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RE: Link to the past

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This sounds like the lady who always cut-off the leg of the chicken before baking, because her mother always
did it.  Her mother did so, because her grandmother did so.  Her grandmother did so because her great grandmother
did so.  Her great great grandmother did so because her stove was too small !!

Tradition without questioning can be a prison!


Antonio Arthay, P.E.

-----Original Message-----
From:	ECVAl3(--nospam--at) [SMTP:ECVAl3(--nospam--at)]
Sent:	Wednesday, October 06, 1999 4:00 PM
To:	seaint(--nospam--at)
Subject:	Link to the past

I thought this was interesting although you may have heard this before:

The U.S. Standard railroad gauge (distance between the rails) is 4 feet,
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

Because the first railway 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 in England, 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 their wagons use that odd wheel spacing?

Because, if they tried to use any other spacing the wagon wheels would
break on some of the old, long distance roads.

Because that's the spacing of the old wheel ruts. So, who built these old
rutted roads? The first long distance roads in Europe were built by
Imperial Rome for the benefit of their legions. The Roman roads have been
used ever since. And the ruts? The original ruts, which everyone else had
to match for fear of destroying their wagons, were first made by the
wheels of Roman war chariots. Since the chariots were made for or by
Imperial Rome they were all alike in the matter of wheel spacing.

Thus, we have the answer to the original question. The United States
standard railroad gauge of 4 feet, 8 1/2 inches derives from the original
specification for an Imperial Roman army war chariot. Specifications and
bureaucracies live forever.

So, the next time you are handed a specification and wonder, "what horse's
butt" came up with it, you may be exactly right. Because the Imperial
Roman chariots were made to be just wide enough to accommodate the
back-ends of two war-horses.

Plus, there's an interesting extension of the story about railroad gauge
and horses' behinds. When we see a Space Shuttle sitting on the launch
pad, there are two big booster rockets attached to the sides of the main
fuel tank. These are the solid rocket boosters, or SRBs. The SRBs are
made by Thiokol at a 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 from the
factory runs through a tunnel in the mountains. The SRBs had to fit through
that tunnel. The tunnel is slightly wider than a railroad track, and the
railroad track is about as wide as two horses' behinds. So a major design
feature of what is arguably the world's most advanced transportation system
was originally determined by the width of a horse's rear end. 

At least this isn't as arbitrary as limiting flexible horizontal diaphragms 
to 2x the average wall drift.