Mike Brock <brockm@...>
Gene Green writes:
"All this discussion of freight car distribution has what purpose? A
purpose does not seem self-evident to me."
A very legitimate and timely question.
OK...here's an opinion...and it seems obvious. The data developed by Dave Nelson and Tim Gilbert have resulted in a theory that the % of a foreign RR's box cars on a given RR will match the % of the foreign RR's % of the national box car fleet. Tim noted:
"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."
Tim was responding to a comment that I made that my op sessions always replicate May 14, 1953. While I did say that, it was tongue in cheek...I actually simulate the entire month of May, 1953. But his point was, I think, that the theory could predict and, therefore, project the foreign box car population over a relatively long period of time...I think a year was suggested. The problem with this concept is that frt train consists, at least on the UP in Wyoming, were very variable. IOW, 30% of one train might be UP box cars while another might have no UP box cars although 50% of the train was box cars. About 8% of the box cars should be UP [ home road % of about twice the national % ]. As I pointed out, major RRs interchanging with a RR...at least in UP's case...seem to be more represented than that of the national %...as in the case of SP. The problem is, even with compression of model train lengths and compression of the number of trains present during an op session, the need to have enough cars to match a particular train...like the lumber trains with 31 SP box cars in 1949...means that a rather large car base would be required...in this case, at least 1000 box cars IF that base reflected the national per centages. So...what does one do? Well, I for one recognize that the value of the theory and statistical data is that it shows that box cars went everywhere. The numbers of different foreign box cars on a given layout probably reflect the RR being modeled. IOW, there might be a "local" factor at work as in the case of UP and Milw, CB&Q, C&NW and certainly SP and I would have more of them than the theory calls for....probably calling for 1.5 times the national %. Why? I don't care. It's just the way it was. At the same time if I wanted to simulate a particular train...compressed...I would simply have enough of those cars available as well and I wouldn't be concerned that the total box car fleet would not reflect the national per centages. IOW, my box car fleet probably won't exceed 150 cars[ hmmm...guess I'll have to count ] .
I realize that we have a great deal more information about UP in Wyoming than might be available for other RRs and what applies for the UP trunk line across WY might not apply to other areas. After all, everyone knows that at least one of every class of frt car went over Sherman Hill at some time. Heck, even General Tojo went over Sherman Hill.