Why the Width of a Horse's Behind is So Important

Here is a look into the corporate mind that is very
interesting, educational, historical, completely true, and
hysterical all at the same time:

The US standard railroad gauge (width between the two 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 build them like that? Because the first
rail lines were built by the same people who built the
pre-railroad tramways, and that's the gauge they used.

Why did "they" use that gauge then? Because the people who
built the tramways used the same jigs and tools that they
used for building wagons which used that wheel spacing.

Okay! Why did the wagons have 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, because that's the spacing of the wheel
ruts.

So who built those old rutted roads? 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 ruts in the roads? Roman war chariots first formed the
initial ruts, which everyone else had to match for fear of
destroying their wagon wheels. 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
ass 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.

Thus, we have the answer to the original question.

Now the twist to the story . . .

There's an interesting extension to the story about railroad
gauges and horses' behinds. When we 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
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'
behinds. 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 ass!