1.1This specification covers carbon steel girder rails² of three classes based on type or type and weight, and chemistry defined as follows and in Table 1.

TABLE 1 Chemical Requirements, %

	Class A	Class B	Class C
Carbon	0.60-0.75	0.70-0.85	0.75-0.90
Manganese	0.60-0.90	0.60-0.90	0.60-0.90
Phosphorus, max	0.04	0.04	0.04
Silicon	0.10-0.40	0.10-0.40	0.10-0.40

1.1.1Unless otherwise specified by the purchaser, girder-guard rails shall be Class A.

1.1.2Plain and grooved-girder rails under 135 lb/yd (67.1 kg/m) in weight shall be specified by the purchaser as either Class A or Class B.

1.1.3Plain and grooved-girder rails of 135 lb/yd in weight and heavier shall be Class C, unless otherwise specified.

1.2The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.