Source: https://ntsb.gov/safety/safety-recs/_layouts/ntsb.recsearch/Recommendation.aspx?Rec=R-04-007
Timestamp: 2019-06-16 06:33:58
Document Index: 660655449

Matched Legal Cases: ['§ 172', '§ 173', 'arts 171', '§ 179', '§ 179', '§ 179', 'arts 100']

Safety Recommendation R-04-007
Synopsis: At approximately 1:37 a.m. on January 18, 2002, eastbound Canadian Pacific Railway (CPR) freight train 292-16, traveling about 41 mph, derailed 31 of its 112 cars about 1/2 mile west of the city limits of Minot, North Dakota. Five tank cars carrying anhydrous ammonia, a liquefied compressed gas, catastrophically ruptured, and a vapor plume covered the derailment site and surrounding area. The conductor and engineer were taken to the hospital for observation after they complained of breathing difficulties. About 11,600 people occupied the area affected by the vapor plume. One resident was fatally injured, and 60 to 65 residents of the neighborhood nearest the derailment site were rescued. As a result of the accident, 11 people sustained serious injuries, and 322 people, including the 2 train crewmembers, sustained minor injuries. Damages exceeded $2 million, and more than $8 million has been spent for environmental remediation.
Recommendation: TO THE FEDERAL RAILROAD ADMINISTRATION: Develop and implement tank car design-specific fracture toughness standards, such as a minimum average Charpy value, for steels and other materials of construction for pressure tank cars used for the transportation of U.S. Department of Transportation class 2 hazardous materials, including those in "low temperature" service. The performance criteria must apply to the material orientation with the minimum impact resistance and take into account the entire range of operating temperatures of the tank car.
Accident #: DCA-02-MR-002
Report #: RAR-04-01
Accident Date: 1/18/2002
Date Closed: 2/14/2019
Addressee(s) and Addressee Status: FRA (Closed - Acceptable Action/Superseded)
Response: On February 11, 2019, we adopted our report, Rupture of a DOT-105 Rail Tank Car and Subsequent Chlorine Release at Axiall Corporation, New Martinsville, West Virginia, August 27, 2016, NTSB/HZM-19/01. The details of this accident investigation and the resulting safety recommendations may be found in the attached report, which can also be accessed at http://www.ntsb.gov. This report includes Safety Recommendation R-19-1 to the Pipeline and Hazardous Materials Safety Administration (PHMSA), which supersedes Safety Recommendation R-04-7. Additional information regarding these recommendations can be found in section 2.1.1 of the New Martinsville accident report. Because we have issued Safety Recommendation R-19-1 to PHMSA, Safety Recommendation R-04-7 is classified CLOSESD--ACCEPTABLE ACTION/ SUPERSEDED. The NTSB also addressed problems with pre-1989 pressure tank cars in the investigation of the Minot accident (NTSB 2004). NTSB investigators conducted metallurgical examinations of nonnormalized steel from five pre-1989 specification DOT-105 tank cars involved in that accident. The NTSB concluded “the low fracture toughness of the nonnormalized steels used for the tank shells of five tank cars that catastrophically failed in the accident contributed to their complete fracture and separation.” Consequently, the NTSB expressed concern about safely transporting liquefied compressed gases in pressure tank cars constructed before 1989, given the high volume of hazardous materials transported in these tank cars and their lengthy service lives. As a result, the NTSB issued the following safety recommendations to the FRA: Conduct a comprehensive analysis to determine the impact resistance of the steels in the shells of pressure tank cars constructed before 1989. At a minimum, the safety analysis should include the results of dynamic fracture toughness tests and/or the results of nondestructive testing techniques that provide information on material ductility and fracture toughness. The data should come from samples of steel from the tank shells from original manufacturing or from a statistically representative sampling of the shells of the pre-1989 pressure tank car fleet. (R-04-4) This recommendation is classified Closed?Unacceptable Action. Based on the results of the Federal Railroad Administration’s comprehensive analysis to determine the impact resistance of the steels in the shells of pressure tank cars constructed before 1989, as addressed in Safety Recommendation R-04-4, establish a program to rank those cars according to their risk of catastrophic fracture and separation and implement measures to eliminate or mitigate this risk. This ranking should take into consideration operating temperatures, pressures, and maximum train speeds. (R-04-5) This recommendation is classified Closed?Unacceptable Action. Develop and implement tank car design-specific fracture toughness standards, such as a minimum average Charpy value, for steels and other materials of construction for pressure tank cars used for the transportation of U.S. Department of Transportation Class 2 hazardous materials, including those in low-temperature service. The performance criteria must apply to the material orientation with the minimum impact resistance and take into account the entire range of operating temperatures of the tank car. (R-04-7) This recommendation is classified Open?–Acceptable Response. On January 13, 2009, PHMSA published final rule HM-246, which included a new provision in 49 CFR 173.31(e)(2)(v) that required a tank car owner, when retiring or removing tank cars transporting PIH/TIH materials, to select a tank car constructed of nonnormalized steel (pre-1989 construction) over a tank car constructed of normalized steel (Federal Register 2009, 1770). PHMSA stated in the preamble to this rule that although it considered the rule responsive to the NTSB, the rule did not directly implement Safety Recommendations R-04-4 or -5. On August 19, 2010, the NTSB responded to the FRA that even though the new provision may result in pre-1989 tank cars that transport PIH/TIH materials being retired somewhat earlier than other pre-1989 tank cars, this was not an acceptable alternative to the recommended actions. In response to Safety Recommendation R-04-7, on May 16, 2016, the FRA notified the NTSB that it had developed a list of regulated Class 2 hazardous materials and would obtain data related to their actual shipment conditions (e.g., temperature of the material at loading and the pressure in the tank car at loading). FRA stated that, based on this analysis, it will develop a list of Class 2 materials with shipping temperatures above the cryogenic temperature (-90? or -130?) and below the ambient temperature. FRA stated it will use this list to ensure that pressure cars carrying Class 2 hazardous materials within this temperature range and at elevated pressures will be required to have the tank car steels conform to the requirements of AAR’s Manual of Standards and Recommended Practices (MSRP), Section 2.2.1.2. AAR’s specification requires steel used for both the shell and the heads of pressure tank cars be tested with a Charpy impact test at -30? (-36.4?) for steel coupons with the rolling direction normal to the test direction. AAR’s specification also requires the test to be conducted at -50? (-45.6?) with coupons rolled in the direction of the test. The FRA stated that in a future rulemaking, it and PHMSA will incorporate provisions into the Hazardous Materials Regulations referencing the 2014 edition of the AAR’s MSRP and identifying the “low-temperature” commodities. The NTSB concludes that PHMSA’s failure to establish a final tank car specification for PIH/TIH tank cars and an aggressive schedule for removing nonconforming tank cars from service creates a disincentive to timely fleet modernization. Therefore, the NTSB recommends that PHMSA promulgate a final standard for pressure tank cars used to transport PIH/TIH materials that includes enhanced fracture toughness requirements for tank heads and shells. This new safety recommendation supersedes Safety Recommendation R-04-7 to the FRA. Therefore, Safety Recommendation R-04-7, classified Open––Acceptable Response under previous NTSB actions in this report (Safety Issues section) is reclassified CLOSED--ACCEPTABLE ACTION/ SUPERSEDED.
