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22 Appendix E Acknowledgment of Reviewers This report has been reviewed in draft form by persons chosen for their diverse perspectives and technical expertise in accordance with procedures approved by the NASEM Report Review Committee. The purposes of the independent review are to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institu- tional standards of objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. The commit- tee thanks the following individuals for their review of this report: Christopher Barkan, University of Illi- nois at UrbanaâChampaign; James O. Berger (NAS), Duke University; Grady Cothen, consultant; Peter Klauser, consultant; Kevin J. Renze, consultant; Walter Rosenberger, Norfolk Southern Corporation; John M. Samuels, Jr. (NAE), Revenue Variable Engineering, LLC; Roger R. Schmidt (NAE), International Business Machines Corporation; Howard A. Stone (NAS/NAE), Princeton University; and Terry Tse, Federal Railroad Administration (retired). Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the re- port before its release. The review of the report was overseen by the review coordinator, Susan Hanson (NAS), Clark University (emerita), and the review monitor, Robert Sproull (NAE), University of Massa- chusetts at Amherst. Appointed by NASEM, they were responsible for making certain that an independent examination of the report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of the report rests entirely with the committee and the institution.
Â 23 Appendix F DOT Analysis and Test Plan to Assess the Effectiveness of ECP Brakes in Reducing the Risks Associated with High-Hazard Flammable Trains [Brief notes, shown in italics, on the status of each item as of August 3, 2017, were provided by Kevin Kesler, DOT.] 1. INTRODUCTION Section 7311(b) of the Fixing Americaâs Surface Transportation Act (FAST Act) directs the Secre- tary of the Department of Transportation (DOT) to conduct tests to provide data to inform a review of the costs, benefits, and effects of electronically controlled pneumatic (ECP) brakes that were used in the Reg- ulatory Impact Analysis (RIA) for the âEnhanced Tank Car Standards and Operational Control for High- Hazard Flammable Trainsâ final rule (HHFT Rule; 80 FR 26643) published on May 8, 2015. DOT devel- oped this analysis and test plan to provide the necessary data to allow the Secretary to determine if ECP brakes are justified. The plan involves additional analysis (including computer simulation) and full-scale, physical tests. DOT has contracted with the Transportation Research Board (TRB) of the National Academy of Sciences (NAS) to provide independent oversight of the planned analysis and test work. TRB has formed a committee of experts to: 1. Familiarize itself with the analysis and testing that DOT relied upon for the HHFT Rule; 2. Review the detailed test and analysis plan DOT proposes and, in a letter report, confirm it meets the FAST Actâs requirement to âobjectively, accurately, and reliably measure the performance of ECP brake systems relative to other braking technologies or systems, such as distributed power and 2-way end-of-train devicesâ or recommend changes; 3. Review and oversee the testing procedures used by DOT or its contractors; 4. Review the test reports provided by DOT following the completion of testing and hold an open meeting to discuss the results; and 5. Provide a final letter report to DOT analyzing results of the testing and making findings and conclu- sions. The output from the analysis and testing described in this plan will be a series of reports describing methods and results. DOT will use the results, once confirmed by the TRB committee, to update the dis- cussion of ECP brakes in the RIA for the HHFT Rule. DOT has contracted with suppliers to conduct the analysis and testing specified in this plan. Some of the tests are to be conducted at the Federal Railroad Administrationâs (FRAâs) Transportation Technology Center in Pueblo, Colorado, due to the unique testing infrastructure available at the facility.
24 2. ANALYSIS PLAN 2.1 Coefficient of Friction-(Post derailment tank car kinetic energy dissipation) The HHFT RIA used results of computer models of tank cars sliding along the ground after derail- ment until they came to rest or collided with another tank car. DOT will test the sensitivity of the benefits of ECP brake benefits to different values of coefficient of friction between the tank car and the ground. The range of values of coefficient of friction used in this sensitivity test will be based [on] the results of full-scale tank car sliding tests on different ground conditions (specified later in this plan). The above plan was not executed, as the NAS committee did not suggest that this was critical to consider. 2.2 DOT-117 Puncture Resistance The HHFT RIA used a histogram of impact forces and the puncture resistance of different types of tank cars to calculate the number of punctures and to determine the benefits of ECP brakes. As part of meeting the FAST Act requirements, DOT will use a histogram of impact forces calculated using the structural properties (stiffness, mass, etc.) of a DOT-117 tank car and then applied to the calculated punc- ture resistance of the same type of car. DOT will calculate the puncture resistance, stiffness and other required properties of a DOT-117 tank car from a finite element model of the car. DOT will validate the model from full-scale impact tests (specified later in this plan). Test complete. Model was validated. Puncture predicted at 13 to 14 mph. Preliminary test results showed ânear punctureâ at 13.6 mph. Currently no plans for a second punc- ture test. 2.3 Curved Track DOT will calculate the benefits of ECP brakes on curved track that is representative of the distribu- tion of curves on the rail network. Several initial simulations were made which showed that this would not make a difference to brake system performance. Based on that and the renewed interest from the NAS committee on braking system profiles, this was not pursued further. 2.4 Derailment Initiation The HHFT RIA used the results of modeling with derailment initiated by a lateral force applied to the leading truck of the first car to be derailed. As part of meeting the FAST Act requirements, DOT will analyze alternative derailment initiation events to determine additional scenarios to the lateral force that was modeled for the HHFT RIA. Initiation events will include broken rails, broken wheels, bearing burn offs, wide gage, and track buckles. DOT will model the additional scenarios if they are found to be signif- icantly different in nature to an applied lateral force. Work initiated on this effort also indicated that mi- nor differences in the derailment force initiation would not have a large influence on the relative per- formance of brake systems. Therefore, focus was shifted to the items of specific interest to the NAS committee, including the brake system profiles and the multivariate analysis. 2.5 End-of-Train Device vs. Distributed Power DOT will compare the sequence of events in a derailment of a train fitted with an end-of-train de- vice to that of a train outfitted with distributed power at the front and rear. The events will include brake pipe pressure changes throughout the train, emergency brake applications and locomotive engineer re- sponses. These systems were compared as part of the test setups at both Conway and Watertown, and the result of the testing showed that performance differences were not significant, and that the perfor- mance of either system could be captured by one set of simulations.
Â 25 2.6 Model Validation DOT, with support of its contractors, will model a sample of previous derailments. DOT will com- pare the results from the modeling to what happened in real life. The comparison will include, but not be limited to, the number of punctures, distances traveled by cars from derailment to rest, the ratio of cars derailed to those that stay on the track, the ratio of head to side impacts and punctures. Preliminary re- sults were presented to the NAS committee on October 14, 2016. Additional validation efforts have been presented to the committee. 3. TEST PLANS The following are high level specifications for the planned tests. The contractor conducting each test will develop a detailed test plan as an early contract deliverable. 3.1 Coefficient of Friction-(Post derailment tank car kinetic energy dissipation) The contractor will perform a full-scale test to determine the coefficient of sliding friction between a tank car and the ground. The contractor will perform testing with the tank car on its side. The contractor will repeat the test on a variety of different ground conditions including those representing wet, dry and frozen agricultural land, and ballast. This plan was not executed, as the focus of the NAS committee dis- cussion changed to other issues. 3.2 DOT-117 Puncture Resistance The contractor will conduct full-scale impact tests to provide data to validate the computer model of a DOT-117 tank car. The tests will be conducted against the crash wall at FRAâs Transportation Technol- ogy Center in Pueblo, Colorado. The contractor may perform two tests: one that does not cause puncture and one that does. Test completeâ¦preliminary results appear to validate simulations.