The purpose of this report is to present data that may be used for comparing rubber type draft gears versus friction type draft gears under identical conditions of impact speed, car structure, and lading. These data also may be used for establishing minimum requirements for affording adequate protection against end shock to freight cars of all types and their lading. Another purpose of this report is to call attention to the fact that the cushioning capacity of any of the A.A.R. certified draft gears, regardless of type, is not sufficient to afford adequate shock protection to freight cars and their lading under the severe conditions of hump yard service. In view of the fact that a limited survey of impact conditions in local hump and flat switching yards showed that 50% of the observed impacts occurred at 6 mph and above, and 28% at 8 mph and above, it can be concluded that neither the friction type draft gear nor the rubber draft gear investigated in this report has adequate cushioning capacity to properly protect freight car and their lading under the severe conditions that are encountered in switching service. The rubber draft gear has considerably more cushioning capacity than the friction gear. Top and bottom bolster cover plates are stressed excessively by impacts above 6 mph. The improvement in cushioning capacity and smoothness of action of the rubber draft gear is due to the elimination of metal-to-metal over-solid limiting stops.

  • Corporate Authors:


    Research and Development Department
    Hammond, Indiana,   United States 
  • Publication Date: 1950-11-15

Media Info

  • Features: Appendices; Figures; Photos;
  • Pagination: 83 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00039919
  • Record Type: Publication
  • Report/Paper Numbers: Tech Rpt
  • Files: TRIS
  • Created Date: Jul 8 1994 12:00AM