General Order 64
Section VII
Detail Construction Requirements – Tower Lines
77
Crossings.
Where
tower lines cross over important railroads (see 17 (t)) or important signal
lines (see 17 (d)) or other tower lines of voltage exceeding 30,000 volts, the
towers supporting the crossing spans shall be designed to withstand with the
factors of safety of Section V the most severe conditions of temperature and
loading therein specified, combined with the unbalanced pull which would be
caused by any two broken or dead ended conductors in the span adjacent to the
crossing.