02-05-2011, 03:08 PM
ABSTRACT
In support of the Federal Railroad Administration’s (FRA)Railroad Equipment Safety Program, a full-scale dynamic testof a collision post of a state-of-the-art (SOA) end frame wasconducted on April 16, 2008. The purpose of the test was toevaluate the dynamic method for demonstrating energyabsorption and graceful deformation of a collision post.The post aims to protect the operators and passengers inthe event of a collision where only the superstructure, not theunderframe, is loaded. Methods for improving the performanceof collision and corner posts were prompted by accidents suchas the fatal collision in Portage, Indiana in 1998, where a coilof steel sheet metal penetrated the cab car through the collisionpost.The improvements made for the SOA end frame structureinclude more substantial corner and collision posts, robust postconnections to the buffer beam and anti-telescoping (AT) beam,and corner and collision posts integrated with a shelf andbulkhead sheet. Full length side sills improved support for theend frame. This test focused on one collision post because of itscritical position in protecting the operator and passengers in animpact with an object at a grade-crossing.For the test, a 14,000-lb cart impacted a standing cab car ata speed of 18.7 mph. The cart had a rigid coil shape mountedon the leading end that concentrated the impact load on thecollision post. The requirements for protecting the operator’sspace state that there will be no more than 10 inches oflongitudinal crush and none of the attachments of any of thestructural members separate.During the test, the collision post deformed approximately7.4 inches and absorbed approximately 138,000 ft-lb of energy.The attachment between the post and the AT beam remainedintact. The connection between the post and the buffer beamdid not completely separate, however the forward flange andboth side webs fractured. The post itself did not completelyfail. There was material failure in the back and the sides of thepost at the impact location. Overall, the end frame wassuccessful in absorbing energy and preserving space for theoperators and the passengers.
INTRODUCTION
As a result of consideration of both a notice of proposedrulemaking (NPRM) for improved cab car multiple unit (MU)locomotive equipment and the accepted industry standard, aseries of tests were planned to demonstrate examples ofconducting such tests to shows equivalence between testingprotocols. Three test scenarios are taken from the FRA’sproposed rule [1]. This paper covers the dynamic test of acollision post. There are two quasi-static tests also beingplanned. The quasi-statics tests are on the collision post and thecorner post.Both the proposed rule and the industry standard improvecrashworthiness performance due to increased static loadrequirements, as well as minimum energy absorption andmaximum allowable intrusion into the cab. By encouragingimproved energy absorption capabilities for the end frames, therule aims to improve survivability for operators and passengersat higher collision speeds.This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.Approved for public release; distribution is unlimited.
BACKGROUND:
COLLISION INVESTIGATIONSCollision Loading Scenarios Full-scalecrashworthiness research has focused on two generic loadingscenarios. In one scenario, a leading cab car hits another trainhead on. In this scenario both the underframe and thesuperstructure of the cab car are loaded.In a second scenario, a leading cab car hits an object at agrade crossing in such a manner that the superstructure isloaded, but the underframe is not. Since the underframe of arailcar provides the greatest strength to protect passengers, thisscenario can be dangerous for operators and passengers if theend frame is breached by the object.The series of end frame tests discussed in this paper focuson demonstrating the performance of end frame structures foran impact scenario similar to a grade crossing collision. Twocollisions are described which highlight the need for improvingend frame requirements for cab cars and MUs.Collision in Portage, Indiana On June 18, 1998, a cab carled,two-car MU commuter train collided with a highway truckat a grade crossing [2]. The highway truck consisted of a tractorwith two trailers. The trailers were loaded with coils of sheetsteel. The second trailer, the one furthest from the tractor, wasstopped on the tracks. The train collided with the second trailer,and during the impact, a coil of steel broke free and puncturedthe end of the car. The steel coil rolled down half the length ofthe car and killed three people [3].Figure 1 shows the exterior and the interior of the cab carafter the collision. The picture on the right shows the interior ofthe car. The collision post had been severed and pushed backinto the car. Figure 2 shows the 6-foot diameter, 19-ton steelcoil. This grade crossing collision is significant because the coilloaded the superstructure of the car, not the underframe.
