Great drawing, Larry. Where'd you get it from ?
"Never mind . . . " (after the late Gilda Radner as Emily Litella- see: http://en.wikipedia.org/wiki/Emily_Litella ). I thought to click on it and found out:
http://app.ntsb.gov/investigations/fulltext/RAB1203/RAB1203_6.jpg
The complete report: http://app.ntsb.gov/doclib/reports/2012/RAB1203.pdf
Wasn't a "picked switch"; instead: " . . . failure of the 18th rail car to properly negotiate a curve because of the inadequate side bearing clearance of the B-end truck assembly, likely due to a broken side bearing wedge plate attachment bolt, which caused a wheel to climb the rail, which derailed the car."
Thanks anyway !
- Paul North.
I think this is it, but not sure. youtube.com/watch?V=PFZiJP1uFEw Was a CSX in Ohio 29+ mins long.
Northtowne
we were taught very early to look at the points when a switch is thrown. a rock or piece of wood will cause a gap, you will notice that on a good switch though cause it will be hard to close. it could still happen though with good points
As for the flanges, the normal contour of the flange is rounded. A severely worn flange may actually have a sharp edge. Combine that with a switch point that's not tight against the stock rail (as already mentioned) and you may have a flange that tries, successfully, to sneak between the two.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Picking a switch means that the flange of a wheel manages to get between the movable "point" rail and the rail to which it should be tightly against try to take the route it shouldn't. Thus if the train is supposed to take a diverging route, if a point is worn or there is misalingment or some other cause, an axle might try to follow the "main" rather than the diverging route and cause a derailment. There are adjustments to the switch points that are made to keep this from happening and routine inspections to check these adjustments but as the expession goes "it happens". What is the URL for the youtube?
I was watching a youtube dreailment cleanup; it occured as one train was entering a siding for a pass and several cars (motive power had passed on by) derailed at or close therafter from the switch. One comment said the "cars may have picked the switch and the car wheel flanges may have been worn down" as a probable cause. What does this, if anything, mean?
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