Technical Reports

Analytic Studies of the Relationship Between Track Geometry Variations and Derailment Potential at Low Speeds

  • 01
  • Sep
  • 1983
AUTHOR: Fred B. Blader
OFFICE: RPD
REPORT NUMBER: FRA/ORD-83/16
SUBJECT: Track/Train Interactions
KEYWORDS: Computer Simulation, Mathematical Dynamic Curving, Hunting, Wheel Rail Forces, Profiles, Track Safety Standards
ABSTRACT: This report describes analytical studies carried out to define the relationship between track parameters and safety from derailment. Problematic track scenarios are identified reflecting known accident data. Vehicle response is investigated in the 10-25 mph speed range, using an analytic model of a freight vehicle to identify critical values of body roll, and incipient wheel drop and rail climb, on track with weak lateral restraint. The track model includes gauge variation as well as alignment and cross-level in curves and the vehicle represents a 100-ton hopper car. Model results compare well with experimental results. Safe values for gauge and crosslevel are identified for curved track containing lateral cusps at outer rail joints with and without crosslevel cusps at staggered joints. Safe values of alignment are identified for sinusoidal alignment variation with constant gauge on tangent track and in curves up to 10 degrees. Recommendations are made on improvements to the computational efficiency and accuracy of the simulation and on further efforts required to identify completely safe values for track over the range of speeds, vehicle types and track conditions encountered in service.
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