Technical Reports

Tank Car Operating Environment Study: Phase I

  • 01
  • Oct
  • 2007
AUTHOR: Kevin Koch
OFFICE: RPD
REPORT NUMBER: DOT/FRA/ORD-07/22
SUBJECT: Hazardous Materials
KEYWORDS: Tank car coupler forces, railcar impact test, correlation of accelerometer data with coupler forces
ABSTRACT: This report documents the results of controlled testing conducted during the first phase of a tank car operating environment program involving the Association of American Railroads, the Railway Supply Institute (formerly the Railway Progress Institute), the Federal Railroad Administration, and Transport Canada. Strain gages, accelerometers, and an instrumented coupler were installed on a stub sill tank car during this phase of testing. This car was then subjected to a series of tests applying a range of forces to the coupler. These included the application of controlled vertical forces, car-to-car impact tests, and a short duration over-the-road test. Results showed that significant correlation could be established between strain gage output and output from the instrumented coupler. This indicates the strong possibility that longitudinal and vertical coupler forces can be inferred only from the output from four strain gages installed on the stub sill. Results also showed a correlation between accelerometer output (in the form of a shock response spectrum (SRS)) and peak longitudinal coupler forces, especially for impact forces above 400,000 pounds. This indicates a possibility that SRS values from only two accelerometers can be used to infer the magnitude of peak coupler forces that occur during yard impacts. During Phase II of this investigation, this transducer system will be tested under standard in-service conditions to further prove the concept and usefulness towards establishing tank car coupler force operating environment profiles.

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