Roller bearings with no grease fittings shall not be lubricated. Plastic or metal plugs
on the end cap should not be removed.
Any roller bearings involved in a derailment shall be replaced if an inspection finds
defects. This inspection shall include checking the following: the outer cup and end
caps for cracks or breaks, seals, end cap screws or back rings that are loose, damaged,
or missing and for internal roughness or catches in the rotation of the bearing. Lateral
movement of the bearing shall be limited to 1/8 inch for cylindrical bearings and 1/16
inch for tapered bearings. Any visible movement vertically shall be considered a
Cars utilized for the movement of Class 1 explosives should be equipped with roller
Any roller bearings that have been submerged in any fluid or powdery substance shall
Any roller bearing found with any external parts visibly cracked broken or bent or any
of the defects noted in derailment inspection replacement criteria shall be replaced.
Bearings shall be replaced in pairs.
Cracked, broken, or missing roller bearing adapters shall be replaced. Roller bearing
adapters shall be replaced if roller bearings have wear on either end of the bearing
When wheel sets are removed, the adaptor shall be checked with an adapter wear
gauge. See Figure A-4 for an illustration and cross section of a bearing adapter.
If the crown on top of the adapter has worn to such a condition that frames would
bear on relief portions, adapters should be renewed.
See Figures 3-6 through 3-7 and Figure A-5 for illustrations of some defects discussed below.
See Figures A-6 through A-15 for methods of utilizing AAR wheel gauges. Wheel sets shall be
checked for equal back-to-back measurements at three locations approximately 120 degrees apart.
Wheel sets shall be replaced if the distance between the inside gauge of the flanges on narrow
flange wheels is less than 53 inches or more than 53 1/2 inches. The distance between the inside
gauge of the flanges on wide flange wheels shall not be less than 53 inches or more than 53 1/4
inches. Wheels shall be replaced if any of the following situations exist:
Thin flange, 15/16 inch thick or less, at a point 3/8 inch above the tread of the wheel.
Flange height extending 1 1/2 inches or more above the approximate centerline of,
tread or vertical flange surface extending 1 inch or more from the tread.