Figure 1. Cab car involved in the grade crossing collision inPortage, IndianaFigure
2. Steel coil involved in the grade crossing collisionin Portage, IndianaCollision in Selma, North Carolina
On May 16, 1994,an overhanging intermodal trailer on the northbound freighttrain was obstructing the way of the southbound intercitypassenger train [2]. The forward trailer of the 51st car wasoverhanging the southbound track and engaged the leadlocomotive of the passenger train. At the onset of contact, thetrailer was above the deck and offset outside the collision postsof the passenger train lead locomotive. One operator was killedand another operator was injured during the collision.This collision is significant because the trailer impacted thesuperstructure of the car, not the underframe.
PASSENGER CRASHWORTHINESS PROGRAM
An ongoing objective has been to evaluate the existingpassenger car designs and offer potential improvements. Therehave been three full-scale dynamic tests with a grade-crossingscenario. Two tests focused on the corner post, testing ageneralized 1990s design and an improved SOA design. Thistest focused on the collision post of a SOA collision post.
State-of-the-Art End Frame
The SOA end frame is aspecific end frame prototype design developed for this series oftests. There are several improvements over the 1990s design.These improvements are intended to absorb more energyduring a collision and provide a survivable space for theoperator and passengers. The SOA design, shown in Figure 3,includes more substantial collision and corner posts. Theconnections between the corner and collision posts and the ATbeam along the top of the end frame, and the buffer beam alongthe bottom of the end frame, are made stronger by running theposts through the entire beams. Shelves and bulkhead sheetsconnect the collision and corner posts, allowing some load tobe shared between the two posts. The end frame is bettersupported by a continuous side sill and robust roof rails [4, 5].3Buffer BeamBulkheadSide SillRoofConnectionCollision PostAT PlateCorner PostShelf
Figure 3. Schematic of the state-of-the-art end frameTest Program
Table 1 shows the full-scale tests that havebeen performed as part of the grade-crossing scenario research.Two dynamic tests were performed on the corner posts. Onetest was performed on a 1990s design, which was designed tobe a typical end frame structure of the 1990s. The seconddynamic corner post test was conducted on a SOA design.This paper discusses the dynamic test of the collision postof the SOA end frame. Two more quasi-static tests are plannedon the state-of-the-art end frame, one on the collision post andone on the corner port. These tests are planned for the summerof 2008.
download full report
http://volpe.dot.gov/sdd/docs/2008/08-74020.pdf
In support of the Federal Railroad Administration’s (FRA)Railroad Equipment Safety Program, a full-scale dynamic testof a collision post of a state-of-the-art (SOA) end frame wasconducted on April 16, 2008. The purpose of the test was toevaluate the dynamic method for demonstrating energyabsorption and graceful deformation of a collision post.The post aims to protect the operators and passengers inthe event of a collision where only the superstructure, not theunderframe, is loaded. Methods for improving the performanceof collision and corner posts were prompted by accidents suchas the fatal collision in Portage, Indiana in 1998, where a coilof steel sheet metal penetrated the cab car through the collisionpost.The improvements made for the SOA end frame structureinclude more substantial corner and collision posts, robust postconnections to the buffer beam and anti-telescoping (AT) beam,and corner and collision posts integrated with a shelf andbulkhead sheet. Full length side sills improved support for theend frame. This test focused on one collision post because of itscritical position in protecting the operator and passengers in animpact with an object at a grade-crossing.For the test, a 14,000-lb cart impacted a standing cab car ata speed of 18.7 mph. The cart had a rigid coil shape mountedon the leading end that concentrated the impact load on thecollision post. The requirements for protecting the operator’sspace state that there will be no more than 10 inches oflongitudinal crush and none of the attachments of any of thestructural members separate.During the test, the collision post deformed approximately7.4 inches and absorbed approximately 138,000 ft-lb of energy.The attachment between the post and the AT beam remainedintact. The connection between the post and the buffer beamdid not completely separate, however the forward flange andboth side webs fractured. The post itself did not completelyfail. There was material failure in the back and the sides of thepost at the impact location. Overall, the end frame wassuccessful in absorbing energy and preserving space for theoperators and the passengers.
INTRODUCTION
As a result of consideration of both a notice of proposedrulemaking (NPRM) for improved cab car multiple unit (MU)locomotive equipment and the accepted industry standard, aseries of tests were planned to demonstrate examples ofconducting such tests to shows equivalence between testingprotocols. Three test scenarios are taken from the FRA’sproposed rule [1]. This paper covers the dynamic test of acollision post. There are two quasi-static tests also beingplanned. The quasi-statics tests are on the collision post and thecorner post.Both the proposed rule and the industry standard improvecrashworthiness performance due to increased static loadrequirements, as well as minimum energy absorption andmaximum allowable intrusion into the cab. By encouragingimproved energy absorption capabilities for the end frames, therule aims to improve survivability for operators and passengersat higher collision speeds.This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.Approved for public release; distribution is unlimited.
