FRA has the enforcement authority and responsibility to ensure the safe transportation of hazardous materials. Movement approvals are required for certain types of hazardous material shipments, such as a one time shipment of hazardous material carrying tank cars for repair and other non-conforming packagings designed, marked or otherwise represented for the transportation of hazardous material. On January 31, 2012, FRA issued HMG-127 and implemented a 4-tier approval process for such movements. HMG-127 was revised on March 27, 2012, resulting in a 3-tier approval process. The most recent version of HM-127 was issued October 7, 2014 and should be followed when applying for a one-time movement approval in accordance with 49 CFR § 174.50.