OvermodI don't know whether to laugh or cry that they pressed in a replacement pin with porta-power and then apparently tack-welded it to the drawbar eye.
Feature they figured that was adequate to get the trainset to the shop at restricted speeds. Temporary repairs.
Never too old to have a happy childhood!
BaltACD Overmod I don't know whether to laugh or cry that they pressed in a replacement pin with porta-power and then apparently tack-welded it to the drawbar eye. Feature they figured that was adequate to get the trainset to the shop at restricted speeds. Temporary repairs.
Overmod I don't know whether to laugh or cry that they pressed in a replacement pin with porta-power and then apparently tack-welded it to the drawbar eye.
It is surprising what can work in a pinch if you really need to move something.
I once made a swivel pin for a passenger car truck out of a piece of steel pipe and a large flat washer. Worked fine, and stayed in the car for quite some time. Not in revenue service of course, just for yard and shop moves.
Don't knock porta-powers, they are real life-savers in these situations.
Greetings from Alberta
-an Articulate Malcontent
Overmod Something tells me Vantuono received part of this report over the telephone, and I can even tell something about the regionality of the reporting person. "Haver de Grace"! The problem here is not so much a 'retaining bolt' as that the pin was pressed into the eye but subsequently moved far enough to strain the retaining bolt. I will wait for the paper in the FRA e-library that has the fatigue pattern for this bolt, but for the pin to be loose at all is the real shocking part of this failure. I don't know whether to laugh or cry that they pressed in a replacement pin with porta-power and then apparently tack-welded it to the drawbar eye.
Something tells me Vantuono received part of this report over the telephone, and I can even tell something about the regionality of the reporting person. "Haver de Grace"!
The problem here is not so much a 'retaining bolt' as that the pin was pressed into the eye but subsequently moved far enough to strain the retaining bolt. I will wait for the paper in the FRA e-library that has the fatigue pattern for this bolt, but for the pin to be loose at all is the real shocking part of this failure.
I don't know whether to laugh or cry that they pressed in a replacement pin with porta-power and then apparently tack-welded it to the drawbar eye.
Johnny
The stunning thing to me is that checking to see if the pin has lost it's press-fit and is loose in the drawbar wasn't part of some normal MI. Something like, every six months, remove the bolt and retaining disk and whack the pin with a hammer to see if it moves. Or even, every two year, remove drawbar and replace bushing and pin.
Not good, Amtrak....
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
OvermodThe problem here is not so much a 'retaining bolt' as that the pin was pressed into the eye but subsequently moved far enough to strain the retaining bolt.
The retaining plate was the only safety measure for the pin not the belt added to the suspenders. Even with close clearances a greased pin will work itself out of the connection under dynamic loads and permanent vibrations. A d=3'' pin with 10'' length weighs about 22 lbs.
I expect that the bolt holding the retaining plate failed from fatigue and both fell off leaving the pin unsecured. So a second bolt might prevented this as it is unlikely that both bolts fail simultanously if each bolt alone is able to hold the pin.
I think the weld would be between lug plate and pin and not eyebar. But even if otherwise the cpin can move in lug plate. The function is not restricted and as temporary solution good enough.Regard, Volker
VOLKER LANDWEHREven with close clearances a greased pin will work itself out of the connection under dynamic loads and permanent vibrations.
You know that, and I know that, but evidently Bombardier did not, and at least some parts of Amtrak maintenance staff did not. Unless the geometry of this 'bolt' and 'plate' are very different from what I'm expecting.
The statement that the missing hardware was recovered from the "truck frame" after a UDE from 123mph says the failure was very different from the pin just falling out. That is partly why I'll be waiting for the technical report on this with considerable interest.
Not sure the 'two is better than one' is a better answer, but until I see the arrangement I won't speculate. I'd have done final tension on a single critical bolt 'in line' with a pin like that either with hydraulic extension a la Doxford's or via Superbolting, not some torque-to-yield approximation on a pressed-fit component. But that is just my neurotic eye for detail. And I suspect this is a retainer screwed to the truck frame with only its periphery engaging the pin, not something concentric.
You may well be right about the lug plate; I saw 'pressed into the drawbar and then welded in place' as being two parts of one securement, and with a press fit at the drawbar I would presume all the 'fits' of the pin above and below would be lube-contaminated. Again the pictures in the upcoming report will be enlightening if we do not hear knowledgeable reports sooner...
My previous post was to emphasize my opinion that the retaining plate is the key to this accident.
We don't know if there perhaps once were two bolts and one got lost somehow before. Or there might have other measures.
You are right, we will have to wait for more details to understand the construction and the accident.Regards, Volker
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