Built in 1925 by the Pullman Manufacturing Company as a passenger car, Norfolk Southern Research Car 31, also known as Pullman Car 2483 and Southern R-21, was converted by Southern Railway in the mid-1960s into a track geometry car, or track recording car. Likely renumbered after Southern Railway merged with Norfolk & Western Railway to create Norfolk Southern, it became part of the rail safety work of researching and monitoring track strength and stability. Onboard computers calculated track width, rail wear, track curves, and other measurements, and the car's primary function was to measure rail wear and track gauge. Half of the car was used for research, while the other half contained crew living quarters including a kitchen, dining area, and pull down sleeping berths. Converted in Southern Railway's Haynes Shop in Spartanburg, North Carolina, it was an early self-contained track geometry car with sensing and measuring instruments, data recording equipment, a power unit, and extra weight to deflect the track. The extra weight caused cracking in the wheel frames, and the car was replaced by Norfolk Southern Research Cars 33 and 34. In 2007, the car was loaned back to Norfolk Southern, which updated it with new equipment such as lasers and used it to test railroad tracks for two years before returning it to the Virginia Museum of Transportation.