(3) Truck equipped with a snubbing device that is ineffective, as evidenced by a
snubbing friction element that is worn beyond a wear indicator; a snubber wear plate that is loose,
missing (except by design), or worn through; a broken or missing snubber activating spring; or a
snubber unit that is broken. See Figures A-19 and A-20 for examples of typical snubbing devices.
See Figure A-21 for an illustration of wear limit indicators of friction castings or elements.
(4) A truck with a broken or leaking snubbing units in the case of hydraulic snubbing
units as evidenced by clearly formed droplets of oil or other fluid.
(5) The truck springs do not maintain travel or load.
(6) The truck springs are compressed solid or the wrong type.
(7) More than one outer truck spring which is broken or missing in any spring cluster.
(8) The truck spring dimensions are out of limits. (See Table A-5).
(9) Badly worn brake beam shelf support that it does not support the brake beam.
(10) The brake hanger bracket bent or worn oblong to a depth of 1/2 of its original
diameter or worn oblong so that remaining material is not less than 60% of the original section.
(11) The vertical wear liner has a piece loose or missing.
Figure A-22 shows an example of a bolster gib and side frame wear plate.
When side frames are replaced, they should be matched for wheelbase (distance between pedestal
center lines). See Figure A-23, method of marking and mating cast steel track side frames. A uniform
practice for marking truck side frames to permit pairing of frames on same truck, with respect to
dimensions between centers of journal boxes (wheelbase), has been adopted. Present standards
permit a tolerance of plus or minus 3/16 inch in this dimension which, unless controlled, results in a
possible total variation of 3/8 inch in the wheelbase dimension on opposite sides of the same truck.
Under the adopted system, the number of buttons remaining on the side frame indicates the variation
over the nominal dimension, as shown by tabulation, and frames having the same number of buttons
or when one of the same number is selected for use on the same truck. By following this method, the
variation in wheelbase dimension would not exceed .150 inch. Similar procedure may be followed in
the case of reclaimed side frames not provided with buttons by gauging the dimension between center
of journal boxes and stenciling the proper designation number on outside wall of left hand journal
box, in same location as prescribed for the mating buttons.
Friction elements should be replaced when friction face is worn to the extent that limit of wear
indicator is obliterated.
Building up of worn surfaces or welding of cracks on side frames permitted only in cross-hatched
area of diagram and provided the material remaining in the part to be built up is equal to 60% of the
original section or the crack does not extend more than 40% through the cross-sectional area of the
casting. See Figure A-24, illustration of repair welding of truck side frames.
A - 20