BACKGROUND:
COLLISION INVESTIGATIONSCollision Loading Scenarios Full-scalecrashworthiness research has focused on two generic loadingscenarios. In one scenario, a leading cab car hits another trainhead on. In this scenario both the underframe and thesuperstructure of the cab car are loaded.In a second scenario, a leading cab car hits an object at agrade crossing in such a manner that the superstructure isloaded, but the underframe is not. Since the underframe of arailcar provides the greatest strength to protect passengers, thisscenario can be dangerous for operators and passengers if theend frame is breached by the object.The series of end frame tests discussed in this paper focuson demonstrating the performance of end frame structures foran impact scenario similar to a grade crossing collision. Twocollisions are described which highlight the need for improvingend frame requirements for cab cars and MUs.Collision in Portage, Indiana On June 18, 1998, a cab carled,two-car MU commuter train collided with a highway truckat a grade crossing [2]. The highway truck consisted of a tractorwith two trailers. The trailers were loaded with coils of sheetsteel. The second trailer, the one furthest from the tractor, wasstopped on the tracks. The train collided with the second trailer,and during the impact, a coil of steel broke free and puncturedthe end of the car. The steel coil rolled down half the length ofthe car and killed three people [3].Figure 1 shows the exterior and the interior of the cab carafter the collision. The picture on the right shows the interior ofthe car. The collision post had been severed and pushed backinto the car. Figure 2 shows the 6-foot diameter, 19-ton steelcoil. This grade crossing collision is significant because the coilloaded the superstructure of the car, not the underframe.
Figure 1. Cab car involved in the grade crossing collision inPortage, IndianaFigure
2. Steel coil involved in the grade crossing collisionin Portage, IndianaCollision in Selma, North Carolina
On May 16, 1994,an overhanging intermodal trailer on the northbound freighttrain was obstructing the way of the southbound intercitypassenger train [2]. The forward trailer of the 51st car wasoverhanging the southbound track and engaged the leadlocomotive of the passenger train. At the onset of contact, thetrailer was above the deck and offset outside the collision postsof the passenger train lead locomotive. One operator was killedand another operator was injured during the collision.This collision is significant because the trailer impacted thesuperstructure of the car, not the underframe.
PASSENGER CRASHWORTHINESS PROGRAM
An ongoing objective has been to evaluate the existingpassenger car designs and offer potential improvements. Therehave been three full-scale dynamic tests with a grade-crossingscenario. Two tests focused on the corner post, testing ageneralized 1990s design and an improved SOA design. Thistest focused on the collision post of a SOA collision post.
State-of-the-Art End Frame
The SOA end frame is aspecific end frame prototype design developed for this series oftests. There are several improvements over the 1990s design.These improvements are intended to absorb more energyduring a collision and provide a survivable space for theoperator and passengers. The SOA design, shown in Figure 3,includes more substantial collision and corner posts. Theconnections between the corner and collision posts and the ATbeam along the top of the end frame, and the buffer beam alongthe bottom of the end frame, are made stronger by running theposts through the entire beams. Shelves and bulkhead sheetsconnect the collision and corner posts, allowing some load tobe shared between the two posts. The end frame is bettersupported by a continuous side sill and robust roof rails [4, 5].3Buffer BeamBulkheadSide SillRoofConnectionCollision PostAT PlateCorner PostShelf
Figure 3. Schematic of the state-of-the-art end frameTest Program
Table 1 shows the full-scale tests that havebeen performed as part of the grade-crossing scenario research.Two dynamic tests were performed on the corner posts. Onetest was performed on a 1990s design, which was designed tobe a typical end frame structure of the 1990s. The seconddynamic corner post test was conducted on a SOA design.This paper discusses the dynamic test of the collision postof the SOA end frame. Two more quasi-static tests are plannedon the state-of-the-art end frame, one on the collision post andone on the corner port. These tests are planned for the summerof 2008.
download full report
http://volpe.dot.gov/sdd/docs/2008/08-74020.pdf