Response: -From Ronald L. Batory, Administrator: The NTSB issued this recommendation in response to the January 18, 2002, derailment of Canadian Pacific Railway cars near Minot, North Dakota, that resulted in five ruptured tank cars and the release of a vapor plume into the surrounding area. Develop and implement tank car design-specific fracture toughness standards, such as a minimum average Charpy value, for steels and other materials of construction for pressure tank cars used for the transportation of US. Department of Transportation Class 2 hazardous materials, including those in "low temperature " service. The performance criteria must apply to the material orientation with the minimum impact resistance and take into account the entire range of operating temperatures of the tank car. On June 24, 2005, the Association of American Railroads (AAR) revised its Specification for Tank Cars (Chapter 2, Section 2.2.1.2, General Requirements) to require Charpy testing for steel used in the construction of pressure tank cars used to transport Class 2 low temperature materials. This requirement was effective for all pressure cars ordered after August 1, 2005. AAR's actions effectively addressed Safety Recommendation R-04-07. FRA has recommended to the Pipeline and Hazardous Materials Safety Administration (PHMSA) that it update the incorporation by reference of AAR's Specification for Tank Cars in the Federal hazardous materials regulations to enforce the AAR standard addressing this recommendation. FRA does not have the authority to amend PHMSA's regulations, and FRA has taken all steps it can within its authority to address this recommendation. Accordingly, FRA respectfully asks the NTSB to classify recommendation R-04-07 as "Closed- Acceptable Action."
Response: -From Sarah E. Feinberg, Administrator: This letter is to update you on the status of the Federal Railroad Administration's (FRA) responses to certain National Transportation Safety Board (NTSB) Safety Recommendations (R-01-02 R-04-07 R-05-17 R-07-02 R-08-12 R-14-02 R-14-16 and R-14-17) issued to the FRA. In the enclosure, FRA responds to these Safety Recommendations and explains the actions it has taken in response to them. FRA's actions, once implemented, will satisfy the intent of these open NTSB recommendations and FRA will keep the NTSB informed of their completion. FRA created a table of each Class 2 hazardous material listed in the Hazardous Materials Table in 49 CFR § 172.101 with a unique United Nations (UN) identified number. For each material listed, the table includes the melting and boiling points at atmospheric pressure. FRA will analyze the data in this table relating to the hazardous material that is transported in a tank car as the bulk package. ( 49 CFR § § 173.318 and 173 .319). In addition, FRA will obtain data-related to the actual shipment conditions of the identified materials (e.g., temperature of the material at loading and the pressure in the tank car at loading). Based on this analysis, FRA will develop a list of Class 2 materials with shipping temperatures above the cryogenic temperature (-90degrees Centigrade (C) or -130 degrees Fahrenheit (F)) and below the ambient temperature. FRA will use this list to ensure all references to requirements for Charpy tests are applied to the "low-temperature" Class 2 commodities identified. The pressure cars that carry any Class 2 material with shipping temperatures in this range (i.e., any "low-temperature" commodity) at elevated pressures will be required to have the tank car steels conform to the requirements of AAR's Specification for Tank Cars M-1002, Section 2.2.1.2. AAR's specification requires steel, used for both the shell and the head of pressure tank cars, be tested with a Charpy notch test at -30 degrees F (-36.4 degrees C) for steel coupons with the roll direction normal to the test direction. AAR' s Specification also requires the test to be conducted at -50 degrees F (-45.6 degrees C) with coupons rolled in the direction of the test. In a future rulemaking, FRA and PHMSA will add provisions to PHMSA's regulations incorporating by reference the 2014 edition of the AAR's Specification for Tank Cars M-1002 and identifying the "low-temperature" commodities.
Response: Although we are disappointed that more than 10 years have passed since we issued this recommendation without action being completed, we are somewhat encouraged that the FRA continues making progress toward its implementation. We note that you are working with the Pipeline and Hazardous Materials Safety Administration (PHMSA) on rulemaking that will incorporate the latest version of the M 1002, including these requirements. We also note that you plan to publish a report detailing the series of tests and subsequent materials analyses that you will evaluate to determine whether rulemaking is needed to change the requirements specified in the current hazardous materials rule. Pending timely implementation of the requested material property criteria into the tank car design standard, Safety Recommendation R 04-7 is classified OPEN—ACCEPTABLE RESPONSE.
