Jim Pattison in MossyRock,
It is easy to take "prototypical accuracy" too far - far enough that others may not
even notice and probably don't care ... one of the costs of ultra high prototypical
accuracy is the time it takes to do the research, build/modify the models, etc.
If "that's your thing" then by all means Go For It.
All of the "formulas for freight car mixes" that I've seen have been very good - but also
they usually use a relatively small data sample - even a sample as big as "all of the
trains passing one location in the month of April of '53" are "relatively small". Same
thing for using the ORER numbers.
Before anyone gets their panties in a twist - I am -NOT- saying that those formulas
are wrong. And I'm not saying ignore them and totally do what you want. I'm saying
that compared to the number of cars "on the SP Coast line in the years between
_____ and _____ it is a small sample.
What I'm doing is using those formulas to -adjust- my freight car fleet - but not to
-define- it and most certainly not to build up the consists of the trains I'll run on my
The result of my approach is that if you inventoried the cars in my fleet you'd say
"pretty close" - but if you tried to apply those formulas to an individual train you'd
say "well, not so much".
My layout is a "switching layout" based upon an isolated segment of the country
and in a specific era (PNW, Skagit County, GN, and 1946-1955). And I have
-chosen- to fudge and run far more steam than the GN did in those years
(because I love steam more than diesels).
If an individual train is "believable" then I am happy. If all of the trains on my
layout are "believable" (one at a time) then I am happy. If they aren't believable
in the aggregate ... I quite frankly don't care. ("It's my RR ..."). I'm focusing on
the Op itself and the layout second and the prototypical accuracy a distant 3rd.
YMMV and that's fine with me.
Perhaps the real wisdom is simply to get away from the bright shiny object
syndrome and make an attempt to be more prototypical. If that's your thing ...
- Jim (also in the PNW)