The load car or cars must be on level track when measured.
Check cross level of track at each truck of load car or cars.
If track is out of level at any truck, it will be necessary to arrange to either have the track made level or have the shipment moved to a level track. All vertical measurements must be perpendicular to the plane of the tops of level rails. All horizontal measurements must be parallel to the plane of the tops of level rails, and taken from the longitudinal centerline of car. The heights H and the widths W must be given for both overhanging ends and also between the truck centers or bolster centers where the load is the maximum size. If idler car is used, Rule 8B of the AAR Open Top Loading Rules must be observed in order to maintain a 4 inch clearance below overhanging portion of load and above any part of idler car which load may contact.