Response: -From Joseph C. Szabo, Administrator: Currently, the U.S. Department of Transportation's (DOT) Hazardous Materials Regulations (HMR), found at Title 49 Code of Federal Regulations (CFR) Parts 171-180, specify the minimum values of tensile strength and elongation for all tank car steels (See, e.g., 49 CFR § 179.1 00-7). Further, for carbon dioxide, refrigerated liquid, vinyl fluoride, stabilized and hydrogen chloride, and refrigerated liquid, the HMR have requirements for Charpy V –notch testing of tank car steels (See 49 CFR § 179.102-1(a)). There is also a requirement for normalization of all tank car carbon steels (See, e.g., 49 CFR § 179.100-3(a)). The AAR's Specifications for Tank Cars (M-1002) have similar material property requirements. In addition, M-1002 requires Charpy impact tests for all steels used for pressure tank car shells and heads. FRA is working with Pipeline and Hazardous Materials Safety Administration (PHMSA) on a rulemaking that will incorporate the latest version ofthe M-1002 that will include these requirements, which exceed the material properties in the HMR. The research sponsored as part of the Advanced Tank Car Collaborative Research Project is ongoing. The results of the FRA -sponsored project, published in 2013, evaluates the puncture force and energy of indenters with a variety of shapes, sizes, and different impact scenarios, as well as the correlation of steel properties to puncture resistance. In a separate, but related, effort, FRA performed full-scale crash tests to validate the results of the aforementioned research. In December 2013, FRA funded a side impact puncture test of a DOT -Specification 111 tank car that was performed at the Transportation Technology Center in Pueblo, CO. This test was followed by another FRA-funded side impact puncture test of a DOT -Specification 112 tank car in February 2014. Following each test, a coupon of the tank shell was acquired and tested to determine the properties of the steel and validate the constitutive element of the model. A report will be published detailing the tests and results. The results of the tests and subsequent materials analyses will be evaluated to determine whether a rulemaking is needed to change the current requirements in the HMR. It should be noted that AAR, which delegated authority through the HMR to approve all tank car designs, has recently modified the tank car material standards in M-1002, to include fracture toughness requirements.
Response: Although we are not pleased that more than 10 years have passed since we issued this recommendation, we are encouraged that you intend to incorporate the Association of American Railroads’ specification requiring minimum fracture toughness values for tank car materials in low temperature service. Pending completion of your development and implementation of the requested material property criteria into the tank car design standard, Safety Recommendation R 04-7 is classified OPEN—ACCEPTABLE RESPONSE.
Response: -From Joseph C. Szabo, Administrator: Currently, the HMR, found at 49 CFR Parts 100-180, specify the minimum values of tensile strength and elongation for all tank car steels. Further, for carbon dioxide, refrigerated liquid, vinyl fluoride, stabilized and hydrogen chloride, and refrigerated liquid, the HMR have requirements for Charpy V-notch testing of tank car steels. There is also a requirement for normalization of all tank car carbon steels. The AAR's Specifications for Tank Cars (M-1002) have similar material property requirements. In addition, the M-1 002 requires Charpy impact tests for all steels used for pressure tank car shells and heads. FRA is working with PHMSA on a rulemaking that will incorporate the latest version of the M -1 002, which will include these requirements that exceed the material properties in the HMR. The research sponsored as part of the Advanced Tank Car Collaborative Research Project is ongoing. The results of the FRA-sponsored project, published in 2013, evaluates the puncture force and energy of indenters with a variety of shapes, sizes, and different impact scenarios, as well as the correlation of steel properties to puncture resistance. In a separate but related effort, FRA executed a plan to perform full-scale crash tests to validate the results of the aforementioned research. In December 2013, FRA funded a side impact puncture test of a DOT-111 specification tank car, at the Transportation Technology Center in Pueblo, Colorado. This test was followed by another FRA-funded side impact puncture test of a DOT-112 specification tank car in February 2014. Following each test, a coupon of the tank shell was acquired and tested to determine the properties of the steel and validate the constitutive element of the model. A report will be published detailing the tests and results.
Response: The last letter that we received from the FRA regarding Safety Recommendation R-04-1 was on May 20, 2009. On January 27, 2010, Safety Recommendation R-04-1 was classified “Open—Acceptable Response” pending revision of procedures to include nondestructive testing techniques for identifying cracks in rail joint bars. We reiterated this recommendation on July 6, 2006, as a result of our investigation of the June 28, 2004, accident in Macdona, Texas. The last letter that we received from the FRA regarding Safety Recommendation R-04-7 was on November 17, 2009. Safety Recommendation R-04-7 was classified “Open?Acceptable Response” on August 19, 2010, pending the development and implementation of tank car design specific fracture toughness standards. Because we have no evidence that the FRA has made any progress on these issues since 2009, pending an update from the FRA regarding them, Safety Recommendations R 04-1 and -7 are classified OPEN—UNACCEPTABLE RESPONSE.
Response: -From Ray LaHood, Secretary of the United States Department of Transportation: NTSB Classification and Actions Taken by FRA: Open – Acceptable Response. FRA, in conjunction with the Advanced Tank Car Collaborative Research Project (ATCCRP), is sponsoring research to evaluate the puncture force of impactors having a variety of sizes and shapes. In addition, the research will examine the effect of different impact scenarios such as location and angle of impact. The results of the research will be used to develop a puncture resistance performance standard as well as a standard methodology that all designers will use to evaluate their tank car designs. This will allow for a consistent and objective evaluation of submitted designs. Additionally, the industry, also in conjunction with the ATCCRP, is sponsoring research that will correlate steel properties to puncture resistance. This research will enable development of a battery of tests that will allow for the prediction of the behavior of particular steel in accident conditions. The improved constitutive relationships will increase the value of the simulation results. This research will begin early in 2011. Actions Needed to Be Taken by FRA: Continue research.
Response: CC# 2090704 does not address R-04-7.
