The sideframe of a railway car truck are constructed such that basic overallsideframe appearance is maintained, but the actual construction results in a moreefficient use of the materials as a means of reducing the sideframe weight. This meansthat material is used according to how the stresses are encountered by the sideframe,dictating that the sideframe midsection is structurally heavier than the sideframe ends.Maximization of this construction is provided by shaping the entire sideframe into asolid, unitary cross-sectional ?-beam shape. A solid top flange of the?-beam corresponds to the typical top compression member while the solid bottomflange corresponds to the typical bottom compression member. The solid vertical web,which interconnects the top and bottom flanges is a typical, thereby allowing the web toabsorb forces which would normally have to be absorbed by either top or bottommember. This feature allows the sideframe to be lighter, yet structurally stronger becausethe top and bottom members can now be cast dimensionally smaller. To take advantageof the weight savings even further, the ?-beam shape has a structurally tapering thicknessfrom the midsection to the ends and this corresponds to the loading experienced by thesideframe. The open, ?-beam exterior allows for easier and more reliable inspection, aswell as improved casting quality due to a substantial reduction in casting core usage.
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