Wednesday, January 9, 2019

Wordy Wednesday - Baltimore & Ohio 1937 AAR Box Car M-55A B&O 465885

San Diego, California, December 26, 1954, Col. Chet McCoid photo, Bob's Photo
In 1942, the Baltimore & Ohio added 900 class M-55A box cars that hewed to the 1937 AAR design, but liberally took advantage of the ability to choose specialties including ends, roof, and underframe. The sides were the typical riveted ten-panel sides of the 1937 AAR design. The B&O opted for Carbuilder's (the generic term for a builder's proprietary-design doors, ends, roofs, etc.) ends and roofs. These specialties were Pullman-inspired as the cars were constructed by Pullman-Standard. As was a de facto standard for the B&O in that era, the cars were equipped with the Duryea Cushion underframe.

Chattanooga, Tennessee, 1943, FSA-OWI Collection, Library of Congress
The flat, riveted roof possessed a distinguishing "step" between the last roof end panels and the adjacent panels, as can be seen here. The end ribs were roughly triangular in cross-section, with a taper near the end corners, with the last bits of the ribs following the radius of the corner.

The top photo is another of my favorites from Col. Chet McCoid. It was recorded either very early or late in the day when the low light angle provided excellent and even coverage of the surface details. This car had not been repainted since it was built, so it has a dozen years of service reflected on its surface. Of note are the rather low crossbearers of the Duryea Cushion underframe and the XLT (or Tatum) slack adjuster, the rectangular appendage to the right of the AB brake reservoirs. John Tatum was a B&O employee and prolific inventor with many patents for railroad-related appliances, including this slack adjusting device. There is an article about the adjusters in Volume 44 of The B&O Modeler, including how to model these devices that were common to many B&O freight cars.


  1. Ted, As a B&O modeler I am going to need several of this class. The best thing that I have come up with is to use the intermountain 1937 AAR boxcar as a starting point. I know that I would have to modify the area around the door and the lower side sill. I figured out how to do the ends, but the roof has always stumped me. Any suggestions? Was also wondering if the Duryea underframe that you sell for the M-26 boxcar might be able to be modified for this boxcar.
    Dan Sobieck

  2. This seems like a good candidate for a parts set ...


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