CFR > Title 49 - Transportation > SUBTITLE B—Other Regulations Relating to Transportation > CHAPTER II—FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (Parts 200–269) > PART 230—STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS > SUBPART C—Steam Locomotives and Tenders (§230.66 to §230.116) > 230.112—Wheels and tires.

230.112—Wheels and tires.

(a) Mounting. Wheels shall be securely mounted on axles. Prick punching or shimming the wheel fit will not be permitted. The diameter of wheels on the same axle shall not vary more than 3/32 inch.
(b) Gage. Wheels used on standard gage track will be out of gage if the inside gage of flanges, measured on base line is less than 53 inches or more than 53 3/8 inches. Wheels used on less than standard gage track will be out of gage if the inside gage of flanges, measured on base line, is less than the relevant track gage less 3 1/2 inches or more than the relevant track gage less 3 1/8 inches.
(c) Flange distance variance. The distance back to back of flanges of wheels mounted on the same axle shall not vary more than 1/4 inch.
(d) Tire thickness. Wheels may not have tires with a minimum thickness less than that indicated in the table in this paragraph (d). When retaining rings are used, measurements of tires to be taken from the outside circumference of the ring, and the minimum thickness of tires may be as much below the limits specified earlier in this paragraph (d) as the tires extend between the retaining rings, provided it does not reduce the thickness of the tire to less than 1 1/8 inches from the throat of flange to the counterbore for the retaining rings. The required minimum thickness for tires, by wheel center diameter and weight per axle, is as follows:
Weight per axle (weight on drivers divided by number of pairs of driving wheels) Diameter of wheel center (inches) Minimum thickness (inches)
30,000 pounds and under 44 and under 11/4
Over 44 to 50 15/16
Over 50 to 56 13/8
Over 56 to 62 17/16
Over 62 to 68 11/2
Over 68 to 74 19/16
Over 74 15/8
Over 30,000 to 35,000 pounds 44 and under 15/16
Over 44 to 50 13/8
Over 50 to 56 17/16
Over 56 to 62 11/2
Over 62 to 68 19/16
Over 68 to 74 15/8
Over 74 111/16
Over 35,000 to 40,000 pounds 44 and under 13/8
Over 44 to 50 17/16
Over 50 to 56 11/2
Over 56 to 62 19/16
Over 62 to 68 15/8
Over 68 to 74 111/16
Over 74 13/4
Over 40,000 to 45,000 pounds 44 and under 17/16
Over 44 to 50 11/2
Over 50 to 56 19/16
Over 56 to 62 15/8
Over 62 to 68 111/16
Over 68 to 74 13/4
Over 74 113/16
Over 45,000 to 50,000 pounds 44 and under 11/2
Code of Federal Regulations 514
Over 44 to 50 19/16
Over 50 to 56 15/8
Over 56 to 62 111/16
Over 62 to 68 13/4
Over 68 to 74 113/16
Over 74 17/8
Over 50,000 to 55,000 pounds 44 and under 19/16
Over 44 to 50 15/8
Over 50 to 56 111/16
Over 56 to 62 13/4
Over 62 to 68 113/16
Over 68 to 74 17/8
Over 74 115/16
Over 55,000 pounds 44 and under 15/8
Over 44 to 50 111/16
Over 50 to 56 13/4
Over 56 to 62 113/16
Over 62 to 68 17/8
Over 68 to 74 115/16
Over 74 2
(e) Tire width. Flanged tires shall be no less than 5 1/2 inches wide for standard gage and no less than 5 inches wide for narrow gage. Plain tires shall be no less than 6 inches wide for standard gage and no less than 5 1/2 inches wide for narrow gage.