00300676

Component

http://onlinepubs.trb.org...s/trr/1978/694/694-009.pdf

https://scholar.google.co...Gray&publication_year=1978

Track and vehicle wear affect the dynamic performance and therefore the economic performance of the railcar-track system. A multiphase test program has been designed to determine the relationship between the dynamic performance of freight vehicles and track condition, vehicle-component wear, and variations in track structure. The first part of this program has been completed, i.e., the development of test, instrumentation, and analysis techniques and the determination of their applications to a baseline dynamic-performance test. The test methodology involves dynamic testing of a high-travel car and a reference or low-travel car. Two test tracks at the Transportation Test Center were used, the facility for accelerated services testing track and sections of the railroad test track. The instrumentation for each test vehicle included precision accelerometers to measure accelerations on the car body, bolsters, and trucks and instrumented wheel sets to measure lateral and vertical forces on the wheels. The analysis of the acceleration data is based on the use of six degrees of freedom, or rigid-body modes, for each primary mass (car body and truck). Statistical processing of the computed modal data is used to determine the effects of track structure and condition on vehicle performance. Transmissibility between truck and car body is calculated to determine the effect of component wear on vehicle performance. Finally, statistical processing of wheel-rail forces is used to obtain lateral-to-vertical force ratios and lateral wheel forces as functions of the track section. The instrumentation and data-processing techniques designed for this program proved effective in evaluating freight-car dynamics. Evaluation of the effects of variations in track structure on vehicle dynamics led to the following conclusions: (a) track containing unsupported bonded joints produced the highest car-body accelerations; (b) curves greater than 4 degrees and discrete events such as turnouts produced high accelerations and wheel forces; and (c) variations in track and roadbed such as ballast-shoulder width and depth, spiking patterns, tie material, and rail anchor type had little if any effect on the dynamic response of the vehicle.

This paper appeared in Transportation Research Record No. 694, Railroad Track and Electrification Studies. 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.

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pp 60-65

1978

Transportation Research Record

030902840X

Print

Figures (7) ; References (2)

Ballast (Railroads); Construction scheduling; Freight cars; Information processing; Instrumentation; Mechanical properties; Performance tests; Railroad rails; Rolling contact; Statistical analysis; Steering; Train track dynamics; Vehicle components; Vehicle dynamics; Wear; Wheels

Transportation Technology Center

Performance analysis

Bridges and other structures; Data and Information Technology; Highways; Railroads; Vehicles and Equipment

TRIS, TRB

Sep 29 1979 12:00AM

• ANALYTICAL AND EXPERIMENTAL STUDY OF RESIDUAL STRESS IN RAILS
• BALLAST AND SUBGRADE RESPONSE TO TRAIN LOADS
• DEVELOPMENT OF MULTILAYER ANALYSIS MODEL FOR TIE-BALLAST TRACK STRUCTURES
• EFFECTS OF ENERGY-COST VARIATION ON FEASIBILITY OF ELECTRIFYING THE CINCINNATI-ATLANTA MAIN LINE OF THE SOUTHERN RAILWAY SYSTEM
• INTRODUCTION TO STRESSES IN RAILS: STRESSES IN MIDRAIL REGIONS
• MATHEMATICAL MODEL FOR LATERAL THERMAL BUCKLING AND DISPLACEMENT OF CURVED TRACK
• PERMANENT-DEFORMATION BEHAVIOR OF RAILWAY BALLAST
• PREDICTION OF FATIGUE CRACK GROWTH IN RAILROAD RAILS
• STATISTICAL DESCRIPTION OF SERVICE LOADS FOR CONCRETE CROSSTIE TRACK