Original Version

Rule 57.4-B2

57.4-B2)    Operated by Overhead Trolley:  The clearances specified in Table 1, Case 2, Columns A and D are based upon a maximum trolley pole throw of 26 feet.

Messengers, and Cables, which are bonded and grounded as specified in Rule 57.8, may have clearances above the rails or running surfaces used by trolley cars or coaches less than the distance specified in Table 1, Case 2, Columns A and D for trolley-throw clearance, provided the messengers and cables are not less than 4 feet above the trolley contact conductor and are encased in wood boxing or moulding 7/8-inch or more in thickness for distance of at least 2 feet horizontally from the vertical plane through each trolley contact conductor.

Strikeout and Underline Version

Rule 57.4-B2

57.4-B2)    Operated by Overhead Trolley:  The clearances specified in Table 1, Case 2, Columns A and D 26 feet and 27 feet respectively, are based upon a maximum trolley pole throw of 26 feet, the usual maximum height of a free trolley pole above the top of rails or surface of streets used by trolley cars or coaches.

EXECPTION:    Messengers, and Cables, which are bonded and grounded as specified in Rule 57.8, may have clearances above the rails or running surfaces of streets used by trolley cars or coaches less than the distance specified in Table 1, Case 2, Columns A and D for trolley-throw clearance, provided the messengers and cables are not less than 4 feet above the trolley contact conductor and are encased in wood boxing or moulding with a minimum 7/8-inch or more in thickness (or other suitable material having the same minimum electrical insulating qualities and mechanical strength) for distance of at least 2 feet horizontally from the vertical plane through each trolley contact conductor.

Final Version

Rule 57.4-B2

57.4-B2)    Operated by Overhead Trolley:  The clearances specified in Table 1, Case 2, Column A and D 26 feet and 27 feet respectively, are based upon a maximum trolley pole throw of 26 feet, the usual maximum height of a free trolley pole above the top of rails or surface of streets used by trolley cars or coaches.

EXECPTION:    Messengers, and Cables, which are bonded and grounded as specified in Rule 57.8, may have clearances above the rails or surfaces of streets used by trolley cars or coaches less than the distance specified in Table 1, Case 2, Column A and D for trolley-throw clearance, provided the messengers and cables are not less than 4 feet above the trolley contact conductor and are encased in wood boxing or moulding with a minimum 7/8-inch (or other suitable material having the same minimum electrical insulating qualities and mechanical strength) for distance of at least 2 feet horizontally from the vertical plane through each trolley contact conductor.