Technical Reports

Preliminary Evaluation of Rail Vibration Techniques for Rail Force Measurements

  • 01
  • Dec
  • 1980
AUTHOR: W. S. McEwan, G. Born
OFFICE: RPD
REPORT NUMBER: R-437
SUBJECT: Track/Train Interactions
KEYWORDS: Longitudinal Rail Forces, Rail Stresses, Train/Track Dynamics
ABSTRACT: It has been postulated that the vibrational response of a railroad rail, subjected to a sharp mechanical impact, should vary according to the magnitude of the internal longitudinal force. In order to test this hypothesis, a series of tests were conducted at the A.A.R.'s Track Research Laboratory in Chicago, Illinois. These tests involved measurements of the complex acoustic spectra generated in a test rail section by sharp mechanical impacts to the head, as the longitudinal force levels were varied, in increments of about 12,500 pounds, from zero to approximately 200,000 pounds. Also studied were the feasibility of a rail-mounted accelerometer and microphone, located near but not in contact with the rail head, as response transducers, and the effects of changes in geometry between the points of impact (excitation) and response measurement. The results indicated that there were shifts in the relative magnitudes of specific frequency components, as the longitudinal force levels varied, but due the complex nature of the vibrational responses, additional measurements and analyses are needed.

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