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