The rocking response of railroad freight cars to track cross-level variations is studied using: (1) a reduced complexity digital simulation model, and (2) a quasi-linear describing function analysis. The reduced complexity digital simulation model employs a rail truck model that neglects the high-frequency dynamics of the bolster and wheelset masses, yet includes kinematic center plate, side bearings, and wheelset nonlinear effects. This model has computation-time requirements that are less than one eighth those of more detailed computer simulation models and agrees within 15% percent for the prediction of roll angle, side bearing force, center plate force and wheel force at maximum roll angle response with the more detailed models. A study of quasi-linear describing function techniques to compute the steady-state response of freight cars to equivalent sinusoidal cross-level track variations has demonstrated the feasibility of the technique for the types of nonlinearities important in car response. This technique, which computes steady-state response from a set of nonlinear algebraic equations rather than by numerical integration, is effective for parametric studies in which a series of the responses is required as a parameter is varied incrementally since once the solution is obtained for one set of parameter values, additional responses for an incremental change in the parameter are obtained efficiently.

  • Record URL:
  • Supplemental Notes:
    • MIT is under contract to Transportation Systems Center, DOT.
  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Mechanical Engineering
    Cambridge, MA  United States  02139

    Transportation Systems Center

    55 Broadway, Kendall Square
    Cambridge, MA  United States  02142

    Federal Railroad Administration

    Office of Rail Safety Research, 1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Platin, B E
    • Beaman, J J
    • Hedrick, J Karl
    • Wormley, D N
  • Publication Date: 1976-9

Media Info

  • Features: Appendices; Figures; Photos; Tables;
  • Pagination: 86 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00144091
  • Record Type: Publication
  • Source Agency: Federal Railroad Administration
  • Report/Paper Numbers: FRA-OR&D-76-293 Final Rpt.
  • Contract Numbers: DOT-TS-11201
  • Files: NTIS, TRIS, USDOT
  • Created Date: Jan 16 1977 12:00AM