Richard Hendrickson wrote

There is some evidence that Santa Fe tank cars occasionally
went off-line at other times, as well.

Isn't it true that for a railroad owned tank car to go off
line with a load, there would have to be to a published
common-carrier tariff for that load and origin and destination?
Since most liquid loads travelled in leased tank cars, am I right
to assume these did not travel on common-carrier tariffs but were
handled under "private car" rules (mileage, etc)? I guess what
I'm getting at is, if there were common-carrier tariffs for
tank car commodities, then there would be a paper trail that
would tell us what travelled in RR tank cars and where it went
to and from. (I can't recall seeing any pictures of SP tank cars
off line either.)

Tim O'Connor