Re: Freight car Distribution- Larry Kline
--- In STMFC@..., Larry Kline <lndkline@...> wrote:
To my mind this is not that surprising. Your data provides another good confirmation of the N-G at the overall level, but as many have remarked here, there are reasons for local variations.
Do you have the data sorted by direction?
As the PRR and NYC were near mortal enemies, I still believe that an empty NYC box car in the eastern portion of the PRR system would be expeditiously sent home. Why pay THEM per diem, and why load a car for them?
I would think this would cause local deviations, for extended periods, from the expected N-G type distribution, at least in certain directions and at locations near an interchange.
The PRR was in the WM's backyard, and vice versa. It is not surprising to me that lots of PRR box cars were headed out from the PRR service territory on the WM to hit customers in the Western MD, Western VA, and West Virginia areas.
I view this as a funnel effect. As long as empties were headed home, and home roads had enough empties on hand to preferentially load their cars over immediately adjacent competitors (who's cars could quickly be sent home), it stands to reason that there is a funnel effect near each interchange point with that road. IN the extreme, at the actual point of interchange, it seems reasonable that a disproportionate number of MTYs will be delivered to the other road. Otherwise how could their cars get home? As an engineer, this is a simple continuity of mass equation.
This effect may be harder to notice for a small road - WM box cars were not that many such that a PRR railfan in Harrisburg might notice more of them than N-G would predict, but someone on the WM might think they were surrounded by the PRR - there fleet was so HUGE to begin with. (And they were at least partially surrounded!)
But this lack of NYC MTY's on the PRR would also lead to a dearth of NYC box cars heading south onto the WM. Any loaded NYC car destined for the same customers might take a very different route than a PRR loaded car (plus I do not think the NYC service territory had the quantity of industrial customers generating loads that the PRR had.)
When looking at PRR photos on the mainline west of Harrisburg, I am continuously struck by the tiny number of NYC boxcars heading WB. I think this is a similar local effect. Why would an MTY NYC box car in Harrisburg EVER be sent west. Since the westbound mainline PRR traffic had a significant percentage of MTY's, it stands to reason that NYC cars would be noticeably under-represented (there might still be some loads).