Technical Reports

Field Testing of High Degree Revenue Service Track for Buckling Safety Assessment

  • 01
  • Jan
  • 1995
AUTHOR: D. Thomson, G. Samavedam, W. Mui, A. Kish
SUBJECT: Rail and Infrastructure Integrity
KEYWORDS: Continuously Welded Rail, Buckling, Thermal Effects
ABSTRACT: This report presents the results of a field study of high degree curves in continuous welded rail (CWR) territory. This program was conducted at two test sites: a 10 degree curve on the Atchison, Topeka, and Santa Fe (ATSF) Railroad near Sante Fe, NM, and a 12 degree curve on the Norfolk Southern (NS) Railroad near Bluefield, UV. The work presented here is part of a major investigation carried out by the Volpe National Transportation Systems Center, for the Federal Railroad Administration (FRA), on thermal buckling of CUR track, with the objective of developing guidelines and recommendations for buckling prevention. The field data collected included rail strain and temperature, rail radial movement, and tie lateral resistance in winter, spring, and summer conditions. Based on strain and temperature data, variations in rail neutral (zero force) temperatures are calculated. Seasonal neutral temperature shifts on the order of 20°F and diurnal shifts on the order of 5°F were typically recorded. The neutral temperature variations due to the rail radial movement (radial breathing) are evaluated. The lateral resistance test results indicated an increase in resistance as a function of traffic volume. Using the neutral temperature data and the track lateral resistance measured in the field tests as inputs, the track buckling potential has been evaluated using the Volpe Center's computer model. The predicted buckling response has been correlated with the observed buckling incidents on some of the track sections.
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