The Fylde & Wyre Antiquarian

The US standard railroad gauge (distance between the 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 English expatriates built the US railroads.

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

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? Imperial Rome built the first long
distance roads in Europe (and England) for their legions. The roads have
been used ever since.

And the ruts in the roads? Roman war chariots formed the initial ruts, which
everyone else had to match for fear of destroying their wagon wheels. Since
the chariots were made for Imperial Rome, they were all alike in the matter
of wheel spacing. Therefore the United States standard railroad gauge of 4
feet, 8.5 inches is derived from the original specifications for an Imperial
Roman war chariot. Bureaucracies live forever.

So the next time you are handed a specification/procedure/process and wonder
'What horse's ass came up with it? you may be exactly right. 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 SRB's. The SRB's are made by Thiokol at their factory in
Utah. The engineers who designed the SRB's would have preferred to make
them a bit fatter, but the SRB's 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 SRB's 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.

Excellent Frank, I'd knew about the railway and Roman connection but what a brilliant modern twist!