I bought the Chooch O scale kit for the CP 30' dominion boxcar first, and then did some research. The Paul Clegg articles in the June and July 1985 issues of Mainline Modeler seem to indicate that very few of these cars were converted to AB brakes. I believe that this means that they could not be used in US interchange service after August 1953.
Does anyone have in-service photos of these cars taken in the US in the early 1950s?