General Order 95

Section VII

Detailed Construction Requirements for Trolley and Electric Railway
Contact and Feeder Conductors and Their Supporting Messengers,
Span Wires, Etc. (Class T Circuits)

77.3    Material and Strength

A.    Material

Span wires, backbones, messengers, etc., shall be stranded and of galvanized steel or other corrosion–resisting material of equal durability.

B.    Strength

The strength of span wires, backbones, messengers, etc., shall be such that the safety factors of Rule 44 are met.