185(1)No person shall operate or move any crawler-type tractor, steam shovel, derrick, roller, or any equipment or structure having a normal operating speed of twenty or less kilometres per hour or a vertical body or load clearance of less than four centimetres for each metre of the distance between any two adjacent axles or in any event of less than twenty centimetres measured above the level surface of a roadway, upon or across any tracks at a railroad grade crossing without first complying with this section.