published by the AAR. The rule numbers and AAR
symbols are given with the defects in the following
a. Burnt rim or flange (Rule 71--AAR symbol
71-A). If a portion of the flange or rim breaks off
with a coarse fracture and a rough granular surface
shows, the wheel should be removed from service.
The cause of the burnt-rim or -flange defect is
overheating during the manufacturing process. The
wheel shown in figure 2.13 has a burnt-flange
Figure 2.12. Gaging Broken Rims.
b. Shattered rim or flange (Rule 71--AAR symbol
71-B). When a portion of the rim or flange parts from
the remainder of the wheel so that a smooth surface is
exposed for any considerable distance, the defect is
known as a shattered rim or flange. The wheel should
be removed from service, and a heavy coating of grease
should be applied to the exposed area to preserve the
defect, as originally detected, for investigation. Look at
figure 2.14 and notice the difference in this defect as
compared to the burnt flange shown in figure 2.13.
c. Spread rim (Rule 71--AAR symbol 71-C).
Figure 2.13. Burnt-Flange Defect.
When the front or the back face of the rim spreads
outward from the tread, the wheel has a spread-rim defect as shown in figure 2.15. This condition usually
indicates an interior defect,