obsolete units of measure (Saxon and railroad)

[Catlady (Rita Prince Winston)]

Geoff wrote in
<http://groups.yahoo.com/group/HPFGU-OTChatter/message/38714>:

<< 
12 inches = 1 foot
3 feet = 1 yard
5280 feet = 1760 yards = 1 mile 
22 yards = 1 chain
10 chains = 1 furlong
8 furlongs = 1 mile

A rod is 5.5 yards, hence four to the furlong.
>>

This stuff (rod and chains) always makes my brain hurt. The rod is an
old Saxon measurement IIRc originally called the gryd, but IIRC the
chain was invented in the 18th century by some surveyor -- it was
literally a chain with each link one inch. If only he had named it the
'staff', perhaps this stuff would comfort me instead.

I think we agree on the length of the furlong (8 to the mile = 660
feet = 220 yards) and the chain (10 to the furlong = 66 feet = 22 yards). 

I think we agree on the LENGTH of the rod (you said 5.5 yards, and I
had worked it out as 16.5 feet as 5280 feet (mile) / 8 = 660 feet
(furlong) divided by 10 = 66 feet (chain) / 4 = 16.5 feet (rod).

But four of *my* 16.5 foot rods add up to 66 feet, which is one chain
rather than one furlong.

The original point of my post was that an acre, the amount of land
that one Saxon can plow in one day, is one furlong times IIRC 4 rods
which is 10 rods times 4 rods = 40 square rods, and slightly more
usefully, 660 feet * 66 feet = 43,560 square feet. The foot 'acre'
comes from the same root as 'agriculture'. I wonder how far apart the
furrows were i.e. how many furrows to an acre.

I got on Google and studied all this stuff a few years ago because I
was assigned to a project to create an electronic catalog of all the
assets for which Maintenance of Way was responsible. Part of the
catalog had to be the asset's location.

Manfred, the user assigned to be our liason, insisted that locations
in the Right of Way were identified by "chaining". I managed to get a
map from him of how Blue Line MOS (Minimum Operable Segment) 1 was
assigned to contracts, which had the locations in chaining (X + Y,
where X is an integer and Y is a decimal number, like "353 + 12.25").
He explained that X is the number of chains + Y is the number of feet
from some mark point, but denied knowing how long a chain is. He said
he thought it might be 66 yards.

Google revealed that a chain can be 66 feet, 100 feet, or 1oo meters
depending on whose chain it is. Also that 'hundredweight' can weight
160 ('long'), 120 ('short'), or 100 ('American') pounds or 100 kilo
('metric'). I remain very much struck by this lack of agreement of
meaning.

I got a sample map from Safety as part of required rail safety
training, which was marked in feet, and one station was on both
Safety's map and Manfred's map. Comparison between them revealed that
Blue Line's MOS-1's chain is 100 feet. They could have replaced the
"+" by multiplying times 100, like "35,312.25". 

Not that that would have done any good, as each contractor had used
their own mark point to begin the count, so at the exact same point,
the 'chaining' of the track was a totally different number than the
'chaining' of the catenary (the overhead copper cable that carries
electricity to the rail cars), and at least one of them had done his
counting in the OPPOSITE direction of everyone else. So, y'know, not
only could the same point be identified by several different
chainings, the same chaining could identify several different points.

The best I was able to do for identifying the location of assets was,
if they were in a station, I could specify the station number and room
code. If they were between stations, I could specify which two
stations they were between. I kind of screwed this up because I
started with the Red Line, whose railyard was at one end of the line,
and didn't realise that the other lines' railyards were *beside* the
main line somewhere, with a bunch of track to get cars from the
railyard to the main line and back.