Re: freight car distribution - rejecting the equal distribution hypothesis.

Malcolm Laughlin <mlaughlinnyc@...>
 

It has been stated that the burden of proof is on me that box cars
were not distributed on all railroads in proportion to ownership.
The burden of proof notion is not applicable here because it is not
possible to "prove" either side of the argument, which could be done
only if car accounting records from the period were available.
Absent any method of proof, we have to fall back on logic based on
known practices and traffic flows at the time.

Here are some variables that work against proportional distribution
across all railroads.

- Car service rules. While we know that car service rules were not
always observed, we also know that many railroads did observe them
most of the time. This greatly reduces the likelihood of an FEC car
in Oregon or a WP car in Maine.

- Length of haul. I believe that the average length of haul of a
carload was in the area of 300 to 500 miles. This was for all car
types and probably unknowable by specific type. Given our known
bias, of undeterminable magnitude, toward loading in home road cars,
the probability of seeing any mark on any railroad is biased downward
by its distance from the owner.

- Seasonal tides – the grain harvest for example. Nationwide there
was a fixed fleet of cars usable for grain loading. The big Midwest
harvest began in Oklahoma and nearby areas and over the course of a
few months moved north to the Dakotas. The car fleet moved north
also, quite inconsistent with the proportional distribution
hypothesis. The AAR issued movement orders to get cars from the east
to grain loading areas was another source of bias.

- Surpluses and shortages. They varied widely by season, region and
type of load. The largest 40 ft. narrow door box car shortage crises
were in the best grain crop years. When the shortage was over, many
cars went home to rest for a few months. A peak grain harvest in a
time of business recession would really skew the distribution.

- Suitability for loading. Some cars were more suited for paper
loading, others for grain, BCK cars for flour, etc. Locations of
large users of newsprint strongly biased the destination areas of
cars with marks of the paper loading railroads. Railroads serving
lumber producers a much higher proportion of cars dimensionally
suitable for lumber. The multitude of such situations caused many
pockets of ownership concentration.

- Cars out of service. On the NYC we had thousands of XM box cars
out of service awaiting rebuilding or rarely used because of
obsolescence. The proportion of such cars varied widely among
railroads. As a result the listings in the ORER was only
approximately representative of the cars actually hauling freight.

I could probably think of other factors given some time, but I think
this is enough to say that the equal distribution hypothesis requires
a huge leap of faith. Remember that it is a theory developed in a
quest to answer a question that may not be answerable and uses data
that is only indirectly related to the end result and purportedly
validated by a very small sample. When statistical results vary
widely from what our knowledge of the real world leads us to expect,
we should first question the validity of the statistical method.

BTW, that storage to shortage phenomenon is a reason that average
loads per car per year gives us no useful information about
turnaround time of cars actually in use. And it didn't mean that
long tracks of stored cars. That surplus was distributed a day or
two at a time over thousands of yards and stations - cars awaiting
distribution for a day or two more than they would have in a time of
shortage.

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