Section. A specific type of repair in which replacement material is fitted flush with the
original component and the entire profile of the component's cross section is replaced.
Hole. A circular penetrating puncture through any part of the CROP.
Pinhole. A small hole less than 1/8 in. (3.18 mm) in diameter. A pinhole typically results
from a tiny skip or porosity in a weld and usually is only detected during a light leak test.
Corrosive Failure. Corrosive failure (galvanic or electrolytic) is determined when the cor-
roded metal can be punched by striking the area lightly with a welder's hammer.
(10) Caulking. A sealant compound used to provide water tightness around patches in panels,
around riveted seams, in holes of pop rivets, in joints between dissimilar metals, in gaps
between floor board edges and in gaps where the floor boards adjoin the interior wall.
(11) Undercoating. Bituminous material or other waterproof coating brushed or sprayed on the
entire underside of the container floor to protect all of the metal understructure against cor-
Underneath the CARC paint, the M3A1 CROP is completely galvanized with zinc. Zinc fumes,
released by the burning of the zinc during welding repairs, are extremely toxic. Welding per-
sonnel must exercise extreme caution or wear respirators, when performing welding repairs.
When weldment cracks are discovered, it is recommended that they be repaired at the next ser-
vice interval to prevent the length of the crack from increasing and to minimize repair. The fol-
lowing inspection procedures are to be considered as guidelines only. Any cracks discovered
during the inspections considered more significant, especially from a safety stand point should
be referred to the supervisor for weld repair decisions. This would include cracks identified in
any main structural areas (main frame and main rail flanges) and cracks that have opened and
could lengthen rapidly during loading/unloading operations.
Weldment Points. Thoroughly inspect all weldments for cracks, chips or other damage.
Areas include the end structure assembly, pin blocks, main beams, center tubes, cross beams, front and end beams,
ISO twistlock housings, multipurpose provision rings and mounting brackets and D-ring mounting bars. Particular
attention should be paid to the difference between a crack in the coatings and a crack in a weld or parent material.
Suspected cracks in welds or parent material should be confirmed by using non-destructive examination techniques
(e.g. ultra sound test or Zyglow inspection). Inspect welds for acceptable crack length limits using the following