Under the direction of the Association of American Railroads Vehicle/Track System Committee, a laboratory test qualification formula/specification for locomotive-based top-of-rail (TOR) friction modifier application system hardware has been developed. This document describes the development and demonstration process, including measurement of the vibration field environment and an initial test of one TOR component in a laboratory vibration and thermal test. Revenue service onboard locomotive vibration environment was measured continuously during two tests in late-2001 and early-2002. The first test measured responses in a train hauling auto parts while the second measured responses in a train hauling coal. Results of the first simulation suggest that many of the issues experienced from over the road field tests, such as clogging and variable output due to temperatures, were simulated and reproduced in the laboratory simulation.
The operating dynamic clearance envelope has historically been a sum of estimated dimensional tolerances, sometimes even called “black magic” [1]. These tolerances exist by design within the car and the track, as well as between the wheel flanges and the rail gage face. Field observations of operating clearance have augmented these estimates. Recently a review of such expectations was desired as related to wide and/or tall payloads, with particular respect to train speed and track roughness. This project reexamines the factors affecting car body envelopes, including track curvature and elevation, and car parameters such as length, center of gravity (CG), and side bearing type. A particular goal of this study was to gain a rough understanding of the behavior expected relative to wide loads in the speed range of 30–50 mph. Both static analyses and dynamic negotiation of typical revenue track have been predicted. The NUCARS® multibody simulation software has been used to examine the influence of operating speed and FRA track class on the dynamic envelope. A summary of results is presented along with a discussion of general guidelines and additional considerations.
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