00454962

Component

http://onlinepubs.trb.org...trr/1985/1006/1006-002.pdf

https://scholar.google.co...reif&publication_year=1985

Analytical and experimental study results of high center of gravity freight car response to a range of track cross-level deviations are presented. Based on the criteria of excessive car body roll or excessive wheel lift, boundaries between safe and unsafe track cross-level conditions are established. These studies and industry experience indicate that although isolated low joints producing crosslevel deviations as large as 4 in. can be safely traversed, at the critical harmonic roll speed, a continuous series of 0.75-in. low joints will produce an unacceptable roll response for high center of gravity cars resulting in a potential derailment. The results also indicate that a 400-ft length of track is sufficient for the harmonic roll resonance to build to a critical amplitude. The cross-level variation conditions that form the boundaries between safe and unsafe harmonic roll response are reviewed. The results are then combined in a heuristically developed performance index that is intended to identify potentially unsafe track conditions without rejecting an excessive amount of track that does not have the potential for producing harmonic roll derailment. Analyses have been conducted on track geometry measurements of selected Class 2 and Class 3 track to evaluate the statistics of the proposed cross-level index. The results indicate that the index does successfully identify potential harmonic roll situations while permitting occasional large cross-level deviations that may be undesirable but are not unsafe. Illustrations of the response of the index to selected measured track geometry conditions are included.

Publication of this paper sponsored by Committee on Track Structure System Design. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01419889

pp 9-16

1985

Transportation Research Record

0309038162

Print

Figures (16) ; Photos (2) ; References (9)

Defects; Freight cars; Instrumentation; Rail joints; Railroad tracks; Ratios; Rocking; Rolling; Structural design; Train track dynamics

Lateral stability; Track geometry

Design; Highways; Railroads

TRIS, TRB

Jul 31 1988 12:00AM

• DEMONSTRATION OF THE RAIL ENERGY COST ANALYSIS PACKAGE: THE ROUTE PERSPECTIVE (RECAP II)
• ESTIMATES OF RAIL TRANSIT CONSTRUCTION COSTS
• GRANULAR DEPTH REQUIREMENT FOR RAILROAD TRACK
• RESEARCH ON RAILROAD BALLAST SPECIFICATION AND EVALUATION
• TECHNIQUES FOR CONTROLLING RAIL CORRUGATION
• THE EVOLUTION OF WASHINGTON METRO'S TRACK STANDARDS
• TRACK REHABILITATION AND NEW CONSTRUCTION IN AN OPERATING ENVIRONMENT AT BART