Technical Reports

Controlled Tank Car Impact Tests

  • 01
  • Aug
  • 1992
AUTHOR: R.K. Larson, Jr., B.R. Rajkumar
SUBJECT: Railroad Safety Information Management
KEYWORDS: Tank Car Impact, Safety Vent Nozzle, Surge Pressures during Impact, Impact Conditions
ABSTRACT: A series of controlled tank car impact tests were performed by the Association of American Railroads as part of a Federal Railroad Administration Task Order entitled "Hazardous Materials Transportation Safety Research Test Program." The objective of these tests, in which a weighted locomotive was coupled to a stationary DOT 111A100W2 tank car at different speeds, was to determine the magnitude of surge pressures that the safety vent is exposed to and to test devices that are designed to reduce these surge pressures and prevent the premature rupture of frangible discs. Test results support the following conclusions: when loaded to a shell full condition, a tank car of the design tested will develop safety vent nozzle surge pressures sufficient to rupture 60 and 100 psi frangible discs during impacts that produce coupler forces of 800 kips and 1100 kips, respectively. A large decrease in safety vent nozzle surge pressures results when lading outage is changed from 0 percent to 1 percent. For impact speeds between 5 and 7 mph, substantially higher coupler forces were developed for a test car which was loaded to a shell full condition as compared to a 1 percent outage condition. When installed, two baffle-type safety vent nozzle surge pressure reduces (SPR's) effectively reduced surge pressures acting on frangible discs installed in 2 1/2 inch and 6 1/2 inch diameter nozzle safety vents. The SPR' s prevented the discs from rupturing during coupling impacts involving forces up to 1200 kips.