Re: Box/auto distribution 1938


Mike Brock <brockm@...>
 

Tim O'Connor writes:



Larry, does 2,267 box cars on the UP mainline even represent the
traffic of a single typical day? So here we are looking at freight
trains spread over four months... or on any given day, less than
1% of the box cars on the main line are sampled.

What can be learned from this? Nothing, I believe.
On the contrary, I think we know a great deal. We know what UP frt trains looked like. From my conductor's book, we know what 34 trains looked like. Not in a given day, but over about a month. Does this tell us very much about the total traffic over a month? No. OTOH, does knowing that help much with modeling a RR or part of it? No. Modeling frt trains requires information about frt trains and from the conductor's books we know that such trains were not just randomly put together from the available pool of cars...as would be the case if we just used the G-N. So, it all depends upon one's objective.

Look at it another way -- suppose you had conductors books for the
same time period from three other conductors. Do you think that the
tallies would be the same? I don't -- not one chance in a thousand.
Well...not the same but I believe that you would see similar trains. If you had all of the UP conductor's books for a couple of weeks you would discern unique trains consisting of similar consists...some running daily. Even in my 34 trains, it is easy to see similar trains. For example, reefer blocks, lumber trains, tank car trains [ both MTY & loaded from Sinclair ], stock trains, coal trains and even merchandise trains. The cars will be different but there were specific trains running almost daily...Roseville Fruit for example. And, while cars are different, except with merchandise trains, it is common to see cars of the same class in the same type of train. Hence, UP H-70-1's in different coal trains, PFE reefers, S-40-12 stock cars, etc.

If you had ALL of the conductors books for every day for a full
week, now that would be interesting! That would smooth out a lot
of the daily fluctuations. Of course there's seasonal variations,
but that might actually be easy to discern in a large sample.
But the daily fluctuations are the goal...if one wants to model real trains. Again, there were specific trains with specific tasks and, yes, sometimes they were combined. If one wants to simply know what frt cars operated between two points...like between Laramie and Rawlins...over a long period, you would need a large % of the conductor books for that period.

Mike Brock

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