1.1 This specification covers one-wear, two-wear, and multiple-wear cast carbon steel wheels for use on locomotives and cars, designated Class U, untreated, and Classes L, A, B, and C, heat-treated wheels.

1.2 The service for which the various classes are intended is as follows:

1.2.1 Class B or C wheels shall be used for freight cars in interchange service.

1.2.2 Class B or C wheels are recommended for use on locomotives.

1.2.3 For passenger car service, the various classes are intended generally as follows:

1.2.3.1 Class L -High speed with more severe braking conditions than other classes and light wheel loads.

1.2.3.2 Class A -High speed service with severe braking conditions, but moderate wheel loads.

1.2.3.3 Class B -High speed service with severe braking conditions and heavier wheel loads.

1.2.3.4 Class C -( ) Service with light braking conditions and heavier wheel loads.

1.2.3.5 Class C -( ) Service with heavier braking conditions where off-tread brakes are employed.

1.2.4 Class U -Wheels may be used in service in which the wheel load and braking are low.

1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.

1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.