Technical Reports

Impact Performance of Draft Gears in 263,000 Pound Gross Rail Load and 286,000 Pound Gross Rail Load Tank Car Service

  • 01
  • Jun
  • 2006
AUTHOR: Anand Prabhakaran, Robert Trent, Vinaya Sharma
OFFICE: RPD
REPORT NUMBER: DOT/FRA/ORD-06/16
SUBJECT: Hazardous Materials
KEYWORDS: Draft gear, tank car safety, tank car impacts, stub sill stresses
ABSTRACT: This project quantified the impact performance of draft gears on tank cars for both the 263,000 and 286,000 gross rail load (GRL) conditions and the corresponding effect on the structural integrity of stub sills. Full-scale physical impact testing with an instrumented tank car for the 263,000 GRL case using 6 different draft gear combinations of prime, average, and soft draft gear conditions were performed. Impact speeds of 2 to 9 mph were tested. Loss in draft gear performance with age/use along with performance comparisons of draft gears qualified under M-901G versus M-901E were obtained. Test results from the 263,000 GRL cars are presented and used to validate an finite element analysis model with scaled up car mass to predict draft gear performance for the 286,000 GRL case. This study showed that draft gears in prime condition are the most effective at reducing car impact forces, especially at higher speeds where the most damage occurs. Draft gears in the soft condition provided the least protection. M-901G gears offered better performance at the higher speeds of interest than the M-901E gears. The average setup, a combination of soft and prime gears, performed better than soft gear setup.

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