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ODOT asks for oil train moratorium



PORTLAND (AP) — Oregon transportation officials are asking federal rail authorities to suspend crude oil trains in the Pacific Northwest’s Columbia River Gorge until there is a better understanding of what caused a fiery derailment there this month.

State Department of Transportation officials presented their concerns Thursday at a meeting in Hood River and made public a letter to the Federal Rail Administration (FRA) asking for the moratorium on oil-only trains in Oregon. The letter expresses concern about lag bolts, a type of fastener used on a curved section of track to attach the rail to the rail tie.

Union Pacific has said a failure of the bolts caused the June 3 derailment.

More than 12 of the 96 oil cars derailed, sparking a fire and forcing evacuations. No one was injured.

Here is the text of the letter from Hal Gard, administrator of the ODOT Rail and Public Transit division, to Mark Daniels. Region Administrator, FRA:

“While it is clear the investigation into this incident is ongoing, preliminary indications point to broken Rectangular Head Timber Coach screws. There were a number of broken screws found at the accident site, many of which exhibited evidence of having been broken for a significant amount of time prior to the derailment.

“Given the nature of this defect, it is not detectable by normal inspection methods, either physical … or by recent GRMS (Gauge Restraint Measurement System) tests conducted by the Union Pacific Railroad by hyrail.

“It is unclear if the broken Rectangular Head Timber Coach screws are the result of defective metal or manufacturing, over torqueing during installation or the fastening system, is insufficient for these types of loads in this vicinity. New real was installed at this location in 2013 so these fasteners are relative new.

“Until the underlying cause of the bolt failure is understood and a means of detecting this defect is developed, we request a moratorium on running unit oil trains over sections of track that contain track fasteners of this material within the state of Oregon.”



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Zinzendorf 1 year, 8 months ago

While it was not a cold day at the time of accident, the gorge could over the previous winters sustained freezing temperature. This in general could degrade the ductility performance of high strength material as in this case of the lag bolt. If the lag bolt sustained bending, tension as well as shear to resist the lateral sideswipe force of the wheel as fatigue load, it can fail in couple of years (or say 100,000 cycles). On the matter of bending, the bolt can sustain bending stress if the bolt hole was enlarged by repeated lateral force cycles at the top of the rail. So the high strength specification may actually be a detriment for repeat forces of dynamic nature, fatigue demand in annual cold temperature environment. It is not clear if further studies were made on the failure mechanism other than the knowledge the lag bolt has failed. What is required should be a proper studies of both the broken tie plates and broken lag bolts by an academic metallurgist as well as finite element simulations to ensure the proper construction and maintenance of the rail on the curves.

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