For top side rail inward deformation, where should the measurement be taken from?

Taking the measurement for top side rail inward deformation from the undamaged area is crucial because it establishes a baseline for assessing the extent of the deformation. By referencing an undamaged section, it ensures that the measurement reflects the actual impact of any damage without being influenced by pre-existing conditions. This approach facilitates a clear and accurate evaluation of the structural integrity of the rail, helping to determine if the deformation exceeds acceptable limits.

In contrast, measuring from the exterior or interior recessed corrugations or the front panel could produce misleading results. These areas might not provide a true representation of the rail's original condition, as they may inherently possess variances due to design or pre-existing wear, thus compromising the reliability of the assessment.