I picked this up at the recent Pandemonium at Timonium for a good price, mostly because Container Corporation of America had a plant on the Canton Railroad near Eastern Avenue next to 95, and I recall fondly watching them switch railboxes full of rolls of corrugated to their platform. But I never saw a car with their own markings on them.

A quick Google search for several variants of "CCA Boxcar" netted me some model photos, including several scales and Lionel, but nothing in the way of a prototype car. Curious as to the era they may have run, and whether or not they existed at all... The markings indicate a build date of 3-63, so it works with my mid 60s time frame.
Where's Puddington when we need him most!!
Lee