Re: Freight car distribution

Tim O'Connor

Mike Brock wrote

Larry, could you explain what you are talking about? You show RR [ i.e., SP
excluding T&NO ], number [ number of SP box cars { 27757 } ] Nat'l % [ you
show 4.0% but Tim shoed 3.9% ] and Random % [ 4.01% ]. What is the
derivation of the random %?
Mike, he ran 100,000 iterations of a 40 car box car train, composed
of cars chosen randomly from every possible prototype. The National
% is obvious, and then he finds the AVERAGE % found for that railroad

I tallied the maximum number of cars for each railroad over all the
iterations. In a 40 boxcar train, the average number of cars would be
40 times the national percentage shown in the above table."
Why do you say that?
Because he described it obscurely. He simply kept track of the largest
number of cars seen for each reporting mark in the 100,000 trains. Is
this not also obvious?

Well...actually that's not so at all. The correct number is 4. 136/34
If you use real...rather than theoretical data.
Real what? 136 box cars? 136 trains? 136 days? 136 train consists?

Larry's example was PURELY theoretical, and he made an excellent point.
I guess some people just don't get it.

We know that there were 4 of 34 trains...11.76%...of the trains with
far more than 9 SP bx cars.
Mike, you are having trouble grasping the idea. Larry has presented
100,00 theoretical trains, of fixed length, of random composition.
You persist with your miniscule sample of 34 actual trains of
varying length and composition of different sorts of cars (not just
box cars).

The 1953 data shows the "infamous" train with 36 or more SP box cars
[not T&NO ].
Yes, but I will argue that the Overland Route for the UP and SP was
a 'home road extension' in that each road was highly dependent on the
other for traffic. Therefore we can discount the presence of SP as
well as UP cars in all trains over Sherman Hill, for the purposes of
this discussion. This is exactly the "skew" that each layout has to
consider.

Tim O'Connor

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