Fire Fighter Safety No. 1 Questions taken from Jones & Bartlett Fundamentals of Fire Fighter Skills (3rd Edition) Progress Indicator: Question 4 of 15 4.  All trolley wires and feeder lines installed on underground haulage roads shall be placed as far to one side of the passageway as is practicable, but not less than __________ outside of line of rail, and securely supported upon hangers which shall not be more than __________ apart and efficiently insulated. Choices: twelve inches, 36 feet six inches, 24 feet six inches, 12 feet twelve inches, 12 feet