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| Re: Sunday night on Twitter @wmata (1588039) | |||
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Re: Sunday night on Twitter @wmata |
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Posted by Sand Box John on Tue Oct 19 09:58:35 2021, in response to Sunday night on Twitter @wmata, posted by Joe on Sun Oct 17 20:59:27 2021. Here is the deal with the 7k cars.Multiple cars are have had issues with the wheels on the wheel sets slipping out of gauge (wider then correct gauge). The derailment on 10 12 2021 was caused by one of the flanges on the out of gauge wheel sets picking the point of the frog in junction turnout south of the Rosslyn Station. NTSB WMATA Metrorail Derailment Media Briefing starting at 22:07 This is sounding like an issue with the assembly of the wheel sets. Seems like the vendor that made the wheel sets for Kawasaki were fitting wheels to the axles that had interference fits that were out of tolerance. Either the inside diameter of the wheel bore was to big or the outside diameter of the axle was to small or combination of both. It could also be that the interference fit tolerances used were not correct in the first place. The tolerance used in interference fits are measured in ten thousands of an inch or one hundreds of mileometer. The temperature of two parts being interference fitted must be same when the measurements are made. John in the sand box of Maryland's eastern shore. |
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