Response: NMC# 103281: The NTSB notes (1) that the FRA has cooperated with the Association of American Railroads in developing minimum impact resistance standards for normalized steel that require minimum average Charpy value and (2) that Charpy tests be performed in the orientation of the sample material with the least impact resistance. The results of the FRA’s dynamic fracture toughness testing did not validate that any practical specification could be developed. The DOT is continuing to study the dynamic fracture toughness of steels and will incorporate any feasible tank car design standard into the hazardous materials regulations, as appropriate, in future rulemakings. Pending the development and implementation of tank car design-specific fracture toughness standards, Safety Recommendation R-04-7 is classified OPEN – ACCEPTABLE RESPONSE. We look forward to receiving updates as further progress is made to complete action to address Safety Recommendation R-04-7. Safety Recommendation R-05-16 was issued to the FRA as a result of the NTSB’s investigation of the collision of a Norfolk Southern Railway Company (NS) freight train with a standing NS local train and the subsequent release of hazardous materials at Graniteville, South Carolina, on January 6, 2005.
Response: MC# 2090655 does not address R-04-7.
Response: MC# 2090704 - From Joseph C. Szabo, Administrator: Field testing has been completed. The FRA and Volpe team presented a series of reports on the field testing (modeling research) at the American Society of Mechanical Engineers conference in Chicago on September 11,2007. As noted in R-04-06, the final research report prepared by Volpe was recently published. FRA plans to use that research to determine the appropriate course of action. FRA has preliminarily concluded that the results of the dynamic fracture toughness testing do not demonstrate that a workable steel specification could be developed. However, FRA is continuing to examine the dynamic fracture toughness of steels used in the construction of hazardous materials tank cars. The FRA respectfully requests NTSB classify this Safety Recommendation as "Open- Acceptable Response."
Response: Letter Mail Controlled 10/22/2009 3:09:01 PM MC# 2090655 - From John D. Porcari, Deputy Secretary of Transportation: The Department shares NTSB's concerns regarding the safe transportation of hazardous materials by railroad tank car. FRA's tank car research program continues to focus on the development of effective strategies to maintain tank integrity during train derailments and collisions. As noted in the final rule published by PHMSA on January 13, 2009 pertaining to improving the safety of railroad tank car transportation of hazardous materials (final rule), the Department recognizes that the rule did not directly implement each of the above-identified NTSB recommendations. The Department intended the final rule to be as responsive as possible to NTSB's recommendations related to tank car structural integrity (R-04-04, R-04-05,-04-06 and R-04-07) and operational measures related to the transportation of materials poisonous by inhalation (PIH) (R-05-16). However, as explained in the rule, given available technology, as well as practical and economic considerations, the rule is only the first part of a longer-term strategy to enhance the safety of rail tank car shipments of hazardous materials. Focusing on PIH materials, FRA's research program is designed (1) to further identify and understand the existing baseline risks associated with the transportation of hazardous material by rail tank car (e.g., how likely is a given tank car to be breached in the event of a collision or derailment), and (2) to determine the effect various regulatory changes underway will have on the identified risks. FRA will use these research results to determine how best to leverage industry and/or government efforts aimed at mitigating the identified risk. Meanwhile, however, FRA continues to focus effort on enhancing the ability to maintain tank integrity during accident conditions by potentially incorporating into tank cars crash energy management features and enhanced top fittings and valve protection. FRA is an active contributor to the Advanced Tank Car Collaborative Research Project (ATCCRP), a collaborative industry/government effort that is building on the work of the Next Generation Rail Tank Car Project discussed in detail in the preambles to both the NPRM and final rule. The ATCCRP is currently developing the appropriate memoranda of understanding, as well as a five year plan for supportive research. With regard to NTSB recommendation R-04-04, in August 2008 FRA published a report prepared by Southwest Research Institute (SRI) addressing the impact resistance of steels in the shells of pressure tank cars constructed before 1989 (i.e., cars constructed with non normalized steel). A CD copy of that report is enclosed. As a result of the findings of SWI's analysis, FRA has not identified a clear trend between chemical, tensile, or charpy v-notch toughness properties and tank car build dates. Accordingly, at this time, although FRA believes that material properties play an important role in the performance of tank cars subjected to fatigue type loading, for overload conditions such as those experienced in collisions or derailments, ERA does not believe that a ranking such as that recommended in R-04-05 will provide a useful tool for improving tank car performance. In addition, recognizing that cars constructed before 1989 utilizing non-normalized steel are reaching the upper limits of their useful lives and the extensive voluntary efforts well underway in industry to phase out these non-normalized steel cars, the Department's final rule requires car owners to prioritize the retirement or removal of pre-1989 non-normalized steel cars. The final rule also adopted the industry standard requiring newly constructed tank cars designed to transport PIH materials to be constructed of normalized steel. With regard to recommendation R-04-07, recommending that the Department develop and implement tank car design-specific fracture toughness standards, since June 2005, the Association of American Railroads, in cooperation with FRA, has developed standards that ensure a minimum level of impact resistance for normalized steel and that require that Charpy tests be performed in the orientation of the sample material with the lowest impact property. As explained in the preamble to the final rule, at this time, the results of FRA's dynamic fracture toughness testing does not demonstrate that a workable steel specification could be developed. Accordingly, the Department is continuing to examine the dynamic fracture toughness of steels used in the construction of hazardous materials pressure tank cars and will incorporate any workable tank car design-specific fracture toughness standards into the hazardous materials regulations as appropriate in future rulemaking.
