How Specifications Live 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 people 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 very wheel spacing.

Okay!  Why did the wagons use that odd wheel spacing?  Well, if they had
tried to use any other spacing the wagons would break on some of the old,
long distance roads, because that was 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.  Those roads
have been used ever since.  And the ruts?  The initial ruts, which everyone
else had to match for fear of destroying their wagons, were first made by
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 questions.  The United State
standard railroad gauge of 4 feet, 8.5 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 ass came up with it, you may be exactly right.
 Because the Imperial Roman chariots were made just wide enough to
accommodate the back-ends of two war horses.

From: Wes