On Jan 30, 2012, at 8:09 PM, Rob wrote:

I've been searching for a bit now and I haven't been able to find a
conclusive answer as to whether all of the 1942 AAR box cars for
Santa Fe and CNW/CMO have the shortened "darts" between the top two
ribs.

Ive looked at a few Bx-37 pictures that I have as well as a some
CNW cars but most don't have a clear end view. I haven't been able
to dig up a clear view of a Bx-43 to see if it too is the smaller
dart.

Rob, both the Santa Fe Bx-37 class and the Bx-43 class had the
slightly shorter top main rib and darts. And the photos I have of
the C&NW's '42 AAR alternate standard box cars show them with the
slightly shorter top rib, but the top darts are the same as the others.

Richard Hendrickson