Re: Numbers/percentages of important box car types

Tim Gilbert <tgilbert@...>

Tony Thompson wrote:

Dave Nelson wrote:
Most conductor's logs will contain more than 25 trains. Tim and I have
looked at several thousand boxcar entries from hundreds of trains.
give a clear and unambigous body of data that shows those railroads
with the
most boxcars (e.g., PRR, NYC) have their cars recorded most often and
with the least, least often, with everybody else in between, generally
falling in line by the size of their boxcar fleet.
I am convinced by these data for the overall national behavior.
But if anything, these combined data will OBSCURE local differences
with particular trains. Tim O'Connor has made this point: the modeler
wonders if a PARTICULAR train exhibits the overall averages.
Statistically and in common sense, the answer must be NO. To some
extent, that's what Mike Brock is saying.
You can't have it both ways: the bigger the sample, the less
information about particular trains. That solves some problems, sure,
but obscures others.

I agree with you in terms of a "fixed" consist in a specific freight train a la the "California Zephyr." Mike Brock seems to have been trying to "California Zephyrize" his freight trains which infers running the same consist every time he operates his railroad. Freight train consists in specific trains, however, in the real world were different every day.

The freight car data which Dave Nelson & I have parsed from wheel reports and other car reports will not solve Mike Brock's "California Zephyr" problems. All they represent is a pool of cars which were reported by a railroad over a course of time.

The boxcar pools of each report are the subject of this thread. Both Dave & I have found that there is a correlation between the distribution of ownership of boxcars of those in each of the wheel reports and the percentage that the boxcar owner owned of the national boxcar fleet. Sometimes that correlation is good - and sometimes not so good.

Thus, the rule of thumb which infers in the absence of any other data to the contrary, the distribution of ownership among all the boxcars on a model railroad should roughly parallel the percentage that the owner owned of the national boxcar fleet. The Boxcars chosen would represent the pool of boxcars which individual trains haul. There is an element of selective compression in freight cars, too. There is no way to have all 700,000 plus boxcars on any layout.

Some of the smaller roads may not be represented on a layout limited to 100 boxcars. In 1947, roughly 84% of the national boxcar fleet was owned by some 28 RR's having more than 1% of the national boxcar fleet. How to allocate the remaining 16% among the 100-odd other RR's can become a problem.

If the model is designed to make pick-ups and drops, the consists of the freight trains should change each operating session. If there are no pick ups or drops on the model RR, then a bit of 0-5-0 switching will have to be done in staging. That does not mean that the percentages should be locked in, but adjustments should be made when better information becomes available.

For instance, both Dave & I have found that the total number of home road boxcars reported in a wheel report exceed by quite a bit the percentage of home road boxcars of the total US boxcar fleet. Canadian boxcars in the US are tough to get a handle on because of the Custom restrictions to their free movement in getting reloads when they are empty. OK, in these cases, home road & Canadian boxcars should be removed from the equation and "dealt by hand."

Sometimes, one or a group of roads owned much more boxcars in a report than their percentage of the national boxcar fleet. Mike Brock found that the number of SP Pacific Line boxcars were such a case in the Spring 1949 UP Conductor Fraley's Wheel Report between Laramie & Rawlins WY. No such aberration showed up in Fraley's Fall 1947 Wheel Report where the number of SP - Pacific Lines boxcars exceeded their percentage of the national boxcar fleet only slightly. I attempted to answer this in my comparative analysis of the two wheel reports in the STMFC message #51085 of 2/3/2006.

The answer of why could be focused around the question "How did the SP supply empty cars for lumber loading?" In the Fall of 1947, there was a shortage of boxcars caused by a severe boxcar shortage caused, in part, by the effect of the Grain Rush "back east" as well as a booming economy. In the Spring of 1949, there was no Grain Rush plus the Economy was in Recession. This downturn allowed the SP (& UP) to stockpile its own boxcars for lumber loading, and send home many empty foreign boxcars from Southern California home across Sherman Hill instead of diverting them to Northern California or the Pacific Northwest for lumber loading.

Which was "more normal" - Fraley's Fall 1947 or his Spring 1949 Report? Mike has chosen May 1954 as the date of his layout - 1954 being another Recession year. If I was Mike, I would give precedence to the Fall 1949 Report. If the date was the Fall of 1955 or 1956, I would give precedence to the Fall 1947 Report.

Tim Gilbert

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