Response: Notation 8027: The National Transportation Safety Board has reviewed the Pipeline and Hazardous Materials Safety Administration’s (PHMSA’s) notice of proposed rulemaking (NPRM), “Hazardous Materials: Improving the Safety of Railroad Tank Car Transportation of Hazardous Materials,” that was published at 73 Federal Register 17818 on April 1, 2008. The NPRM requested comments on proposed enhanced railroad tank car performance standards and operating restrictions that are designed to minimize the loss of lading from railroad tank cars transporting liquefied gases that are poisonous by inhalation (PIH), especially chlorine and anhydrous ammonia, in the event of an accident. These proposals include enhanced tank car performance standards for head and shell impacts, operational restrictions for trains hauling tank cars containing PIH materials, interim operational restrictions for trains hauling tank cars not meeting the enhanced performance standards, and an allowance to increase the gross weight of tank cars that meet the enhanced performance standards. This proposed rulemaking does not establish enhanced tank car performance standards for all pressure tank cars. For example, pressure tank cars transporting liquefied flammable gases, such as propane, would not be subject to the proposed improved performance standards. Overview Between 2002 and 2005, the Safety Board investigated three accidents that involved the failure of railroad tank cars and the release of PIH materials: (1) the January 18, 2002, derailment of a Canadian Pacific Railway freight train near Minot, North Dakota; (2) the June 28, 2004, collision of a Union Pacific Railroad freight train and a BNSF freight train in Macdona, Texas; and (3) the January 6, 2005, collision of a Norfolk Southern freight train with a standing local train in Graniteville, South Carolina. As a result of the Minot investigation, the Board issued the following four safety recommendations to the Federal Railroad Administration (FRA): R-04-4 Conduct a comprehensive analysis to determine the impact resistance of the steels in the shells of pressure tank cars constructed before 1989. At a minimum, the safety analysis should include the results of dynamic fracture toughness tests and/or the results of nondestructive testing techniques that provide information on material ductility and fracture toughness. The data should come from samples of steel from the tank shells from original manufacturing or from a statistically representative sampling of shells of the pre-1989 pressure tank car fleet. R-04-5 Based on the results of the Federal Railroad Administration’s comprehensive analysis to determine the impact resistance of the steels in shells of pressure tank cars constructed before 1989, as addressed in Safety Recommendation R-04-4, establish a program to rank those cars according to their risk of catastrophic fracture and separation and implement measures to eliminate or mitigate this risk. This ranking should take into consideration operating temperatures, pressures, and maximum train speeds. R-04-6 Validate the predictive model the Federal Railroad Administration is developing to quantify the maximum dynamic forces acting on railroad tank cars under accident conditions. R-04-7 Develop and implement tank car design-specific fracture toughness standards, such as minimum average Charpy value, for steels and other materials of construction for pressure tank cars used for the transportation of U.S. Department of Transportation class 2 hazardous materials, including those in low-temperature service. The performance criteria must apply to the material orientation with the minimum impact resistance and take into account the entire range of operating temperatures of the tank car. As a result of the Graniteville investigation, the Safety Board issued the following two safety recommendations to the FRA: R-05-15 Require railroads, in non-signaled territory and in the absence of switch position indicator lights or other automated systems that provide train crews with advance notice of switch positions, to operate those trains at speeds that will allow them to be safely stopped in advance of misaligned switches. R-05-16 Require railroads to implement operating measures, such as positioning tank cars toward the rear of trains and reducing speeds through populated areas, to minimize impact forces from accidents and reduce the vulnerability of tank cars transporting chlorine, anhydrous ammonia, and other liquefied gases designated as poisonous by inhalation. As a result of the Macdona accident, the Safety Board reiterated Safety Recommendations R-04-4 through -7 and R-05-16. The Safety Board supports the stated goals of the NPRM to improve the crashworthiness protection of railroad tank cars designed to transport PIH materials and believes that many of the proposed standards in the NPRM, when implemented, will significantly improve the safety of transporting PIH gases in railroad tank cars. The Safety Board notes that the NPRM will not apply to all pressure tank cars, such as those used to transport flammable gases like propane. The Board believes that the NPRM can be improved in several areas that we address below. Proposed Performance Standards for the Structural Integrity of Tank Cars The NPRM proposes that for a tank car transporting PIH gases, the standard for tank head puncture resistance will be increased from an 18-mph strike with a coupler to a 30-mph strike by a loaded freight car with a 6-inch-square cross-section ramming device that has the outer dimensions of a coupler with its knuckle removed. In addition, the NPRM also includes a proposed standard for tank shell puncture resistance that would require that the tank shell be capable of sustaining the impact of a 25-mph strike by a loaded freight car with a 6-inch-square cross-section ramming device. The current regulations do not include any standards addressing tank shell puncture resistance. These proposed performance standards for tank cars used for the transportation of PIH gases will improve the integrity and performance of the puncture resistance of such tank cars and thereby reduce the likelihood of a subsequent release of the PIH cargoes. However, the Safety Board does have concerns about the technical basis of these performance standards. The Board understands that the test speed chosen for the performance standard is based on the assumption that the impact speed of a freight car striking a tank car will be less than the speed of the train. The FRA said that Volpe National Transportation Systems Center (Volpe) research concluded that the speed at which freight cars hit after an accident’s initiation is about 50 percent of the train speed at the time of the accident. Therefore, a maximum 25-mph impact speed for secondary rail cars involved in an accident was proposed. The Board does not believe that 50 percent is applicable to all derailment conditions. In the Volpe research, a simple two-dimensional model of a train with an artificially triggered motion and induced motions of a derailment was used. Volpe could have used other initial conditions that replicate derailment triggers, which would have shown car-to-car impacts at greater than 50 percent of the train speed. More important, this accident modeling approach did not take into consideration many of the three-dimensional, highly nonlinear dynamic responses that occur in derailments. Consequently, the Board believes that while establishing tank car puncture resistance at 25 mph is an improvement that will enhance tank car safety, it does not represent a standard for ensuring safety in 50-mph derailments. The Safety Board believes that more technically rigorous models should be developed and validated. In Safety Recommendations R-04-6 and -7, the Safety Board urged the FRA to validate a predictive model for quantifying the relevant dynamic forces acting on railroad tank cars during an accident and to initiate rulemaking to develop and implement appropriate design standards for pressurized tank cars. Safety Board staff evaluated the tank car failures in the Minot accident by utilizing the dynamic fracture toughness data for TC-128B steel developed through FRA-funded research conducted at the Southwest Research Institute. Based on the data, Safety Board staff determined that these tank cars failed from structural loads caused by high-speed impacts with frozen ground. No sign of a puncture in the tank car walls (that