A Purpose For Frt Car Distribution Studies


Tim O'Connor
 

Steve, I don't see any 'danger' at all, as long as you
-ASSIGN- cars to run on the layout in the proportions to the
national fleet. In other words, suppose you have 103 box cars
and Railroad XYZ only represents 1 as a national percentage,
but you own 4 XYZ box cars. No problem -- in your computation
(like Larry's EXCEL spreadsheet) you only allow each XYZ car
to represent 0.25 (1/4) of one car.

This gives you the ability to model more of the fleets of
your favorite railroads, but has no effect on the proportions
of those cars that show up during operations.

As for the percentage of 40' vs 50', I don't see any issue.
If you need a higher percentage of 40' cars then build your
fleet that way. The numbers of cars for a typical layout are
too small to give a true proportional representation of the
entire country. You'd need about 1,000+ box cars to do that.

Tim O'Connor

The danger lies in having a model car fleet that models many
exceptional cars, rather than a good overall representation of the
national fleet. But it's too easy for the modeller to, absent
knowledge of each road's freight car fleet and its relative
percentage to the national fleet, to model those exceptions. For
example, as much as I want a model of a B&O M-53, there are other B&O
cars that I have come to learn to be more common to that road. I
have to have many CN boxcars (fortunately, I do) to justify modelling
just ONE of the three aluminum-sided cars that they had. If you model
20 B&O boxcars, you can justify having one M53 in your fleet far
sooner than I can, where I will only need one B&O boxcar for my
layout.

Likewise there is some weighting that one has to be factored in by
the modeller to represent the location that they model. Your road
may move a lot of grain in boxcars, and the ratio of cars (home road
vs. national fleet) will change whether or not the grain is running.
Likewise, boxcar precentages from the ORER are not a good way to
determine the car population for a grain-hauling layout. Preferred
will be 40' steel or steel-frame boxcars with 6' doors. Far less
common will be cars with larger doors, as they were practically
useless for grain loading. And open coal hoppers, though not part of
this discussion, will have interesting distribution variations of
their own!

Steve Lucas.