Amtrak train breaks apart at 125 mph

[Anonymous]

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

[Overmod]

VOLKER LANDWEHR

Even 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...

[Anonymous]

Overmod

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.

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.

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.

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

[oltmannd]

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. 

 

 

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....

[Deggesty]

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. 

 

 

Apparently the transcriber had never heard of Havre de Grace?

[SD70Dude]

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.

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.

[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]

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. 

 

[Anonymous]

Thanks for the link.

One bolt holding the retaining disk? I once learned in steel construction studies that a single bolt is no bolt.
Regards, Volker

[BaltACD]

http://www.railwayage.com/index.php/passenger/high-performance/acela-pull-apart-preliminary-findings-fra.html

[zugmann]

Euclid

In the link and pin days, trains sometimes broke-separated in more than one place before getting stopped.

They do that in the modern era, too.  But RRers have a variety of terms for when a train comes apart.  I don't think any one is more correct than the other. 

[Euclid]

When I saw the phrase, “broke apart,” I imagined the train “breaking up” into many pieces like an aircraft for instance.  I think the most appropriate and most used term by railroaders is “break in two” or “broke in two.”  The word “break” does not have to mean failing by damage, although it can and often means that. 

 

“Break in two” suggests a separation for any reason including breaking a knuckle or pulling a drawbar.  But it can also refer to simply becoming uncoupled due to vertical bounce.  The term “separation” is adequate, but it sounds a little too clinical, like referring to a “head-on collision” as “making contact.”

In the link and pin days, trains sometimes broke-separated in more than one place before getting stopped.  So one might say the train “broke in two in two places”; which would amount to “broke in three.” 

And sometimes, the broken sections would come back together and "make contact" with each other.

[blue streak 1]

Thought----  This train separated at 124 MPH and somewhere brakes were applied either regular or emergency.  However the now two sections stopped close enough to not cause all connections between the cars to separate.  How in the world did the two sections make such an even stopping ? ?   If that did happen really gives high marks to the engineering of the Acela-1s.  Boggles the mind unless am missing something.

[jeffhergert]

Overmod

I concur with Ed, Paul, and Amtrak that 'separation' is the correct word.  It is my understanding that very little except one drawbar pin is physically damaged at all ... for which I am reverently grateful.

'Coming apart' made me think of Oliver Wendell Holmes' equally expensively built and sophisticated shay.  Not a happy analogy!

 

But train separation would even be better.  Car separation makes me think of bodies strewn everywhere along the right of way.

It probably doesn't matter anyway.  The reaction of the general public can probably be broken down into one of three attitudes.  1.  "We spend too much on Amtrak, and it still has accidents and is unsafe.  We should shut it down."  2. "We don't spend enough on Amtrak and this is what happens when you underfund it."  3. "What's Amtrak?  You mean there are people who still ride things we used back in the Stone Age*?"  There maybe stragglers with views in between these three, but I feel most hold one of those three views.

Jeff

*Stone Age - Before the internet and/or smart phones.

[Overmod]

I concur with Ed, Paul, and Amtrak that 'separation' is the correct word.  It is my understanding that very little except one drawbar pin is physically damaged at all ... for which I am reverently grateful.

'Coming apart' made me think of Oliver Wendell Holmes' equally expensively built and sophisticated shay.  Not a happy analogy!

[gmpullman]

Deggesty

Could we say, "The Acela came apart?"

Agreed 

Amtrak said it best:

“We are currently investigating the cause of the car separation, inspecting every Acela trainset, and taking any necessary actions to prevent a reoccurrence,” Abrams said in a statement. [Amtrak]

Regards, Ed

 

[tree68]

[Paul of Covington]

   I vote for "separated."

[Deggesty]

tree68

As has been noted, the drawbar appears to be intact, leaving one to wonder what happened to the pin.  I have no idea how the pin goes in, nor how it is secured.  I would opine that that is the key to the question.

I agree that "broke" isn't exactly the correct term, but "uncoupled" doesn't exactly fit either.  It's probably closer than "broke," though.

 

Could we say, "The Acela came apart?" I'm glad there was no such mishap last spring when I went up to Boston from Washington one day and back down the next day--just to ride Acela. (I, of course, had no opportunity to examine the connections.)

[blue streak 1]

Whatever caused the train to separate is to be determined.  "IF" it was a broken part because of metal fatigue or a hidden part not subject to 100% NDT then we will see a rapid testing of any associated part.

Of course locating any broken part if there is  one will be a major effort.  A lot of track walking.

[tree68]

As has been noted, the drawbar appears to be intact, leaving one to wonder what happened to the pin.  I have no idea how the pin goes in, nor how it is secured.  I would opine that that is the key to the question.

I agree that "broke" isn't exactly the correct term, but "uncoupled" doesn't exactly fit either.  It's probably closer than "broke," though.

[jeffhergert]

I think "uncoupled" is a better description than "broke apart", even if it's not 100% accurate.  I first thought reading this something to the car bodies themselves happened.  Now if it had been said to have "broke in two" or that the train had "separated" I would have immediately recognized what happened. 

It's not unusual for freight equipment to have a pin break and allow the entire drawbar/coupler to fall out.  I would expect passenger equipment gets more frequent inspections than freight equipment.  Still, it could have been inspected last week and still have failed this week.  Now if it had just been inspected and replaced last week...

