TM 5-628/AFR 91-44
APPENDIX B
FIELD IDENTIFICATION OF RAIL DEFECTS
fects are identified in the defect descriptions pre-
B-1. Rail defects may be observed in track.
sented in this appendix. Table 7-1 of these stand-
This appendix presents definitions relating to rail
ards presents a listing of rail defects, operating re-
and brief descriptions of the common rail defects
strictions, and remedial actions.
observed in track. Figure B-l presents common rail
nomenclature, and figure B-2 shows the relative
positions of planes through the rail.
B-3. Field identification of rail defects.
These descriptions are presented in alphabetical
order to assist in identifying defective rails in track.
Refer to TM 5-627/AFM 91-33 for additional
information.
a. Bolt hole crack.
(1) Description. A progressive fracture
originating at a bolt hole.
B-2. Not all rail defects are critical.
(2) Appearance in track. Bolt hole cracks
A critical defect is a rail defect that will effect the
are not visible until a bolt or a joint bar has been re-
safety of train operations. Noncritical defects are
moved unless the defect has progressed beyond the
defects that occur in the rail but do not effect the
bar. They may be recognized by a hairline crack
structural integrity of the rail or the safety of the
extending from the bolt hole (fig B-3).
trains operating over the defect. Noncritical de-
B-1
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