PHMSA is considering amendments that would enhance safety and revise and clarify the Hazardous Materials Regulations (HMR) applicable to the transportation of hazardous materials by rail. In accordance with Executive Order 13563, Regulatory Review and Reinvention (Executive Order 13563; January 18, 2011), the Federal Rail Administration (FRA) has completed an internal review of the existing regulations set forth by PHMSA in 49 CFR part 174, which apply to persons who accept and transport hazardous materials by rail. Using the principals set forth in Executive Order 13563, FRA has reviewed the regulations in part 174 and other relevant sections of the HMR, and identified regulations that are outdated, unclear, no longer necessary, may present an undue economic burden on the regulated community, conflict with other North American standards and regulations, or do not sufficiently address technological advancements in the railroad operating environment. Further, FRA has identified several trends in industry practices and operating procedures that present new and different risks to safety that should be addressed in part 174 of the HMR. This rulemaking would more fully align the HMR with the results of the FRA review and would update, clarify, correct and provide relief of certain regulatory requirements applicable to the transportation of hazardous materials by rail.