there are two big booster rockets attached to the main fuel tank; and while the engineers who designed the solid rocket boosters (SRBs) preferred to make them fatter, they couldn't since the SRBs had to be shipped from the factory to the launch site, and the railroad line from there required that they fit through a tunnel in the mountains.

So, therefore, the major design of what is arguably the world's most advanced transportation system was determined two thousand years ago by the width of horse's rear end.