There exists a published photo of a Budd dome car being squeezed in a hydraulic press, to measure deflection in the carbody & appease skeptical RR CMO's. No doubt the RDC was also over - engineered; besides also being built with long lasting Stainless Steel. I have read a NTSB report of a Penn Central RDC that hit a flatbed truck & had a steel coil pinball through the car. Several passengers died; many more were injured. Although no railroad car ( or even locomotive ) can be expected to withstand such an impact, the NTSB report noted the carbody maintained its' integrity. The failure of the end door was noted in the report; the center interior bulkhead stopped the coil from going all the way through the car.