Re: Freight car Distribution

Wendye Ware

--- In STMFC@..., "Aley, Jeff A" <Jeff.A.Aley@...> wrote:

Out of 1042 box and auto cars in the Traud 1951 book (see<> ) ,
there are 72 SP cars and 4 WP cars, or 6.9% and 0.4%, respectively.

The 1950 ORER spreadsheet recently posted on STMFC shows the SP had 3.8% of the national fleet, and WP had 0.3%.

This data tells me two things:

1) The WP is not under-represented as I had previously guessed. [Translation: I was wrong!]

2) The SP is over-represented, compared to its portion of the national fleet.

Both of these data points appear to be in agreement with the G-N model, which accounts for the increased presence of "connecting roads". One does have to know that SP needs to be considered a "connecting road", while the business relationships of the WP-DRGW make the WP-UP connection a "normal" connection, without an increase in cars beyond the proportion in the national fleet.


Hi Jeff, et al.

Here is some more info about SP & WP cars in UP trains in Wyoming between Laramie and Rawlins. The data is from a Freight Conductors' Train Book compiled by Conductor Fitz from September 16, 1938 to October 24, 1938, and previously summarized in post #85454 on this list. Fitz recorded the car type for all but 58 of the 2,362 cars in his book; 742 of them were box or auto cars, and of them 62 (8.4%) were from the SP and 18 (2.4%) were from the WP. These compare to national totals and percentages of box, auto, and ventilated cars (U.S. only) in the January 1938 ORER as follows:

Road: #cars; percentage
SP: 24,398; 3.2%
WP: 3,141; 0.4%
US: 764,080; 100%

So in this 1938 train book the SP had over 2.6 times as many box and auto cars as it "should" have had, and the WP had 6 times its share.

Similar results are found in the Ferguson and Fraley train books, I believe, but their analysis is hampered by the conductors' reporting of the car type for less than half of their cars. The raw numbers seem consistent with Fitz's data however:

Road, Conductor, # (all) cars
SP, Fitz, 64 (62 box/auto) (Sept-Oct, 1938)
WP, Fitz, 18
Total, Fitz, 2362

SP, Ferguson, 101 (May-June, 1938)
WP, Ferguson, 25
Total, Ferguson, 2788

SP, Fraley, 45 (Sept-Oct, 1938)
WP, Fraley, 11
Total, Fraley, 2510

In each of the 1938 train books (all from the Laramie/Rawlins run on the UP), the WP has about one-fourth as many cars as the SP, whereas it "should" have only one-eighth. The SP is certainly over-represented, but the WP is over-represented in spades!

Best wishes,
Larry Ostresh
Laramie, Wyoming

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