Effectiveness of alternative rail passenger equipment crashworthiness strategies

PDFProceedingsRTD2006-94043CrashworthinessImpact testsCollisionsPassenger carsCommuter carsCrash injury researchCrash victim simulationDummiesOccupant protection devicesVehicle compartmentsVehicle compartment componentsPush pull trainsUnited StatesAmerican Society of Mechanical EngineersInstitute of Electrical and Electronics EngineersJacobsen, KarinaSeverson, KristinePerlman, BenjaminJohn A. Volpe National Transportation Systems Center (U.S.)Tufts UniversityAGR-SAFETY AND SECURITY-SAFETY AND SECURITYNTL-RAIL TRANSPORTATION-Rail SafetyNTL-SAFETY AND SECURITY-AccidentsNTL-SAFETY AND SECURITY-Rail SafetyVolpe National Transportation Systems Center, Technical Reference CenterCrashworthiness strategies, which include crash energymanagement (CEM), pushback couplers, and push/pulloperation, are evaluated and compared under specific collisionconditions. Comparisons of three strategies are evaluated inthis paper:- Push versus Pull Operation (Cab Car Led versusLocomotive Led Consists)- Conventional versus CEM Consists- Incremental CEM versus Full-CEMRail cars that incorporate CEM are designed to absorb collisionenergy through crushing of unoccupied structures within thecar. Pushback couplers are designed to recede into the draft sillunder collision loads and enable the car ends to come intocontact, minimizing the likelihood of lateral buckling.Push/pull operation refers to operating either a locomotive (pullmode) or a cab car (push mode) at the leading end of the train.Five cases using combinations of these three strategies areevaluated. The basic collision scenario for each case analyzedin this paper is a train-to-train collision between like trains.Each train has a locomotive, four coach cars, and a cab car. Theimpact velocity ranges from 10 to 40 mph.The following five cases are evaluated:1. All conventional cars with a cab car leading (baselinecase)2. All conventional cars with a locomotive leading3. Conventional coach cars with pushback couplers, withCEM cab car leading4. All CEM cars with a cab car leading5. All CEM cars with a locomotive leadingA one-dimensional lumped-mass collision dynamics modelis used to evaluate the effectiveness of each strategy, orcombination of strategies, in terms of preserving survivablespace for occupants and minimizing secondary impact velocity(SIV). Test data is used to correlate SIV with head, chest, andneck injury. Probability of serious injuries and fatalities arecalculated based on calculated car crush and injury values. Themaximum crashworthy speed, or the maximum impact speed atwhich everyone is expected to survive, is calculated for eachcase.Of the five cases evaluated, the scenario of a cab car ledconventional consist represents the baseline level ofcrashworthiness. The highest levels of crashworthiness areachieved by a consist of all CEM cars with a locomotiveleading, followed by all CEM cars with a cab car leading. Theresults indicate that incremental improvements in collisionsafety can be made by judiciously applying differentcombinations of these crashworthiness strategies. A CEM cabcar leading conventional cars that are modified with pushbackcouplers enhances the level of crashworthiness over aconventional cab car led consist and provides a level ofcrashworthiness equal to a locomotive leading conventionalpassenger cars