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| Re: More info on BOMBardier R-179 welding crack prototype cars issue (1305500) | |||
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Re: More info on BOMBardier R-179 welding crack prototype cars issue |
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Posted by Jace on Fri Aug 1 21:00:19 2014, in response to Re: More info on BOMBardier R-179 welding crack prototype cars issue, posted by Joe V on Thu Jul 31 17:54:00 2014. Lots of big mistakes on the Rockwells. The R46 trucks were an extension of an inside frame design already in use (I don't remember which cars, maybe BART). Rockwell didn't beef up the structure enough when going to an outside frame design, didn't do any long term service testing on the TA's rough track prior to the R46s and then had lots of issues with voids in the castings. Then there were problems with the primary springs being too soft, causing the trip cock out to move out of tolerance (the primaries were rubber collars around the bearings). They switched to a stiffer spring to keep the trip cock from moving but that started putting a lot more shock into the trucks. They probably would have had to replace the trucks anyway, the stiffer springs only accelerated the process.You can see why the R110 program came about after the R44 and R46 disasters. No more unproven technology, heavy duty trucks that went through extensive testing, lots of quality control and design review on new car projects. Catching microcracks on the R179s is not good news but it's much better to do this now then after the fleet is in service. This shows the process in place is working as intended. |
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