Technical Reports

Selected Topics in Railroad Tank Car Safety Research Volume I: Fatigue Evaluation of Prototype Tank Car Head Shield

  • 01
  • Aug
  • 1978
AUTHOR: Federal Railroad Administration: Milton R. Johnson
SUBJECT: Hazardous Materials, Safety Advisories, Safety Regulatory Analysis, Safety Performance Measures
KEYWORDS: Hazardous Materials, Tank cars, Head Shields, Fatigue Analysis
ABSTRACT: The characteristics of a prototype head shield for hazardous material tank cars were evaluated with respect to the maintenance of its structural integrity under normal service conditions. The primary concern was with the resistance to fatigue damage of head shield connections to the tank car. The evaluation was conducted by performing tests on a tank car equipped with the shield. The shield and its supporting structure were instrumented to determine the principal forces acting within the structure and at points of attachment to the tank car. Both car-coupling impact and over-the-road tests were conducted. The impact tests were conducted at speeds of from 3 to 8 mph. The over-the-road tests included 432 miles of operation at speeds up to 55 mph. Evaluation of the data revealed that the car-coupling impact environment was the most severe. A definite fatigue life was indicated for the most severely stressed region of the supporting structure. The most severe over-the-road environment occurred with the loaded car at speeds above 45 mph when the main suspension bottomed out. The loads associated with this phenomenon were below those of the car-coupling impact environment.