Constructs like these were in place near numerous railroad stations in the U.S. This model is based on a photograph of one such 'catcher' at the Pennsylvania Railroad's Lewistown PA station. When a train was not stopping at the station, but there were one or more bags of mail for that community, the postal workers in the RPO car could drop the bag(s) out the door onto the 'catcher' as the train went by.