1.1 This specification covers uncoated stress-relieved steel bars for use in prestressed concrete railroad ties.

1.2 Supplement I describes low-relaxation bars and relaxation testing for that product. Low-relaxation bars shall be furnished when specifically ordered, and may be furnished in place of regular bars if mutually agreed to by the purchaser and manufacturer.

1.3 This specification is applicable for orders in either inch-pounds units (as Specification A 911) or in SI units (as Specification A 911M).

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