The Glengyle is the earliest known survivor of the fleet of heavyweight, all-steel sleepers built by Pullman Company. The design was introduced in 1907 as a marked improvement over the wooden version then in use. Some 10,000 were built, in various configurations, the last in 1931. The Glengyle is original in its interior and most of its components.

George M. Pullman (1831-1897) built and operated sleeping, lounge, and parlor cars beginning in 1859. While not originating new inventions, Pullman often adopted new technology, making his cars mechanically well-engineered structures. He was one of the first to use the enclosed vestibule and diaphragm between cars, the Westinghouse air brake, Janney knuckle couplers, steam heating, Pintsch gas lamps, and electric lighting.

Pullman's first all-steel car, the Jamestown, was built in 1907. It proved the merits of steel construction, but was overweight. Additional work resulted in a lighter, improved car structure. Production began in January 1910 with a car named Carnegie, and continued, using the same basic design, for the next two decades. This standard car structure also allowed Pullman to standardize various mechanical systems, resulting in improved reliability in addition to the greater strength and safety of the steel cars.

The Glengyle was constructed during the first year of steel-car production and was initially assigned to the top New York-Florida trains. The Glengyle is also one of the first sleepers to contain only enclosed rooms, rather than the more common open sections. All-room design did not become commonplace until the late 1930s. At the end of their service, many of these heavyweight Pullman cars were converted to tourist sleeper or baggage cars, and most were eventually scrapped. The Glengyle, which remained in service in its original configuration until 1957, escaped this fate when sold to the Lone Star Steel Company in Texas, which later donated it to the Southwest Railroad Historical Society in Dallas.