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Locomotive Cabs, and Crew Safety in Collisions

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[quote user="edblysard"] The collision posts are located in the nose right where the bend from the "flat" door panel begins to bend. They are about 8" wide at the base and taper to about 3" at the top, and are 3" thick. Welded to the frame. The front of the pilot and knuckle/coupler assembly is designed to lift and trap automobiles between the knuckle/drawbar and the front porch, preventing them from entering the cab. The collision post are designed to make any rail car or automobile that rides over the pilot and over the porch to deflect upward, it should either flip the car or object, or deflect it to the side. The post are strong enough to be used as lifting points for the locomotive if needed, I have seen one picked up by them. Both GE and EMD have these posts, on GEs they are stand-alone structures, you can see them when you step into the nose door, on EMDs they are part of the nose structure.   I agree with Paul, based only on the photos, that the rear car was picked up by the pilot, then deflected up and over the cab by the post/nose structure, but then was trapped on the roof by the bridge, which started the accordion effect, which placed a tremendous amount of mass and weight on the post and front of the cab, and when adding the kinetic energy of the moving locomotive and the entire mass it simply overcame the structure of the frame and then the cab. If you look at the photos, you can see two pieces of the nose panels still intact. The two panels which were to either side of the nose door have the collision post behind them, and they are welded to the frame precisely where the frame bent back and up. The post didn't fail; they did exactly what they were designed to do, by lifting the car up and over, preventing it from shearing the cab off at the walkway. Had it not been for the type of car the locomotive hit, and the bridge above the locomotive, I think, (opinion only) the crew would have survived. But again, this is my opinion. You're not looking at a safety design failure per say, but at an odd set of circumstances no one would have anticipated in the bridge being a factor in overall effect. <div style="clear:both;"></div> [/quote] Ed, Thanks for that information and perspective.  I would not necessarily conclude that the collision posts failed to do their job because I don’t know exactly what their job is intended to be.  It looks to me that the collision posts did not bend over their length but they bent the connection to the frame.  Whether that entailed the bending of the actual posts near their bottoms, or the bending of the frame, it seems to me that the posts failed to remain vertical and withstand the impact force.  If they bent the frame, the posts acted like levers that multiplied the bending force to their connection to the frame.  <o:p></o:p> I agree that it looks like the car rode up the pilot.  But when it hit the collision posts, it bent them back about 45 degrees and created a perfect ramp for the cars to continue riding upward.  When the cars reached the top of the ramp (at the top of the collision posts), they pushed straight back into the softer cab structure and peeled / rolled it back.  From that point, the cars rode all the way over the engine as they rolled the upper cab structure back.  <o:p></o:p> I would think that if one were to expect those posts to withstand the typical impact in a collision with railroad equipment, the posts would have to be gusseted to the frame way back maybe as far as 4-6 feet horizontally.  And even with that, the whole frame would have to be reinforced to prevent it from bending at that gusset endpoint 4-6 feet back.  <o:p></o:p> If the collision posts had been more resistant to being bent back, they might have conveyed enough impact force forward to buckle the couplings of the flat cars one or two joints ahead, and cause the cars to deflect sideways thus preventing the riding up the front of the locomotive     <o:p></o:p> I will grant that flat cars are unique in that they have the same frame strength as other cars, but no other associated superstructure to blunt the impact.  They are like javelins, and they concentrate all the force on a relatively small spot.  If I were to speculate (which I always do), I would say that the collision posts failed to do what they were intended to do.  I expect them to become the center of intense focus and controversy by everyone having an interest in their performance; particularly so because the speed was so low at the time of impact.
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