Pub. L. 114–94, div. A, title VII, § 7311, Dec. 4, 2015, 129 Stat. 1601, provided that: “(a) Government Accountability Office Study.—“(1) In general.—The Comptroller General of the United States shall conduct an independent evaluation of ECP brake systems, pilot program data, and the Department [of Transportation]’s research and analysis on the costs, benefits, and effects of ECP brake systems. “(2) Study elements.—In completing the independent evaluation under paragraph (1), the Comptroller General shall examine the following issues related to ECP brake systems:“(A) Data and modeling results on safety benefits relative to conventional brakes and to other braking technologies or systems, such as distributed power and 2-way end-of-train devices. “(B) Data and modeling results on business benefits, including the effects of dynamic braking. “(C) Data on costs, including up-front capital costs and on-going maintenance costs. “(D) Analysis of potential operational benefits and challenges, including the effects of potential locomotive and car segregation, technical reliability issues, and network disruptions. “(E) Analysis of potential implementation challenges, including installation time, positive train control integration complexities, component availability issues, and tank car shop capabilities. “(F) Analysis of international experiences with the use of advanced braking technologies. “(3) Report.—Not later than 18 months after the date of enactment of this Act [Dec. 4, 2015], the Comptroller General shall transmit to the Committee on Transportation and Infrastructure of the House of Representatives and the Committee on Commerce, Science, and Transportation of the Senate a report on the results of the independent evaluation under paragraph (1). “(b) Emergency Braking Application Testing.—“(1) In general.—The Secretary [of Transportation] shall enter into an agreement with the National Academy of Sciences to—“(A) complete testing of ECP brake systems during emergency braking application, including more than 1 scenario involving the uncoupling of a train with 70 or more DOT–117 specification or DOT–117R specification tank cars; and “(B) transmit, not later than 18 months after the date of enactment of this Act, to the Committee on Transportation and Infrastructure of the House of Representatives and the Committee on Commerce, Science, and Transportation of the Senate a report on the results of the testing. “(2) Independent experts.—In completing the testing under paragraph (1)(A), the National Academy of Sciences may contract with 1 or more engineering or rail experts, as appropriate, that—“(A) are not railroad carriers, entities funded by such carriers, or entities directly impacted by the final rule issued on May 8, 2015, entitled “Enhanced Tank Car Standards and Operational Controls for High-Hazard Flammable Trains” (80 Fed. Reg. 26643); and “(B) have relevant experience in conducting railroad safety technology tests or similar crash tests. “(3) Testing framework.—In completing the testing under paragraph (1), the National Academy of Sciences and each contractor described in paragraph (2) shall ensure that the testing objectively, accurately, and reliably measures the performance of ECP brake systems relative to other braking technologies or systems, such as distributed power and 2-way end-of-train devices, including differences in—“(A) the number of cars derailed; “(B) the number of cars punctured; “(C) the measures of in-train forces; and “(D) the stopping distance. “(4) Funding.—The Secretary shall provide funding, as part of the agreement under paragraph (1), to the National Academy of Sciences for the testing required under this section—“(A) using sums made available to carry out sections 20108 and 5118 of title 49, United States Code; and “(B) to the extent funding under subparagraph (A) is insufficient or unavailable to fund the testing required under this section, using such sums as are necessary from the amounts appropriated to the Secretary, the Federal Railroad Administration, or the Pipeline and Hazardous Materials Safety Administration, or a combination thereof. “(5) Equipment.—“(A) Receipt.—The National Academy of Sciences and each contractor described in paragraph (2) may receive or use rolling stock, track, and other equipment or infrastructure from a railroad carrier or other private entity for the purposes of conducting the testing required under this section. “(B) Contracted use.—Notwithstanding paragraph (2)(A), to facilitate testing, the National Academy of Sciences and each contractor may contract with a railroad carrier or any other private entity for the use of such carrier or entity’s rolling stock, track, or other equipment and receive technical assistance on their use. “(c) Evidence-Based Approach.—“(1) Analysis.—The Secretary shall—“(A) not later than 90 days after the report date, fully incorporate the results of the evaluation under subsection (a) and the testing under subsection (b) and update the regulatory impact analysis of the final rule described in subsection (b)(2)(A) of the costs, benefits, and effects of the applicable ECP brake system requirements; “(B) as soon as practicable after completion of the updated analysis under subparagraph (A), solicit public comment in the Federal Register on the analysis for a period of not more than 30 days; and “(C) not later than 60 days after the end of the public comment period under subparagraph (B), post the final updated regulatory impact analysis on the Department of Transportation’s Internet Web site. “(2) Determination.—Not later than 2 years after the date of enactment of this Act, the Secretary shall—“(A) determine, based on whether the final regulatory impact analysis described in paragraph (1)(C) demonstrates that the benefits, including safety benefits, of the applicable ECP brake system requirements exceed the costs of such requirements, whether the applicable ECP brake system requirements are justified; “(B) if the applicable ECP brake system requirements are justified, publish in the Federal Register the determination and reasons for such determination; and “(C) if the Secretary does not publish the determination under subparagraph (B), repeal the applicable ECP brake system requirements. “(3) Savings clause.—Nothing in this section shall be construed to prohibit the Secretary from implementing the final rule described under subsection (b)(2)(A) prior to the determination required under subsection (c)(2) of this section, or require the Secretary to promulgate a new rule on the provisions of such final rule, other than on the applicable ECP brake system requirements, if the Secretary does not determine that the applicable ECP brake system requirements are justified pursuant to this subsection. “(d) Definitions.—In this section, the following definitions apply:“(1) Applicable ecp brake system requirements.—The term ‘applicable ECP brake system requirements’ means sections 174.310(a)(3)(ii), 174.310(a)(3)(iii), 174.310(a)(5)(v), 179.202–10, 179.202–12(g), and 179.202–13(i) of title 49, Code of Federal Regulations, and any other regulation in effect on the date of enactment of this Act requiring the installation of ECP brakes or operation in ECP brake mode. “(2) Class 3 flammable liquid.—The term ‘Class 3 flammable liquid’ has the meaning given the term flammable liquid in section 173.120(a) of title 49, Code of Federal Regulations. “(3) ECP.—The term ‘ECP’ means electronically controlled pneumatic when applied to a brake or brakes. “(4) ECP brake mode.—The term ‘ECP brake mode’ includes any operation of a rail car or an entire train using an ECP brake system. “(5) ECP brake system.—“(A) In general.—The term ‘ECP brake system’ means a train power braking system actuated by compressed air and controlled by electronic signals from the locomotive or an ECP–EOT to the cars in the consist for service and emergency applications in which the brake pipe is used to provide a constant supply of compressed air to the reservoirs on each car but does not convey braking signals to the car. “(B) Inclusions.—The term ‘ECP brake system’ includes dual mode and stand-alone ECP brake systems. “(6) Railroad carrier.—The term ‘railroad carrier’ has the meaning given the term in section 20102 of title 49, United States Code. “(7) Report date.—The term ‘report date’ means the date that the reports under subsections (a)(3) and (b)(1)(B) are required to be transmitted pursuant to those subsections.”