They were one of the car types used by the Santa Fe to handle express traffic on lesser passenger trains, up to the late-60s. While I can't speak for the accuracy of the Atlas car (at least not without some photos to compare... probably best left to ATSF modelers) express traffic was a very lucrative service, so much so that, when this traffic was lost when Railway Express Agency decided to ship by truck and plane that several railroads almost immediately filed for, and received, permission to abandon passenger service while a number of others succeeded in gaining train discontinuations. Think of it as today's UPS by rail... a very profitable operation.
