Technical Reports

Structural Adequacy of Freight Car Truck Castings and Wheels

  • 07
  • Oct
  • 1977
AUTHOR: Johnson, M. R.
KEYWORDS: Railroad cars, Freight cars, Fatigue(Materials), Castings, Wheels, Loads(Forces), Fatigue life, Cracking(Fracturing), Failure, Safety, Reliability, Standards, Fatigue strength at N cycles, Railroad trucks, Fatigue standards, Safety standards
ABSTRACT: The structural adequacy of freight car truck castings and wheels to resist fatigue damage is reviewed. The environmental load data described in an earlier report under this program and additional load data which have only recently become available are used to calculate the expected fatigue life under various assumptions of the stresses present in the components. It is found that under most conditions the components should not develop fatigue cracks. This confirms the observation that there are a relatively small number of fatigue failures of these components in service. Since failures of these components can lead to serious derailments, it is important that the circumstances leading to a higher risk of fatigue failure be identified so that under these circumstances truck components can be subjected to more frequent and stringent inspections under the railroad freight car safety standards of the FRA. The results of tests to determine the fatigue strength of wheel plates are also described. The tests showed that there is a substantial safety margin with respect to fatigue when one considers the effects of lateral loads acting on the wheel.