This specification deals with the standard requirements for heat-treated alloy steel axles and solid design roller bearing axles with machined bodies for mass transit and commuter cars in electric and locomotive hauled railway service. Various axle designs are used for this service including motor and non-motor with either inboard or outboard journals. Materials shall be forged, cooled and heat treated by normalizing, liquid quenching, tempering, and straightening. Steels shall conform to chemical composition requirements specified for each of the seven classes considered here. Conformance to mechanical property requirements such as tensile strength, yield strength, elongation, and reduction of area, shall be evaluated by tensile tests. Details of nondestructive ultrasonic and magnetic particle examination procedures are discussed thoroughly. Final axle products shall conform to purchaser-specified size, shape, and finish. Rough machining shall be free of excessively rough ridges and coarse chatter marks, and the finish machined axle surfaces shall be free of injurious imperfections.

1.1 This specification covers heat-treated alloy steel axles for mass transit and commuter cars in electric and locomotive hauled railway service.

1.2 This specification is for solid design roller bearing axles with machined bodies.

1.3 Various axle designs are used for this service including motor and non-motor with either inboard or outboard journals.

1.4 Supplementary requirements including those in the general requirements of Specification A 788/A 788M are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.

1.5 Unless the order specifies the applicable "M" specification designation, the axles shall be furnished to the inch-pound units.

1.6 The values stated in either inch-pound or SI (metric) units are to be regarded separately as standard. Within the text and tables, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.