MATHEMATICAL MODELING OF DODX RAILCARS

This report presents the results of a project conducted to determine the roll stability characteristics of large capacity freight cars, 100 to 200 ton, loaded with high center of gravity containers. The model, obtained from AAR, is a 22 degree-of-freedom, non-linear, time domain model of railcars equipped with two axle trucks. The model was modified to include hydraulic dampers, an improved Coulomb friction damping model, and a track input to simulate perturbed track specified in AAR specification D-65. Also a lower order integration technique and a larger integration technique and a larger integration stepsize were employed to reduce computer run time. The model was validated against each of four vehicles on which full scale field tests had been conducted. In three of the four cases sufficient agreement was found between the results of the model and those of the field test to proceed with further simulations of other load/suspension configurations. Results of these simulations suggest that improvement in roll stability can be achieved by reducing the vehicle suspension spring rate or similarly increasing the load. It was also found that one of the vehicles studied possessed a dead band in the stroke of the hydraulic stabilizer. By modifying this stabilizer to operate over the full stroke, vehicle dynamic performance should show improvement.

• Record URL:
  https://railroads.dot.gov/elibrary/mathematical-modeling-dodx-railcars
• 
• Corporate Authors:

  ENSCO, Incorporated

  Engineering Test and Analysis Division
  Alexandria, VA  United States  22303

  Federal Railroad Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Jones, C T
• Publication Date: 1980-2

Media Info

• Media Type: Digital/other
• Features: Appendices; Figures; References;
• Pagination: 168 p.

Subject/Index Terms

• TRT Terms: Center of gravity; Container on flat car; Damping (Physics); Derailments; Flat cars; Freight cars; Heavy duty trucks; High capacity cars; Mathematical models; Prevention; Rocking; Rolling; Snubbers; Three axle trucks; Train track dynamics; Trucks by number of axles; Two axle trucks; Vehicle dynamics
• Old TRIS Terms: Four axle trucks; Freight car dynamics; Rock and roll
• Subject Areas: Motor Carriers; Railroads; Security and Emergencies;

Filing Info

• Accession Number: 00319060
• Record Type: Publication
• Report/Paper Numbers: FRA/ORD-78/47 Final Rpt., DOT-FR-77-20
• Contract Numbers: DOT-FR-64113
• Files: TRIS, USDOT
• Created Date: Sep 16 1980 12:00AM