is, by impacting objects such as couplers) was found in the tank cars. Many previous tank car failures have been caused by impacts not only with couplers and drawbars, but also with other objects of varying size and shape, such as side-to-side and localized impacts with other freight cars, the ground, rails, and wheel sets. Tank car failures have also occurred following severe crushing damage and/or denting. In the preamble of the NPRM, PHMSA states the following: [The U.S. Department of Transportation’s] tank car research has shown that the rupture of tank cars and loss of lading are principally associated with the car-to-car impacts that occur as a result of derailments and train-to-train collisions. The Safety Board does not disagree with this statement but is concerned that the proposed rule defines only a puncture-resistance standard for tank cars. Although this is an important aspect of tank car safety enhancement, the proposed standard falls short of meeting the goal of ensuring that tank cars can withstand the spectrum of loads from a variety of impacts that are known to have occurred during past derailments. The Board intentionally worded Safety Recommendation R-04-06 to include the different types of critical-loading conditions observed in derailments. Again, the Safety Board believes that additional modeling and testing of various loading scenarios is needed to address this concern. The proposed rule also states that because the data from FRA-funded research show that measured values of fracture toughness for tank car steels vary by a factor of four, criteria based on fracture toughness cannot be developed for tank car steels. However, the Safety Board has an alternate interpretation and notes that the variation in fracture toughness values occurred over a wide temperature range (from about -50° F to about 72° F). The FRA research values do demonstrate that at any given temperature, the variation of fracture toughness is generally bounded by a factor of two or less. Such a variation is common to this class of steels and has been used in other applications to define fracture-based criteria. Additionally, as shown in the evaluation by Safety Board staff, through use of a statistically valid estimate of the lower bound for measured fracture toughness, one can show reliable estimates of crack sizes necessary to generate ruptures from impact-generated cracks. Fracture toughness determines the critical size of an impact-generated crack that can be sustained in a given tank car design without a structural failure under specified operating conditions. Fracture toughness also determines whether a tank car that sustains localized structural failures from impact loads can resist catastrophic rupture. Therefore, the Safety Board believes that requirements for fracture toughness also should be part of the design specifications. In evaluating the safety of new tank car designs, a standard for required fracture toughness of construction materials should be included as recommended in Safety Recommendation R-04-7. The Safety Board also is concerned that the proposed standards would allow new designs to be approved based solely on computational analysis. As part of the Next Generation Rail Tank Car Project (NGRTCP), Dow Chemical Company has funded three tank car impact tests at Transportation Technology Center, Inc. Although the initial computational simulations of these tests have shown a good correlation with the overall test results, a reliable capability to accurately predict material failure and resultant puncture of the tank walls solely from computational simulations has not been demonstrated. Therefore, we believe that computational simulations, until demonstrated to reliably predict material and structural failures, must be complemented by a well-designed and comprehensive testing program to qualify tank car designs. The Safety Board reviewed the proposed qualification tests for simulating punctures in Appendix C. The three tests already conducted in the NGRTCP have demonstrated that tank car body motion under impact conditions can have a significant influence on the degree of damage done to a tank car. To ensure that the test protocols described in Appendix C of the NPRM accurately simulate puncture resistance, the rigid body motion should be constrained. Operational Restrictions The Safety Board supports, in principle, the implementation of the proposed speed restrictions for trains with tank cars transporting PIH gases, as addressed in Safety Recommendation R-05-16. The Board also notes that, in response to Safety Recommendation R-05-15, the NPRM further proposes additional speed restrictions through non-signal territory for trains with tank cars that transport PIH gases and that do not meet the enhanced performance standards. However, the Board does not believe that the operating restrictions being proposed in the NPRM fully address Safety Recommendations R-05-15 and -16. In the NPRM, the proposed interim standard would reduce the speed of trains transporting PIH materials in tank cars that do not meet the proposed performance standards for structural integrity. These trains could not exceed 30 mph in non-signal territory. PHMSA states that this speed restriction is in response to Safety Recommendations R-05-15 and -16, which were issued as a result of the Graniteville investigation. The Safety Board notes that Safety Recommendation R-05-15 applies to any train operating in non-signal territory and in the absence of switch position indicator lights or other automated systems that provide train crews with advance notice of switch positions. Because the NPRM does not address speed restrictions for any train operating in territory without switch indicator lights or automated systems to provide switch positions, the NPRM does not fully address Safety Recommendation R-05-15. Similarly, the NPRM does not fully address Safety Recommendation R-05-16 because the NPRM does not include operating measures to minimize impact forces from accidents and reduce the vulnerability of tank cars transporting PIH materials, as stated in the recommendation. Positioning of tank cars toward the rear of trains and reducing speeds through populated areas were specifically suggested in the recommendation text as examples of the operational measures that should be considered. Further, the NPRM states that the Safety Board classified Safety Recommendations R-05-15 and -16 as “Open—Response Received” but fails to mention that the Safety Board classified the two recommendations respectively as “Closed—Unacceptable Action” and “Open—Unacceptable Response” on June 7, 2007. In its June 7 letter regarding Safety Recommendation R-05-15, the Safety Board noted the FRA’s response, which stated that the recommendation was not feasible for operational and economic reasons and that the FRA had given its final response. The Safety Board also stated its concern that the FRA had neither fully acknowledged that there was a problem that needed to be addressed nor offered an alternate course of action. Regarding Safety Recommendation R-05-16, the Safety Board acknowledged the FRA’s concern that train-handling measures must be taken into consideration when positioning tank cars in freight trains. The Board also expressed its disappointment that the FRA neither pursued the placement of tank cars in trains and speed restrictions nor suggested other positive alternatives. Implementation Schedule The Safety Board supports the proposed implementation schedule for the design, construction, and deployment of a new enhanced tank car that meets the proposed performance standards. The planned schedule is very aggressive: design approval and commencement of construction of the higher performance tank cars within 2 years of the adoption of the final rule, replacement of 50 percent of the PIH fleet within 5 years, and replacement of 100 percent of the fleet within 8 years. The FRA has indicated that the proposed implementation schedule will also accelerate the retirement of pre-1989 pressure tank cars and the transfer of post-1989 pressure tank cars currently in PIH service to transporting less dangerous materials. The Board commends the FRA and PHMSA for the proposal to accelerate this transition. In closing, the Safety Board supports the stated goals of the NPRM but believes that it can be improved and strengthened as noted in this letter. The Safety Board appreciates the opportunity to comment on the notice.
