Proceedings of the Joint Rail Conference, April 2-4, 2014, Colorado Springs, CO.

PDFIn ProceedingsJRC2014-3872Railroad tracksStandardsSafetyRailroad safetyVehicle dynamicsTrain track dynamicsRolling contactSuspension systemsUnited StatesAmerican Society of Mechanical EngineersInstitute of Electrical and Electronics EngineersAmerican Society of Civil EngineersMarquis, BrianLeBlanc, JonTajaddini, AliJohn A. Volpe National Transportation Systems Center (U.S.)United States. Federal Railroad Administration. Office of Research and DevelopmentAGR-SAFETY AND SECURITY-SAFETY AND SECURITYNTL-RAIL TRANSPORTATION-RAIL TRANSPORTATIONNTL-RAIL TRANSPORTATION-Rail SafetyNTL-SAFETY AND SECURITY-Vehicle DesignNTL-SAFETY AND SECURITY-SAFETY AND SECURITYNTL-SAFETY AND SECURITY-Rail SafetyVolpe National Transportation Systems Center, Technical Reference CenterVehicle/Track Interaction (VTI) Safety Standards aim toreduce the risk of derailments and other accidents attributableto the dynamic interaction between moving vehicles and thetrack over which they operate. On March 13, 2013, the FederalRailroad Administration (FRA) published a final rule titled\ue2\u20ac\u153Vehicle/Track Interaction Safety Standards; High-Speed andHigh Cant Deficiency Operations\ue2\u20ac? which amended the TrackSafety Standards (49 CFR Part213) and the PassengerEquipment Safety Standards (49 CFR Part 238) in order topromote VTI safety under a variety of conditions at speeds upto 220 mph. Among its main accomplishments, the final rulerevises standards for track geometry and enhances qualificationprocedures for demonstrating vehicle trackworthiness to takeadvantage of computer modeling.The Track Safety Standards provide safety limits formaximum allowable track geometry variations for all nine FRATrack Classes \ue2\u20ac\u201d i.e., safety \ue2\u20ac\u153minimums.\ue2\u20ac? These limits serve toidentify conditions that require immediate attention becausethey may pose or create a potential safety hazard. While theseconditions are generally infrequent, they define the worstconditions that can exist before a vehicle is required to slowdown. To promote the safe interaction of rail vehicles with thetrack over which they operate (i.e. wheels stay on track, andvehicle dynamics do not overload the track structure, vehicleitself, or cause injury to passengers), these conditions must beconsidered in the design of suspension systems. In particular,rail vehicle suspensions must be designed to control thedynamic response such that wheel/rail forces and vehicleaccelerations remain within prescribed thresholds (VTI safetylimits) when traversing these more demanding track geometryconditions at all allowable speeds associated with at particulartrack class.To help understand the differences in performancerequirements (design constraints) being placed on the design ofpassenger equipment suspensions throughout the world,comparisons have been made between FRA safety standardsand similar standards used internationally (Europe, Japan, andChina) in terms of both allowable track geometry deviationsand the criteria that define acceptable vehicle performance(VTI safety limits). While the various factors that haveinfluenced the development of each of the standards are notreadily available or fully understood at this time (e.g.,economic considerations, provide safety for unique operatingconditions, promote interoperability by providing a railwayinfrastructure that supports a wide variety of rail vehicle types,etc.), this comparative study helps to explain in part why, incertain circumstances, equipment that has been designed foroperation in other parts of the world has performed poorly, andin some cases had derailment problems when imported to theU.S. Furthermore, for specific equipment that is notspecifically designed for operation in the U.S., it helps toidentify areas that may need to be addressed with otherappropriate action(s) to mitigate potential safety concerns, suchas by ensuring that the track over which the equipment isoperating is maintained to standards appropriate for the specificequipment type, or by placing operational restrictions on theequipment, or both.In addition to these comparisons, an overview of the newFRA qualification procedures which are used for demonstratingvehicle trackworthiness is provided in this paper. Theseprocedures, which include use of simulations to demonstratedynamic performance, are intended to give guidance to vehicledesigners and provide a more comprehensive tool for safetyassessment and verification of the suitability of a particula