(Sorry for this off topic message, but I thought some of you might find it
Good engineering lasts forever!
The U.S. standard railroad gauge (distance between the rails) is 4 feet, 8.5
inches. That is an exceedingly odd number.
Why was that gauge used?
Because that's the way they built them in England, and the U.S. railroads
were built by English expatriates.
Why did the English build them that way?
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?
Because the people who built the tramways used the same jigs and tools that
they used for building wagons, which used that wheel spacing.
So why did the wagons have that particular odd 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 was 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?
The ruts in the roads, which everyone had to match for fear of destroying
their wagon wheels, were first formed by Roman war chariots. Since the
chariots were made for (or by) Imperial Rome, they were all alike in the
matter of wheel spacing. The U.S. standard railroad gauge of 4 feet-8.5
inches derives from the original specification for an Imperial Roman war
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 end of two war
horses. Thus we have the answer to the original question.
Now for the twist to the story. When we see a space shuttle sitting on it's
launching pad, there are two booster rockets attached to the side 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 might 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 had to run through a tunnel in the mountains. The tunnel
is slightly wider than the railroad track, and the railroad track is about
as wide as two horses' rumps. So, a 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!
Don't you just love engineering?
Mark Swink, CD
Anderson Design Detailing, INC.
425 W. Plainview Rd. STE. 1A
Springfield, MO. 65810
Phone: (417) 823-0500
Fax: (417) 823-0505