Freight Car Prototypes
1937 AAR Box Car

The 1937 AAR box car and its subsequent iterations represent the first voluntary and mass adoption of a box car design by the railroads. While the USRA designs were certainly ubiquitous in their distribution, they were also mandatory designs, as the government forced the railroads to accept these designs. After government control was lifted, the railroads returned to the construction of designs that suited their own individual tastes. While the ARA designs of the 1920’s and 1932 resulted in some standardization, they were also plagued by regionalization (the X-29/1923 ARA box cars gained widespread adoption in the industrial Northeast) or significant modification (the 1932 ARA box car featured seemingly limitless combinations of roofs, ends, doors and underframes on a basic set of car sides. The 1937 design experienced widespread adoption in all areas of the country and the number of variations to the design was quite limited. While the purpose of this part of the site is not to engage in a lengthy debate about the reasons for this adoption, it would be interesting to know if the railroads succumbed to standardization because of its inherent cost advantages in a time of economic uncertainty (the mid-to-late 1930’s). The number of cars constructed to the design seems to indicate that the railroads were quite accepting of the experiment. The standardization that the 1937 AAR design introduced and its acceptance by the railroads ushered in the era of standardized equipment.

The table of prototypes is a living document. If you see a mistake or an omission or you can help to fill in a blank, please let us know ( Also, there are a few basic assumptions about the 1937 AAR Box Cars that will serve as defaults (and hence, will not be mentioned in the table, but will be assumed unless stated otherwise.)

Cars listed are 10'0" IH
Doors are Youngstown corrugated
Roofs are Murphy Rectangular Panel
Trucks are 50-ton AAR cast sideframe
Underframe is AAR standard

Table of as built 1937 AAR Box Car Prototypes (Letter - 8.5 x 11) (Tabloid - 11 x 17) - Updated 2/20/2017 (Adobe Acrobat PDF file, compiled by Ed Hawkins)

Photos of 1937 AAR Box Cars on the Steam Era Freight Cars Site

Bessemer & Lake Erie 1937 AAR Box car 91367
Chesapeake & Ohio 1937 AAR Box car 5469 (Deco ends)
Detroit & Mackinac 1937 AAR Box car 2913
Florida East Coast 1937 AAR Box car 21009

New Haven 1937 AAR Box car 32077
Northern Pacific 1937 AAR Box car 17497
Southern Pacific B-50-19 1937 AAR Box car 38311