General Order 64-A

Section XI

Supply Lines And Communication Lines Crossings Over Railways

113.3    Limitation of Spans Lengths.

The crossings span shall be made as short as is practicable.  In no case shall the length of the crossing span be greater than the normal span of the line and the length of the next adjoining span shall be not greater than one and one-half times the normal span except where spans of extraordinary length are made necessary by extraordinary conditions of topography.