{"data":{"id":"us/49-cfr-229.73","jurisdiction":"us","citation":"49 CFR 229.73","heading":"Wheel sets.","body":"(a) The variation in the circumference of wheels on the same axle may not exceed 1/4 inch (two tape sizes) when applied or turned.\n(b) The maximum variation in the diameter between any two wheel sets in a three-powered-axle truck may not exceed 3/4 inch, except that when shims are used at the journal box springs to compensate for wheel diameter variation, the maximum variation may not exceed 1 1/4 inch. The maximum variation in the diameter between any two wheel sets on different trucks on a locomotive that has three-powered-axle trucks may not exceed 1 1/4 inch. The diameter of a wheel set is the average diameter of the two wheels on an axle.\n(c) On standard gauge locomotives, the distance between the inside gauge of the flanges on non-wide flange wheels may not be less than 53 inches or more than 53 1/2 inches. The distance between the inside gauge of the flanges on wide flange wheels may not be less than 53 inches or more than 53 1/4 inches.\n(d) The distance back to back of flanges of wheels mounted on the same axle shall not vary more than 1/4 inch.","path":["Title 49—Transportation","Subtitle B—Other Regulations Relating to Transportation","CHAPTER II—FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","PART 229—RAILROAD LOCOMOTIVE SAFETY STANDARDS","Subpart C—Safety Requirements"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-49.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:34Z","sha256":"bc8f83f8f837c1dbd3871c0391a4372255378b0b676a919fee014e205ba7d457","source_id":"us-cfr","stale":true,"prev":"us/49-cfr-229.71","next":"us/49-cfr-229.75"},"notice":"GroundRules: Original legal text. Not legal advice."}