Malcolm Laughlin <mlaughlinnyc@...>
Posted by: "John Stokes" >This is the other factor in this essentially impossible and largely meaningless exercise in trying to figure out how many cars of each type would typically be seen on a train in the time period selected and then extrapolate that information to one's model railroad.
Agreed. The whole exercise is meaningless because it's all predicated on the equal percentage of all ownerships on all railraods, a totally unwarranted assumption. If I looked at a model railroad situated in California and saw percentages of FEC, CGA, B&M, RDG, RF&P cars that were not a lot less than SP, WP, SP&S and other westen marks percentages of the national fleet, I would know he's not really modeling the region, but wants to give eastern cars equl weight.
Reality is not the same as a computer simulation under the rather limited and primitive conditions we are working in here. It doesn't take a long time looking at photos, for example, of Northern Pacific or Great Northern freight trains and yards to see that at least on the days the pictures were taken, home road equipment often dominated, but the stats say otherwise. Go figure. Glad you are having fun with all this, Mike.Using computers, you can get all sorts of detailed calculations based on data and assumptions that are wrong. Unless you are sure of the assumptions, those calculations are useless. I say this as one who believes in computer models and has used them at various time since 1966. But it's a total waste if the initial data assumptions are invalid, which I say is the case for all of those Excel calculations.
Malcolm Laughlin, Editor 617-489-4383
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