I’m sending this (and another behind it) to the USMA list, so you
can get a better idea of the discussion between Andy the
conservative civil engineer and some of the other members of the
“All Aboard” passenger railroad list. I hope I didn’t get too much
wrong in what I wrote.
Carleton
------------------------------------
From: [email protected] [mailto:[email protected]]
On Behalf Of Carleton MacDonald
Sent: Saturday, March 07, 2009 18:12
To: [email protected]
Subject: RE: [A_A] Re: OT: metric
Actually, you are working in metric, it's just hidden.
You are using the "metric inch", which since 1959 has been officially
defined as 25.4 mm - EXACTLY, and by definition (no longer "three
grains of
barley, dry and round, placed end to end"). All the other, and many,
names
for length (foot, yard, mile, rod, chain, etc. etc. etc.) are
derived from
that.
The "pounds" you use are defined as exactly 453.59237 grams.
And since the "gallon" is legally defined (in the USA anyway) as 231
cubic
inches, and the definition of the inch is based on the millimeter, the
gallon is hidden metric as well: 3.785411784 liters, again, exactly.
Historically, there have been over fifteen different gallons - but
only one
liter.
So you're already doing your work in metric. You're just using funny
multiples of it, with a whole host of different names. To get an
idea of
just what a muddle it all is, look at this document from the National
Institute of Standards and Technology, just down the road in my home
town of
Gaithersburg, Maryland:
http://ts.nist.gov/WeightsAndMeasures/Publications/upload/h4402_appenc.pdf
Strip out all the "customary" or "imperial" stuff, and see how much
shorter
it would be. The metric units take two pages. The "customary" and
"imperial" units take up the next nineteen! Of the metric multiples,
the
only ones in common use are mega, kilo, and milli; the size of the
number
varies of course.
The customary measures have dozens of names for length, mass, volume,
depending on what is being measured, and in what country. The metric
system
has one name, only, for each ("kilometer" and "meter" are not two
different
names, one is just a multiple of the base unit). Enough metric for
daily
life can be taught in a couple of hours. Schools spend months on
customary
units. Please do not tell me customary is easier - this is not true
at all,
it's just what you are used to. (Understood, a civil engineer's
training
goes far beyond what the average Joe the Plumber is taught, or even
needs to
know.)
And a manufacturer would not call a 59 ft 6 in wheelbase "18135.6" mm.
That's an overly-precise conversion derived from multiplying the
length in
inches ([(59 x 12) + 6] = 708 + 6 = 714 in, annoying, that extra
step) by
25.4, the official length of the "inch", and not rounding. It is
highly
unlikely that the vehicle is exactly 59 ft 6.0000 in long anyway;
the extra
0.6 mm is a precision that is probably not there. The manufacturer
would
probably just specify it as 18135 mm. Easy to convert that to meters
(move
the decimal point three places); a bit harder to convert 708 inches
to feet
and inches, or yards and inches, in your head.
To keep this railroad oriented: A number of years ago we were buying
new
ticket printers for the stations. The manufacturer was IER, a French
company, so the specifications were in metric. These were thermal
printers,
meaning they burned the image on the ticket with heat (the tickets are
thermally sensitive, which is why you don't leave them in the car on
a hot
day, or laminate them) rather than using a ribbon or ink roller.
There is
one long-term replaceable component inside, the print head. The
specifications stated that the print head was normally good for
about 100 km
of tickets. (And only in a non-metric country would anyone think that
"kilometer" is only for measuring road distance.) They asked me how
many
tickets that would be.
I paused for about five seconds, then said, "500 boxes of tickets."
"How did you do that so fast?"
"Easy. Each ticket is 200 mm long. (Eight inches, really, but close
enough
for this estimate.) That's five to a meter, 5000 to a kilometer, and
500,000 to 100 kilometers. There are 1000 tickets in a box, so, 500
boxes.
Easy, when you use the right units."
Now, answer that question in your head when the figures are "eight
inches"
and "62 miles".
Everyone I speak with, at work, church, the neighborhood, wherever,
wonders
why the US didn't make the change decades ago. The only ones who have
heartburn over it are those who hate, absolutely hate, the idea that
"gummint" is going to "tell me what to do".
Done properly (which wasn't done thirty years ago), with an
educational
campaign and industry participation, the whole thing could be done
in a
year. Australia did.
OK, I'm done.
Carleton
From: abyler
Sent: Saturday, February 28, 2009 09:59
To: [email protected]
Subject: [A_A] Re: OT: metric
--- In [email protected], "Gary R. Kazin" <gka...@...> wrote:
>
>
> You DO use the metric system; you just don't realize it.
Yes, important sectors of the economy like the illegal drug business
are all metric. (/sarcasm)
> Every time you buy large soft drink bottles, they are metric: one
> liter, two liters, even three liters.
No, they are filled in a metric manner with air left in the top.
There is nothing magical, mytsterious and metric about them. 2 L =
67.6 fl. oz. Close enough to half a gallon, which is 64 fl. oz. It
would be no trouble at all to just fill the same bottle to 64 fl. oz.
and call it the "half gallon" bottle. In fact, just like there are
metric "pounds" and "tons" in use in "metric" countries overseas, I
suspect that Americans would probably come to call a 4 L size
a "metric" gallon if they were forced to buy milk or gas by the liter.
> Every time you buy liquor, it is metric: 500 ml, 750 ml, one liter.
This was forced on the industry by the government. The bizarre sizes
like 750 mL and 1.5 L come from trying to keep bottles close to the
old fifth. Another example of how "eager" everyone is to adopt this
stupid system, that it must be stuffed down their throats with the
threat of government police power behind it.
> All the nuts and bolts in your car are metric. The tires are
described by metric measurements, except for the diameter of the
wheel.
>
> And, getting back to railroading, most passenger rail cars are
> designed using metric measurements - the manufacturers are
> foreign-based companies.
I'm curious if this is really true. An 85' car would be 25908 mm. A
59'-6" wheelbase would be 18135.6 mm. The 10'-6" overall width would
be 3200.4 mm.
Somehow, I doubt it. I suspect the drawings are done in customary
units because the reviewers in this country are used to working in
them, or if they are done in metric, it is simply a conversion of
English units of standard sizes, and not a true metric design.
Copies of passenger rail car design drawings obtained from the
manufacturer that I've used at work either are in customary units, or
have both metric and customary units.
> BTW, OUR US money is metric. Dollars are divided into 100 cents.
> Even Britain gave up the pounds/shillings/pence system decades
> ago. There were 12 shillings to a pound and 20 pence to a
> shilling. There were also odd coins such as half crowns (2
> shillings, sixpence - two and a half shillings).
The British system was the way it was because a "pound" was a pound
of silver like the Roman pondus, while a pence was 22 to 24 grains of
silver, and weighed the equivalent of 22 to 24 grain seeds of corn
(i.e. wheat or barley). A British pence was equivalent in weight to
half a debased Roman denarius, or twice a sestertius = half-pence.
The ratio of 1 to 240 in silverweight of silver pounds to silver
pence was set by Charlemange and King Offa around the same time.
The metric system has nothing do with our currency structure, nor is
everything that is decimalized metric. In fact, our currency was
adopted longer before metric existed.
We engineers work in decimal feet and inches and gallons all the
time, but obviously aren't using metric when we do so.
