Technical Reports

Peacekeeper Rail Garrison Vehicle Characterization Test of Triplet Cars, ATSF 90004 and 90006

  • 01
  • Oct
  • 1991
AUTHOR: Eric Bier
OFFICE: RPD
REPORT NUMBER: DOT/FRA/ORD- 92/24
SUBJECT: Facilities & Test Equipment
KEYWORDS: Depressed Center Flat Cars, Span Bolster, Suspension Characterization
ABSTRACT: Vehicle Characterization tests were performed on two of three commercial span bolsters cars (Triplet Cars) to gather data in support of the Train Dynamics Model (TDM) prediction of coupled span bolster car performance. The three vehicle characterization tests were: (1) static suspension characterization, (2) quasi-static suspension characterization, and (3) modal response testing. Modal testing was performed to assess any resonant rigid or flexible body modes that may be encountered during track testing. Lower center roll at 0.9 Hz., Sway at 1.1 Hz., and bounce at 2.3 Hz were the only natural frequencies that would be expected to be encountered during operational test speeds over 39-foot wavelength perturbations for the ATSF 90006 car. These frequencies equate to 23, 29, and 61 mph, respectively. Lower center roll at 0.8 Hz. and bounce at 2.4 Hz were the only natural frequencies that would be encountered during operational test speeds for the ATSF 90004 car. These frequencies equate to 20 mph and 64 mph, respectively. Quasi-static truck characterization tests were performed to characterize the vehicle suspension for input to the TDM. The ATSF 90006 car was equipped with 100-ton design ride control trucks. The average vertical stiffness and damping were 44.8 kips/inch and 10.7 kips for one spring nest. Lateral stiffness and damping were 40.6 kips/inch and 26.5 kips per spring nest. Truck roll rate was 75,386 kip-inches/radian. The ATSF 90004 car was equipped with 125-ton design ride control trucks. The average vertical stiffness and damping were 50.1 kips/inch and 10.7 kips per spring nest. Average lateral stiffness and damping were 42 kips/inch and 22.8 kips, per spring nest. Truck roll rate was 67,775 kip-inches/radian. Static suspension characterization tests consisted of four subsets of air bearing table tests. They were: span bolster yaw moment, truck yaw moment, longitudinal stiffness, and axle yaw stiffness. Air bearing table test data appeared to be usable for TDM development.
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