Also, why do the cars in the rearmost track seem so much
bigger than the ones in front? (Example, GFX 10236 vs.
NP 8885 or NP 14368 vs. NP 35200) Were the reefers
really bigger or is this an optical illusion from the
photography technique?



It's likely a result of the use of a cut film camera with a
slightly wide angle lens. With "Wide angle" [a focal
length less than the film negative diagonal - very gross
rule of thumb] lens the so-called "wide angle" effect is that
objects in the foreground seem closer than they are,
and larger than they are relative to other objects.

The counterpart is the "Telescopic effect" which has
an opposite image effect, plus the more easily noticed
"compression" effect for distant portions of the image.

For a most pleasing effect, many "standard" and
non-interchangeable lenses are of a focal length to
be "slightly" wide angle. This can be noticed in many of
the freight car images (Mandatory STMFC content) that
are so often referenced on this list.

Mal Houck