Jeff

[Cotton Belt MP104]

......question:  anyone know?   pin inserted from below (hope not, but would hope flange of top insertion would at least have some failsafe factor if fastner on bottom failed   .......  Posted by 7j43k on Tuesday, February 06, 2018 2:22 PM It's pretty clear the drawbar didn't break. Maybe they should drop the pin down from above, instead of inserting it from below. Then it CAN'T drop out.  endmrw0206181930

[gmpullman]

Overmod

That term is not 'appropriate' in the least for drawbar-connected equipment.

I wrote my reply before actually seeing the photo of the drawbar connected units.

In my mind I had "semi-permanently" coupled (i.e. twin-unit diners and the like).

Still, uncoupled sounds more likely than broke apart but this is simply semantics. However it is certainly true that they indeed broke apart.

I'll be more careful with posting such ill-informed comments in the future.

Overmod

It's a breakage, pure and simple.

I do recall separating a steam locomotive drawbar. There was a primary drawbar and a secondary backup drawbar. The retaining pin(s) was (were) shoved up from below, then a substantial retaining plate slid into slots for the purpose, then the retaining pin allowed to drop back in place where a pilot hole in the retaining plate, plus several bolts, kept the plate from working out.

I can't say if the failure was the pin itself (the drawbar eye looks to be OK as viewed from the photo) and I don't know the mechanics of the pin retaining system. It would appear that it is not failsafe.

It has been a few years since I've visited WUT but at the time I seem to recall seeing the Acela platforms and I thought there was a way for car inspectors to have access to the "underpinnings" of the equipment, similar to what some diesel shops have.

Can anyone with more knoweledge of this elaborate? I'm wondering what the pre-departure inspection consists of. Years ago, of course, "car-knockers" would make frequent use of their hammers to "sound" brake beams, nuts, pins and the like.

 The sections of ther train came to a stop with an approxamately five-foot gap between the equipment. Presumably with the train-line still intact. Sparking was reported which I attribute to the high voltage cables becoming separated.

Did the engineer make a heavy service application? Were the brakes automatically applied when a loss of control circuitry was detected? If the train line was still intact I assume an emergency application was not made due to a loss of brake pipe pressure. Or does the Acela use a braking system similar to the proposed "electro-pneumatic" systems which were once under development in the late '30s?

Cheers! Ed

 

[Overmod]

BaltACD

I wonder how many steam engines came uncoupled from their tender. I am certain it wasn't a particularly common happening, however I expect that it happened more than a few times.

The interesting thing here is the provision that was often made for this.  (I believe there is a very good sequence of photographs showing and discussing the arrangement on one of the restored PRR K4s).  The pins on locomotive and tender were sized and inspected so that a drawbar, rather than pins, would be the part to suffer failure, and while there were two drawbars one of them was intentionally made with holes a bit elongated, so it 'floated' in normal action of draft or of the tender buffer, but would smoothly take up the tractive effort of the engine should the primary drawbar part suddenly or begin to suffer undue elongation.

Backing up both drawbars was a safety chain, although I am not sure that the acceleration of a large heavily-loaded modern locomotive might not produce enough differential to snap such a chain when the slack ran out.-

Returning to the Acelas: I'd think there would be a PM interval for inspection and NDT of the drawbars, eyes, pin structure, and pin seats.  And a traceable audit trail relating to all that work.  Be interesting to see what comes of this.

[pajrr]

Don't you know that PTC would have prevented this? Afterall, suddenly EVERY train accident could have been prevented by PTC (This is just pure sarcasm. I can't resist)

[Overmod]

gmpullman

At least the Baltimore Sun had the decency to use the more appropriate term "Uncoupled"...

That term is not 'appropriate' in the least for drawbar-connected equipment.  And it isn't a pull-apart because excessive tractive force effects didn't cause coupling parts to fail.  It's a breakage, pure and simple.

I wouldn't use 'broke apart' to describe either the Challenger (which blew apart) or the Columbia (which progressively disintegrated due to initial failures in completely improper internal structure for a hypersonic aircraft).  You might as well say Katrina was blustery, or a hydrogen bomb makes a pretty good bang.

[BaltACD]

I wonder how many steam engines came uncoupled from their tender.  I am certain it wasn't a particularly common happening, however I expect that it happened more than a few times.

Acela's have been operating for 18 years without me ever hearing of this happening.  

[Overmod]

In a new twist on newsworker language, note that the drawbar connected 'two trainsets', which to me suggests something very different than what I think the writer meant to say.  It has also left me wondering what the cause of the 'sparking and smoking at the head end of the train' might have been.

There may be something highly interesting to come out of this from an engineering perspective.  If I remember correctly, Acela power is applied 'top and tail', so the actual tractive effort through that drawbar should really not be that great, although it might change value comparatively quickly and therefore experience some shock if there are differential control changes between power or braking on the sections to either side.  I presume they will hunt for and find the pieces of the missing pin, and it will be interesting to see the metallurgical and physical analysis as well as wear or distortion patterns on the drawbar eye.

Perhaps this is a situation like the cracking spokes on brake rotors or deflicted equalizer beams on Silverliner Vs, and other pins on Acela equipment are similarly fatigued or even close to failure.  Is there a high-speed rail equivalent of an airworthiness directive?