30 CFR § 75.1003
Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires.
[STATUTORY PROVISIONS]
Trolley wires, trolley feeder wires, and bare signal wires shall be insulated
adequately where they pass through doors and stoppings, and where they cross
other power wires and cables. Trolley wires and trolley feeder wires shall be
guarded adequately:
(a) At all points where men are required to work or pass regularly
under the wires;
(b) On both sides of all doors and stoppings; and
(c) At man-trip stations.
The Secretary or his authorized representatives shall specify other
conditions where trolley wires and trolley feeder wires shall be adequately
protected to prevent contact by any person, or shall require the use of
improved methods to prevent such contact. Temporary guards shall be provided
where trackmen and other persons work in proximity to trolley wires and
trolley feeder wires.