Mike

That's a lot of betting, doubts, and exclamatory statements for one
paragraph. Since when does a "shorter route" have much to do with
anything related to car routing? Freight cars don't travel according to
the "shortest route" logic -- they return by the way they came, unless
they don't, which in a great many cases, is what happens. I'm very
confident that UP carried SP box cars west over Sherman Hill to
all kinds of destinations not on the SP. And likewise SP forwarded
UP box cars to the Rio Grande for delivery to who knows where?
And what does it mean anyway?

You have the advantage of modeling Sherman Hill, basically a
pure east-west traffic pattern that prevailed for hundreds of miles
to the west, and relatively little north-south activity in that area. But
to extrapolate from Sherman Hill to Columbus Ohio, practically in
the epicenter of a couple of dozen overlapping railroads radiating
in every direction from scores of junction points and interchanges
within a 100 mile radius?? Are you kidding? I'm never quite sure as
you seem to enjoy baiting us ... and you got me to rise to the occasion.

But I'm still not sure what you were driving at, unless you're trying to
say that on Sherman Hill, SP box cars were proportionally more
common than other railroads not so closely affiliated with the UP.
And to that, I agree, since I've said before that the Overland Route
was practically a joint operation of the two railroads during this era.
But other than the percentages, I doubt there are many useful
generalizations anyone can make about what those box cars were
doing (Empty? Loaded? Eastbound? Westbound? Bridge traffic?
Received to terminate online? Originated to end offline?)

Tim O'Connor