The Interchange series contains articles about railroads that interchanged with the Pennsy, including fleet statistics and paint schemes with era-appropriateness guidance. A few noteworthy or pertinent freelance model railroads are included.
As of 1954, the PRR's "Makeup of Trains" consist books list show only PRR reefers used in the creation of passenger trains. With few exceptions, class R50b is prescribed. Videos and photos, however, show Railway Express Agency reefers in use as well, though to a lesser extent.
The following table was created from data contained in The Official Railway Equipment Register.