Wheel Unloading of Rail Vehicles Due to Track Twist

Details

• Creators:
  Tyrell, David ; Weinstock, H. ; Greif, R.
• Corporate Creators:
  John A. Volpe National Transportation Systems Center, (U.S.)
• Corporate Contributors:
  United States. Federal Railroad Administration
• Subject/TRT Terms:
  Cross Leveling Curvature Curved Track Deformation Derailments Railroad Cars Railroad Tracks
• Publication/ Report Number:
  DOT/FRA/ORD-85/14, DOT-TSC-FRA-84-7,
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Technical report; May 1983-Sep 1985
• Corporate Publisher:
  United States. Federal Railroad Administration
• NTL Classification:
  AGR-INFRASTRUCTURE-INFRASTRUCTURE ; AGR-INFRASTRUCTURE-Railroads ; NTL-RAIL TRANSPORTATION-RAIL TRANSPORTATION ; NTL-RAIL TRANSPORTATION-Rail Safety ; NTL-SAFETY AND SECURITY-Vehicle Design ; NTL-SAFETY AND SECURITY-SAFETY AND SECURITY ; NTL-SAFETY AND SECURITY-Rail Safety
• Abstract:
  An analysis is presented describing the effect that track twist has on the loads carried by the wheels of a rail car. Wheel unloading is determined as a function of the difference in crosslevel between the truck centers of the car. The different vehicle characteristics that affect a car's reaction to track twist are determined. It is found that light, torsionally stiff cars are the most susceptible to wheel unloading due to track twist. Using the results of a previous study where lateral wheel/rail force was determined as a function of curvature, the difference in crosslevel between truck centers that will cause Nadal's Limit for wheel climb to be exceeded is determined as a function of curvature. This difference in crosslevel between truck centers is normalized to 31 ft so that maximum track twist, as it is commonly defined, is determined as a function of curvature. It has been found that for less that 6 deg of curvature and at low speeds, most rail cars can withstand up to 1.5 in. of track twist in 31 ft. The amount of track twist that a car can withstand decreases with increasing curvature, and at 15 deg of curvature the amount of track twist that most railcars can withstand has dropped to 1.0 in.
• Format:
  PDF
• Funding:
  RR519/R5305
• Collection(s):
  Volpe Center
• Main Document Checksum:
  urn:sha256:b8f0d48d8ebd046701dd6a96328016c117ffdfe824eb141e9af52f991fe3c66f
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/11952/dot_11952_DS1.pdf
• File Type:
  [PDF - 1.78 MB ]