(1) Each open top car containing lading of a height exceeding fifteen (15) feet six (6) inches above top of rail, or which extends laterally more than five (5) feet five (5) inches from the centerline of the car, the movement of which is hereby authorized, shall be marked, stenciled or placarded, and such markings maintained in a legible condition to read:
"THIS CAR "THIS CAR
EXCESS OR EXCESS
The words "EXCESS HEIGHT" or "EXCESS WIDTH" to occupy the greater portion of a space 7" x 10" enclosed within a 3/4" solid border. Letters and border to be of contrasting colors. All such required markings and placarding shall be placed on the side adjacent to the ladder or handholds near the floor line of the car at each of the four corners where practicable, and in addition one each of such signs shall be placed on each side of the load in a conspicuous position.
(2) The movement of open top cars containing lading which extends laterally in excess of five (5) feet five (5) inches is hereby authorized only if the lading is of such a nature that it cannot practically be reduced in dimensions.
(3) The movement of all open top cars having lading in excess of fifteen (15) feet six (6) inches in height, or which extends laterally in excess of five (5) feet five and one half (5½) inches from centerline of car will be authorized by written notice stating the total number of such cars, and advising that no member of the train crew is required to ride on top of such high car or the side of any such wide car.
(4) A written notice shall be delivered to every train containing any car, the lading of which extends laterally in excess of 5'5½" from the centerline of the car or in excess of 15'6" in height above top of rails, informing the crew of the train that the train includes such car or cars, stating the total number thereof and advising that no member of the train crew is required to ride on the side of any such wide car or top of any such high car.
(5) Yard Supervisors shall be given notification sufficiently in advance of the arrival of such wide loads as described in (3) as to enable them to take necessary precautions to safeguard employees in yard.
(6) Open top cars containing lading having an overall height in excess of fifteen (15) feet six (6) inches above top of rail, if otherwise in compliance with these requirements, and the nature of which precludes the possibility of employees passing over the cars, are exempt from the provisions of (3) , (4) , and (5) , but written notice must be given to all members of train crew informing them of the presence of such loads.
(7) Exemptions. The common carrier railroads are hereby authorized to move excess height loads and width loads, as described in (1) over roads or portions thereof, without complying with the provisions of (1) , provided that clearances equivalent to the minimum herein prescribed for cars having a height of fifteen (15) feet six (6) inches and width of ten (10) feet ten (10) inches are maintained.