Response: With respect to Safety Recommendations R-04-4 through -7, the FRA’s October 24, 2006, letter references its August 9, 2004, response. The Safety Board would like to point out that the contents of that earlier correspondence, as well as the discussions that occurred at meetings with the FRA, were analyzed in detail in the Board’s report of the Macdona accident (see pages 47-52), in which R-04-5 and -6 remained classified "Open--Acceptable Response," and R-04-4 and -7 were reclassified from "Open--Unacceptable Response" to OPEN -- ACCEPTABLE RESPONSE. No additional information has been submitted to alter those classifications. However, the Board suggests that the FRA review the Safety Board’s technical assessment of the significance of fracture toughness on tank car safety in accidents; this assessment was provided previously. This technical assessment has also been added to the docket for the Minot, North Dakota, accident.
Response: Letter Mail Controlled 10/31/2006 2:19:08 PM MC# 2060536: - From Joseph H. Boardman, Administrator: The FRA offers the following response to the reiteration of these four recommendations: FRA respectfully requests that the NTSB reference the FRA’s written response to the NTSB dated August 9,2004 (Enclosure 1). Furthermore, because of the long-term nature for completing the aforementioned recommendations, FRA respectfully requests that NTSB consider retaining the classifications for Safety Recommendations R-04-05 and R-04-06 as "Open-Acceptable Response" and reconsider classifying Recommendations R-04-04 and R-04-07 as "Open-Acceptable Response."
Response: The Safety Board addressed this recommendation in its 7/6/2006 Board Meeting on the 6/28/2004 accident in Macdona, Texas, noting that The FRA stated in its initial response to Safety Recommendation R-04-7 that further research was required, which may necessitate a 3-year effort to develop adequate tank car design-specific fracture toughness standards. In its June 22, 2005, response, the Safety Board stated that tank car design-specific fracture standards, such as Charpy impact values, can be achieved for standard manufacturing processes without waiting for the results of the modeling effort associated with Safety Recommendation R-04-6. The Board added that evaluation and analysis of the dynamics of the Minot accident can provide data about the levels of fracture toughness that may be necessary for pressure tank cars and that data from subsequent accidents in Macdona, Texas, and Graniteville, South Carolina, will provide additional information. Based on the FRA's response, Safety Recommendation R-04-7 was classified "Open - Unacceptable Response." On June 24, 2005, the AAR, in collaboration with the FRA, revised its Manual of Standards and Recommended Practices--Specifications for Tank Cars. Under this revision, the steel plate used in the construction of pressure tank cars ordered after July 1, 2005, must meet Charpy impact testing standards for the orientation transverse to the rolling direction of the steel plate, the orientation that has the weakest impact resistance. The Charpy test coupons must simulate the in-service condition of the material and must meet the minimum requirement of a 15 foot-pound average for three specimens, with no single value below 10 foot-pounds and no two below 15 foot-pounds at .30° F. The AAR's new standards ensure that a minimum level of impact resistance for normalized steel can be verified by a standardized testing method. The new standards also require that the Charpy tests be performed in the orientation of the sample material with the lowest impact property. With the implementation of these new standards, the emphasis is placed, properly, on fracture toughness properties rather than solely on normalization of the steel plate. The Safety Board considers the implementation of the AAR standards to be a first step in a process of developing a fracture toughness standard for steel in pressure tank cars. As demonstrated by the accidents in Graniteville, South Carolina, and in Macdona, punctures in chlorine tank cars with the release of the chlorine gas can be catastrophic, even if the operating stresses on the tank are too low to cause the catastrophic growth of the cracks generated by the penetration process. Consequently, the Safety Board considers a design-specific fracture toughness standard as specified in Safety Recommendation R-04-7 to include, in addition to a consideration of the lethality of the tank car contents, a structural level penetration and crack growth assessment. The Board believes that the data being developed at Southwest, particularly on the variability of the fracture toughness of the test samples, can also be used to advance Safety Recommendations R-04-6 and -7. The Board encourages the FRA to address these points in the modeling work underway at the Volpe National Transportation Systems Center and the University of Illinois at Chicago. Because it appears that the FRA is making progress on the modeling of accident forces and the development of fracture toughness standards, Safety Recommendation R-04-6 remains classified "Open--Acceptable Response," and Safety Recommendation R-04-7 is reclassified OPEN -- ACCEPTABLE RESPONSE. Because the Safety Board is convinced that the successful and timely completion of all four of the above safety recommendations is of critical importance to improving the safety of pressure tank cars and the protection of the public, the Safety Board reiterates Safety Recommendations R-04-4 through -7 to the FRA.
Response: In its 4/14/2006 report to Congress, "National Transportation Safety Board (NTSB) and DOT Office of Inspector General (OIG): Open Safety Recommendations on Pipeline and Hazardous Materials Safety," the DOT wrote:FRA does not have data readily available related to samples such as Charpy specimens. FRA is researching this area.
