Wikipedia
Pine-series (railcar)
The Pine-series was a fleet of sleeping cars built by Pullman-Standard in 1953. The cars were built according to Pullman plan 4183; each contained six sections, six roomettes and four double bedrooms (colloquially "6-6-4"). The cars were originally owned by the Louisville and Nashville Railroad (L&N), the Chicago and Eastern Illinois Railroad (C&EI), and the Nashville, Chattanooga and St. Louis Railway (NC&StL).