Expanding Certain Locomotive Wheel Set Diameter Variations

Document Headings Document headings vary by document type but may contain the following: the agency or agencies that issued and signed a document the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to the agency docket number / agency internal file number the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Department of Transportation Federal Railroad Administration 49 CFR Part 229 [Docket No. FRA-2025-0126] RIN 2130-AD50 ( printed page 55776) AGENCY: Federal Railroad Administration (FRA), Department of Transportation (DOT). ACTION: Final rule. SUMMARY: This rule amends FRA's locomotive safety regulations to expand the maximum permitted variation in diameter for locomotive wheel sets using alternating current technology, in response to a Class I railroad's May 2019 petition for rulemaking and innovations in traction motor control. DATES: This rule is effective September 30, 2026. FOR FURTHER INFORMATION CONTACT: Gary Fairbanks, Staff Director, Motive Power & Equipment Division, FRA, telephone: (202) 230-9594, email: gary.fairbanks@dot.gov ; or Michael Masci, Attorney Adviser, FRA, telephone: (202) 302-7177, email: michael.masci@dot.gov . SUPPLEMENTARY INFORMATION: I. Background Consistent with Executive Order (E.O.) 14192, Unleashing Prosperity Through Deregulation ( 90 FR 9065 , Feb. 6, 2025), and E.O. 14219 , Ensuring Lawful Governance and Implementing the President's “Department of Government Efficiency” Deregulatory Initiative ( 90 FR 10583 , Feb. 25, 2025), FRA is reviewing its regulatory requirements in 49 CFR parts 200 through 299 and repealing requirements that are outdated and redundant. On July 1, 2025, FRA published a notice of proposed rulemaking (NPRM) that proposed to amend 49 CFR 229.73(b) to expand the maximum permitted variation in diameter for …