Re: Frt car distribution...again: Was: Re: new books - Lack of Eastern SS Boxcars in LA during the Depression
Steve and Barb Hile
I think that the "theories" about car distribution really aren't intended to be applied to individual trains or, perhaps, even a given yard scene. Where they are most useful, in my opinion, is in selecting a population of cars to use on a given layout and its intended operation scheme. We hear regularly from members of this list who say that they are going to have 500, or some other number of cars and they then use the "theory" to select those cars that will make up that population.toggle quoted messageShow quoted text
From there, any of the operational programs can then simulate the individual trains with reasonable, prototypical appearance. Even the most basic single diorama with staging at either end can have reasonable looking trains traversing it with random or rule based consist generators. In fact, a rule based consist generator could be devised, based on the chosen prototype's basic schedule. For example, train 99, the east bound perishable could have rules that state that 70-80% of the cars must be ice reefers, while the westbound drag consist would have only 20-30% reefers (now empty), etc.
The above presumes that we are willing to do a fair amount of hand fiddling of the train consists prior to their appearance "on stage." To my mind, this is an acceptable small layout alternative to the detailed local switching, making up of trains in the yard, etc. that are possible with the larger layouts.
There is a problem if, like Mike, you want to be able to duplicate the extreme anomaly of 40 SP boxcars in a single UP train (or whatever.) The choice to be made is where to "bend" the theory in terms of the layout's car population. There is no argument that the train in question was far outside the "predicted" distribution. But the question is, really, would there be one of these consists on a regular basis in your period of interest? If the answer is yes, then the population must be "bent" to allow the consist generator to create that consist when appropriate.
There really isn't a good reason why the "national" distribution of certain car types shouldn't be used in conjunction with anecdotal information, such as movies, photographs and individual train lists and knowledge of scheduled freight trains, including their blocking scheme to create realist and believable, and therefore ultimately satisfying, consists for our model freight trains.
To me it is not an either/or situation. It is better to use every tool.
----- Original Message -----
From: Mike Brock
Sent: Saturday, September 23, 2006 11:20 PM
Subject: [STMFC] Frt car distribution...again: Was: Re: new books - Lack of Eastern SS Boxcars in LA during the Depression
Jeff Aley asked:
> > Huh? I thought that Mssrs. Nelson and Gilbert used wheel reports
> > otherwise: that at any major point in the U.S., boxcars are
> > according to their national percentage.
Well...I don't think tim Gilbert is saying that. The time element has to be
considered. IOW, at any major point we don't have a clue what the population
of frt cars was or should be at a particular time. It MAY be that over a
relatively long period of time...say, a year...the wheel reports suggest the
Nelson/Gilbert theory might be a useful predictor. However, we DO know that,
in 1949, the theory fails with regard to the UP mainline across Wyoming
using information from the infamous 34 UP frt trains. As anyone who has been
a member of the STMFC for a year is painfully aware, the number of SP and
CB&Q box cars in those trains exceeds their national average considerably.
Why this is so doesn't really matter. We are more interested in the way
things were since we are interested in reproducing them. I might add that
movie photography is not an example of shooting an interesting frt car...at
least as seen in the Big Boy Collection which shows entire UP frt trains
rather than a particular car or group of cars. And, those frt trains
definitely violate the population predictor. What we do know from the
population studies is that a RR's box cars went all over the nation whereas
other types of cars, particularly coal carrying cars, tended to be more
regional in distribution. Stock cars and gondolas [ and the pronounciation
of the term doesn't seem THAT important ] seem to be more nationally
distributed as well. Now...if you wish to monitor your layout's op sessions
on a yearly basis, the population predictor might be very useful.