When the NYC Pacemaker b ox cars first went into service, they did not have the full AAR data on them required for interchange. Only the Load Limit and Light Weight were shown below the car number. The were in captive, on-line service. Within a few years the red and gray Pacemakers were released for interchange. In so doing, they usually got black (instead of the original white) reporting marks with full data for capacity, weigh station, date, cubic footage and car dimensions. In that form, a NYC Pacemaker box car could show up in SoCal, as could a B&O blue and sliver Sentinel car, which had full data on them when new.
The B&O blue with the orange comet "Time Saver" service cars were very few in number. The B&O Group when on Yahoo could only identify nine such cars from photos. None had sequential numbers and some sported a different roof color. These cars did not seem to last long in that livery, suggesting B&O did them up for advertising at special events such as state fairs in its service territory. When shopped, they were repainted in the standard freight livery. Sentinels were maintained with blue and silver until the early 1950's, when B&O ordered that this paint job was no longer to be used and such cars when shopped were to be repainted in standard oxide red. A few cars not needing heavy repairs kept their Sentinel blue and silver into the late 1950's.