These fully assembled HO Scale cars feature scale dimensions and rivet details, factory-installed side door handrails, full detailed interiors, complete end, underbody and roof detail, scale set-back windows, working diaphragms, car name and number decals, correct trucks with RP-25 metal wheels for each car, factory-installed electrical pickups, removable roof with air conditioning ducts, working McHenry knuckle couplers and swinging drawbars to improve curve performance.

While Pullman favored open section cars, travelers came to prefer private accommodations. This led to the 6-3 all-room sleeper, with six compartments and three drawing rooms. These cars were easily identified by the odd window arrangements on each side; one had 12 single windows spaced some distance apart, the other had paired windows placed close together. Popular on long-distance trains, 203 of the cars were built as Pullman Plan #3523 (cars from Lot #6152/6341 are the prototype for this model) from 1923-26. Air conditioning was added in the early 30s and some were still in service into the 1960s.