Response: Letter Mail Controlled 1/3/2006 11:09:17 AM MC# 2060001: - From Joseph H. Boardman, Administrator: It is FRA’s position that the objective of this recommendation can only be addressed when in-train forces can be better predicted through the culmination of modeling efforts related to Safety Recommendation R-04-6. The NTSB contends that FRA’s position is not reasonable. In response, FRA submits that since 1989, the shells of pressure tank cars have been required to be constructed of normalized steel. Based on the historic development of the standards for the steel in these tank cars, it is clear that this change was instituted in order to provide greater fracture toughness to the shell material. However, as pointed out in the NTSB’s report on the Minot accident, "a normalizing heat treatment does not guarantee a minimum material impact resistance. In order to ensure adequate impact resistance, other factors, such as the chemical composition and grain structure of the metal and the type of rolling process used in the manufacture of the steel, must also be controlled." Thus, specifying a normalizing heat treatment is only an indirect method of controlling impact resistance. It is FRA’s position that analysis and evaluation of the dynamics of the Minot, North Dakota; Macdona, Texas; Graniteville, South Carolina, and future accidents will give indications of what fracture toughness thresholds are necessary for pressure tank cars to survive train derailments. These evaluations may also be used in the validation of the predictive model of forces acting on tank cars under accident conditions. Nevertheless, in Safety Recommendation R-04-7, the NTSB proposes that FRA directly control impact resistance using a quantitative measure such as Charpy impact values. The NTSB submits this can be done at a level that can currently be achieved using standard manufacturing processes and without waiting for the results of the modeling efforts associated with Safety Recommendation R-04-6, and that such direct control will thus reduce the possibility that normalized steel with inferior impact resistance can enter into service. Additionally, the NTSB stated that evaluation and analysis of the dynamics of the Minot accident can provide some data about the levels of fracture toughness necessary for pressure tank cars, and that data from subsequent accidents, e.g., Macdona and Graniteville, will provide additional information. Ultimately, the NTSB urged FRA to reconsider its response to this recommendation. Safety Recommendation R-04-7 is classified "Open-Unacceptable Response." The FRA now desires to inform the NTSB that the AAR Tank Car Committee, in liaison with FRA, has recently issued an amendment to the Charpy testing requirements for tank car steels. The relevant text appears below: 2.2.1.1 Effective for cars ordered after July 1, 2005, each plate-as-rolled of ASTM A516, A302, A537, and AAR TC128 steel used for pressure tank car heads and shells must be Charpy impact tested transverse to the rolling direction in accordance with ASTM A20. The test coupons must simulate the in-service condition of the material and must meet the minimum requirement of 15 ft-lb average for three specimens, with no single value below I O ft-lb and no two below 15 ft-lb at -30° Fahrenheit. Plates for lowtemperature service described in 49 CFR 179.102 that require longitudinal impact testing at -50° Fahrenheit do not require transverse testing at -30° Fahrenheit. The FRA believes that this new requirement will go far in creating safer tank cars. Until such time as FRA is able to fully address this safety recommendation, we request that the NTSB classify Safety Recommendation R-04-7 as "Open-Acceptable Response."
Response: The Safety Board notes the FRA's position that the objective of this recommendation can only be addressed when in-train forces can be better predicted through the culmination of modeling efforts related to Safety Recommendation R-04-6. The Board does not believe that this position is reasonable. Since 1989, the shells of pressure tank cars have been required to be constructed of normalized steel. Based on the historic development of the standards for the steel in these tank cars, it is clear that this change was instituted in order to provide greater fracture toughness to the shell material. However, as pointed out in the Board's report on the Minot accident, "a normalizing heat treatment does not guarantee a minimum material impact resistance. In order to ensure adequate impact resistance, other factors, such as the chemical composition and grain structure of the metal and the type of rolling process used in the manufacture of the steel, must also be controlled." Thus, specifying a normalizing heat treatment is only an indirect method of controlling impact resistance. Safety Recommendation R-04-7 asked the FRA to directly control impact resistance using a quantitative measure such as Charpy impact values, and the Board believes that this can be done at a level that can currently be achieved using standard manufacturing processes and without waiting for the results of the modeling efforts associated with Safety Recommendation R-04-6. Such a direct control will reduce the possibility that normalized steel with inferior impact resistance can enter into service. Furthermore, the Safety Board believes that evaluation and analysis of the dynamics of the Minot accident can provide some data about the levels of fracture toughness that may be necessary for pressure tank cars and that data from subsequent accidents in Macdona, Texas, and Graniteville, South Carolina, will provide additional information. Analysis and evaluation of the dynamics of these and future accidents will give indications of the fracture toughness thresholds for pressure tank cars to survive train derailments, and can also be used in the validation of the predictive model of forces acting on tank cars under accident conditions. The Board urges the FRA to reconsider its response to this recommendation, and pending further response from the FRA on this subject, Safety Recommendation R-04-7 is classified OPEN -- UNACCEPTABLE RESPONSE.
Response: In its 2/28/2005 report to Congress, "Open Statutory Mandates Regarding Pipeline and Hazardous Materials Safety," the DOT wrote: FRA does not have data readily available related to samples such as Charpy specimens. Further research in this area is required.
Response: Letter Mail Controlled 8/18/2004 11:05:14 AM MC# 2040515: - From Betty Monro, Acting Administrator: This can only be addressed when in-train forces can be better predicted through the culmination of the modeling efforts referenced above. The behavior of large-scale structures, such as tank cars, are not readily related to samples such a Charpy specimens. This undertaking is now anticipated to be about a three-year effort. The Charpy tests, while good, may not be the best or most appropriate indicator of tank car ductile performance under various temperature and derailment conditions. Further research in this area is required. Because of the long-term nature for completing the above mentioned programs, we respectfully request that the NTSB classify Safety Recommendation R-04-7 as "Open-Acceptable Response."