On Sep 8, 2010, at 8:08 PM, Mark M wrote:

I mentioned in an earlier post about these cars. Have two photos and
searched the messages and found post of USN fifty foot boxcars with
similar ends and roof.
Stan Rydarowicz has Carbuilders Flat 12 panel riveted roof for 1937
AAR boxcar.
Does anyone know if these might be the right roof?

Mark,
Stan's flat-panel riveted roof was similar to but unlike the B&O
M-55/A/B box cars, which had a rather unusual roof comprised of flat
riveted sheets with depressed roof sheets adjacent to the ends. The
purpose of the depression was to reduce the car's height near the edge
of the latitudinal running board (i.e., the roof grab iron) to stay
within clearance restrictions. An order of WLE box cars built in 1948
had the same type of roof. The depression in the roof sheet closest to
each end was slightly wider than the latitudinal running board and
1-7/16" lower than if the roof extended straight to the ends without
the depression.
Regards,
Ed Hawkins