Re: A Purpose For Frt Car Distribution Studies.


Dave Nelson
 

-----Original Message-----
From: STMFC@... [mailto:STMFC@...] On Behalf Of Jim
Betz

I think it has been left unsaid that it is very common to go to an NP
layout and see far too many NP cars - or to a B&O layout and see almost
nothing but B&O cars. And when you look at a picture of a freight yard or
freight train "it just isn't so". The point is that some (many?) of us get
too wrapped up in our favorite railroad and tend to have way too many
freight cars for "our" railroad on our layouts.
------------------------------------

To be clear for everyone... The Distribution Hypothesis under discussion is
all about Foreign Road boxcars.

Home Road Boxcars is very different: One can find ICC data in the annual
Blue Books that cite, nationwide, the typical ratio of Home Road boxcars to
Foreign Road boxcars for the preceeding 10 years. Tim Gilbert took those
numbers and dug up when the recessions were and found there was a geneneral
trend that in recessions there were more Home Road boxcars on Home Rails
than there were in times of plenty.

I don't have the data right here in front of me... But IIRC in WWII Home
Road Boxcars on Home Rails were about 21-24% of all boxcars... The rest of
course were Foreign Road cars. In bad years the numbers might climb by
10-15 points.

In the absence of having the data at my fingertips, I would hazzard a guess
that 25-30% of your boxcars should be home road cars. If you want something
more precise, get a Blue Book and look it up.

Now I happened to do a lot of computer modeling of the Western Pacific
traffic... I won't bore you with the details and assumptions as there are
plenty of both to go with a handful of facts but from that modeling I
realized that it was quite likely the WP terminal in Oakland / San Francisco
area received about twice as many carloads as were shipped. Doesn't really
matter if that's really true... Just take it for now as a talking point.
So, if a particular area on a railroad had a much higher ratio of boxcar
receipts than boxcar shipments, it would stand to reason that the local
yardmaster (a) probably had little need for home road boxcars held in
protective service and (b) had to deal with getting a lot of empties out of
his yard. IOW, very few Home Road boxcars there. Conversly, if any area
has very few recipients relative to shippers, the local yardmaster (or
agent) probably had a considerable need to home road cars held in protective
service and so their numbers might well be higher than whatever road-wide
average might suggest.

So going back to the rough figure I cited above of 25-30% of your boxcars
should be home road. That really should be adjusted by your best estimate
of what the shipper / recipient boxcar ratio is -- both on the layout and
what would be adjacent areas. All the rest of the boxcars you own then get
addressed via the distribution idea under discussion here.

And again, I'm talking about plain Jane XM boxcars.

Dave Nelson

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