Effect of Track Twist on Vehicle Dynamic Performance

Results of tests conducted at the Transportation Technology Center (ITC), Pueblo, Colorado, indicate that vehicle response to track twist varies significantly with car type. Critical response variables include car body torsional stiffness, truck spacing, track alignment (tangent or curve), track geometry and wheel/rail friction coefficient. Test data collected during this project provide an experimental basis for investigation of performance-based track safety limits. Track twist is defined as a variation in cross level between two points along the track. Excessive twist can cause truck center plate unloading on tangent track as indicated by wheel unloading, or wheel climb on curved-track as indicated by high wheel or axle L/V ratios. The limiting wheel unloading and L/V ratio criteria specified by the industry for new car acceptance (90 percent reduction of static vertical wheel force, 1.0 single wheel L/V ratio and 1.5 axle sum L/V ratio) were used as the guideline limits for this test. Three vehicles were tested in an empty load condition - a 100-ton, 89-foot center beam flatcar, a 100-ton covered hopper car and a 70-ton tank car - over cross level and combined cross level/alignment perturbations on tangent, 7.5-degree curve, and 12-degree curve test zones.

• Record URL:
  • https://www.fra.dot.gov/eLib/details/L16558#p1_z25_gD_lRT_y1997
• Supplemental Notes:
  • Date on cover: June 5, 1997.
• Corporate Authors:

  Association of American Railroads

  Transportation Technology Center, P. O. Box 11130
  Pueblo, CO  United States  81001

  Federal Railroad Administration

  Office of Research and Development, 1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Publication Date: 1997-3-13

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Draft Report
• Features: Figures; Photos; References; Tables;
• Pagination: 78p

Subject/Index Terms

• TRT Terms: Flat cars; Hopper cars; L/V ratio; Railroad safety; Railroad tracks; Tank cars; Train track dynamics
• Uncontrolled Terms: Test data; Track twist
• Subject Areas: Design; Railroads; Vehicles and Equipment;

Filing Info

• Accession Number: 01679501
• Record Type: Publication
• Files: TRIS, ATRI, USDOT
• Created Date: Aug 27 2018 5:23PM