Side frame and bolster for a railway truck and method for manufacturing same

Abstract

A method of manufacturing a bolster of a rail car that includes a pair of shoe pockets at respective ends configured to be inserted into bolster openings of respective side frames includes providing a bolster pattern for forming a drag portion and cope portion of a mold. Cores that define an interior region of a cast bolster are also provided. The bolster pattern and the cores are configured to constrain shoe pocket angles within about ±0.5°.

1 . A method of manufacturing a bolster of a rail car that includes a pair of shoe pockets at respective ends configured to be inserted into bolster openings of respective side frames, the method comprising:
 providing a flask;   inserting a bolster pattern into the flask;   filling the flask a molding material around the bolster pattern;   removing the bolster pattern from the molding material to thereby form for a drag portion and cope portion of a mold;   curing the mold;   removing the cured mold from the flask;   inserting one or more cores that define an interior region of a cast bolster into the drag portion of the mold; closing the mold;   pouring a molten material into the mold to form a bolster casting;   removing the bolster casting from the mold, wherein a margin of error in shoe pocket angles is within about ±0.5°   removing rigging from the side frame casting; and   finishing the side frame casting.   
     
     
         2 . The method according to  claim 1 , wherein a surface finish of the cast bolster is less than 750 micro-inches RMS. 
     
     
         3 . The method according to  claim 2 , wherein a surface finish of the pair of shoe pockets is less than 500 micro-inches RMS. 
     
     
         4 . The method according to  claim 1 , wherein a shoe pocket side wall draft angle of the cast bolster is no more than about ¾ degree. 
     
     
         5 . The method according to  claim 1 , wherein the bolster pattern and one or more cores are configured so that a margin of error in a spacing between respective inner and outer gibs of the cast bolster is within about ±0.063 inches. 
     
     
         6 . The method according to  claim 1 , wherein respective inner and outer gib draft angles are no more than about ¾ degree. 
     
     
         7 . A method of manufacturing a bolster of a rail car that includes a pair of shoe pockets at respective ends configured to be inserted into bolster openings of side frames, the method comprising:
 providing a flask;   inserting a bolster pattern into the flask;   filling the flask with a molding material around the bolster pattern;   removing the bolster pattern from the molding material to thereby form a drag portion and cope portion of a mold;   curing the mold;   removing the cured mold from the flask;   inserting one or more cores that define an interior region of a cast bolster,   closing the mold;   pouring a molten material into the mold to form a bolster casting;   removing the bolster casting from the mold, wherein a margin of error in a width between the pair of shoe pockets is within about ±0.063 inches:   removing rigging from the side frame casting; and   finishing the side frame casting.   
     
     
         8 . A method of manufacturing a bolster of a rail car, the method comprising:
 providing a flask;   inserting a bolster pattern into the flask;   filling the flask with a molding material around the bolster pattern;   removing the bolster pattern from the molding material to thereby form for a drag portion and cope portion of a mold;   curing the mold;   removing the cured mold from the flask;   inserting one or more cores that define an interior region of a cast bolster, wherein at least some of the one or more cores define one or more core prints for positioning the one or more cores within the drag portion of the mold, and wherein a distance between an outside surface of the one or more core prints that faces a sidewall of the drag portion and the cope portion of the mold and a surface of the drag portion of the mold that is closest to and generally parallel with the outside surface of the one or more core prints is less than or equal to about 0.030 inches;   closing the mold;   pouring a molten material into the mold to form a bolster casting;   removing the bolster casting from the mold   removing rigging from the side frame casting; and   finishing the side frame casting.   
     
     
         9 . The method according to  claim 8 , wherein the bolster pattern and one or more cores are configured so that a margin of error in a wall thickness of a cast bolster is within ±0.02 inches.