Heavy-duty railcars carry greater than typical payloads by employing additional wheelsets to lessen wheel/rail contact stresses. Rather than the common 4-axle designs, these cars may have up to 16 axles supporting one deck. Traditionally, these car types have not performed as well as desired. As a response, designers have created depressed center body styles to lower the overall center-of-gravity (CG) height. Such designs lead to more complexity and expense. In this investigation, a heavy-duty 8-axle flatcar has been modeled, both with a flat carbody and a depressed body style. Simulations of harmonic roll perturbations were performed using various CG heights, track perturbation wavelengths and operating speeds. Results include comparisons of design versus performance trade-offs.

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Kasgro Company’s listing and drawings of their heavy-duty car fleet, 05/2006. http://www.triarchy.com/kasgro/specs.asp
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Association of American Railroads, 2003, Manual of Standards and Recommended Practices (MSRP), “Truck Performance Specification for Railcars,” Specification M-976, Washington, DC.
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Association of American Railroads, 1993, Manual of Standards and Recommended Practices, Part C, Volume II, Chapter XI, Service-Worthiness Tests for New Freight Cars, Washington, DC.
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