"Earth Fault" on CSX

[Glorious NSE]

It applies the brakes on the trains as well, the difference is that your truck is effectively a one car train and the trains usually have lots of cars!

 

The brake application travels down the pipe as the air escapes through that small hole in the end of the pipe so in terms of the truck it affects the whole vehicle almost instantly - on the train it affects the first vehicle instantly and then moves down the train, so what you see early on is the leading cars behind the split having their brakes locked on but the rest of the train which isn't yet braking merrily pushing them along.

 

On the tornado vid the loco's stop quickly, i'd guess a combination of a quick brake propogation from wherever it splits (only a few cars back from the loco's?) - better braking force on loco's versus freightcars, plus the drag from the derailed cars and i've a feeling that lead covered hopper might even have dragged the rear loco off as well (it does bounce around a bit) stops the lead portion pretty quickly - but the rest of the train (likely many times the size of the front portion) still has lots of momentum and it's likely that the brakes will still be applying their way back down the train - so it catches up with the now-stopped first bit really quickly!

[Grovenor]

Going back to the derailment cause, did you all miss this bit early in the thread?

(the fans interpretation in the comments to it is that it was the rail *after* the frog that turned over)

Spiked track in the US is prone to the outside rail turning over when the side force pulls the spikes on the inside, everything in the vid supports this theory.

Regards

Keith

[F-UnitMad]

It applies the brakes on the trains as well, the difference is that your truck is effectively a one car train and the trains usually have lots of cars!

 

....

Thanks for the explanation!

 

Re Grovenor's post; the actual You-Tube clip also has comments that the de-rail was on the curve after the turnout frog, too. One states that it was a little-used spur that had had very little maintenance or use, and the rails spread under the weight of the hoppers.

I don't know for sure, but I should imagine the hoppers have a higher weight-per-axle than the locos..?

[Glorious NSE]

I'm very aware of being in "speculation mode" here, but the other thing with US covered hoppers is that when loaded they have a very high centre of gravity, so are prone to rocking from side to side* - it's not inconceivable if they were loaded cars that "got a bit of a rock on" that they may have been putting far more sideways force on to the rail beyond the point than the heavier loco's had - regardless of what the axle weights were.

 

* violently enough that some railroads have rules on not allowing certain trains to run at certain speeds where harmonic rocking can build up momentum to lift wheelsets and cause a derailment!

http://www.transportationu.com/articles/hrr_01.html has a bit of background info about the wonderfully titled "harmonic rock off"

[F-UnitMad]

I'm very aware of being in "speculation mode" here, but the other thing with US covered hoppers is that when loaded they have a very high centre of gravity, so are prone to rocking from side to side...

I'd agree with that - the clip shows it didn't take much sideways sway to topple the first car over, dragging others with it.

[melmerby]

I'd agree with that - the clip shows it didn't take much sideways sway to topple the first car over, dragging others with it.

 

I was amazed at the ease at which they tipped over considering the low speed. That's why I commented about the UK situation where I would have expected wagons to stay upright unless they went off on an embankment.

 

I suppose the wheels, once away from the solidity of the ties, would have dug into the surrounding earth pretty quickly.

 

Keith

[Steven B]

Am I the only one who finds the presence of railfans, with a video unusually following vehicles though a turnout, rather than the locos heading away, slightly suspicious?

 

Filming the whole train is very common in the US - most of the videos on YouTube cover the whole train.

 

I wish more British rail fans did this. Taking photos/a video of the whole train, not just the loco and the first couple of coaches/wagons would make modelling prototypical rakes much easier.

 

Happy modelling,

 

Steven B.

[dave1905]

I was amazed at the ease at which they tipped over considering the low speed. That's why I commented about the UK situation where I would have expected wagons to stay upright unless they went off on an embankment.

 

I suppose the wheels, once away from the solidity of the ties, would have dug into the surrounding earth pretty quickly.

 

How much does a UK wagon weigh?

 

Those cars weigh close to 286,000 lbs on 4 axles, that's almost 18 tons per wheel. The location is the Mississippi floodplain in Louisianna so the soil is a couple hundred foot thick layer of silt and clay that is a mere feet above sea level, so the water table is only a couple feet down. You betcha that if the wheels go off the ties they are going to bury up in a minute.

[pH]

Those cars weigh close to 286,000 lbs on 4 axles, that's almost 18 tons per wheel.

I had to think about that a few times - it didn't seem a lot. Then it clicked. I'm used to seeing weights quoted as per axle - so that's a 36 short ton (32 imperial ton) axleload!

[ringo]

Looking at the way they fell over, the bogies dont seem to be captive, so once lift clear of the centre casting, theres no where for the wagon body to go other than fall over.

 

In the Uk (and most of europe), the bogie is captive to the body, this helps in that it remains attached to the body and thus the centre of gravity assists in keeping the wagon upright.

 

Also, look at some of the other clips of standard North American rerailing practices.....Having been involved with rerailing and recovery for nearly 30 years on BR and privatisation, it makes me cringe to how their experts rerail.....a real gungho way of doing it, I think they need some MFD training.....

 

R

[BR60103]

Yes. the cars just sit on a pin sticking up from the bogies; not even a split pin with knobs on the end.

Passenger cars and tenders have chains to the bogies, but I think these are more to keep them in line with the tracks when they derail.

I also believe that some bogies are just sitting on the bearings and the axles may go off separately.

[trisonic]

No "split pin with knobs on"? Damn.

We should also look at how main gun turrets are fitted to battlefield tanks too whilst we are at it.

 

Best, Pete.

[melmerby]

How much does a UK wagon weigh?

 

Those cars weigh close to 286,000 lbs on 4 axles, that's almost 18 tons per wheel. The location is the Mississippi floodplain in Louisianna so the soil is a couple hundred foot thick layer of silt and clay that is a mere feet above sea level, so the water table is only a couple feet down. You betcha that if the wheels go off the ties they are going to bury up in a minute.

 

How about 102t (224,808lbs) on 4 axles, that's about the biggest I can recall.

 

Keith

[CraigZ]

Yes. the cars just sit on a pin sticking up from the bogies; not even a split pin with knobs on the end.

Passenger cars and tenders have chains to the bogies, but I think these are more to keep them in line with the tracks when they derail.

I also believe that some bogies are just sitting on the bearings and the axles may go off separately.

 

Pretty much correct, yep...I don't think modern passenger cars use chains but I'm not certain.

 

And for many years bogies/trucks have relied on gravity to keep the axles/bearings in place. The Atlantic Coast Line specified trucks with something called Stein retainers that were effectively extended jaws on the sideframes with a pin that slid under the bearing. The sideframes are still pretty easy to find in service on CSX cars, but haven't had pins in ages. Example attached...and for years only some brass trucks could be had with this detail. Kadee's done them now and they're gorgeous: http://www.kadee.com/htmbord/page560.htm

 

 

[dave1905]

Some truck side frames have a small clip that keeps the roller cage in the side frame, but basically gravity keeps the axles in the side frames. US freight rail cars just sit on the center plate with a center pin , but nothing is attached, all gravity.

 

Doesn't appear to be a problem since we have been running cars that way for the last 180 years. 8-)

 

Pretty much by the time you get a car unbalanced enough to start tipping over, whether the trucks are attached or not is not going to have any bearing on whether the car turns over or not. The weight of the car itself has more to do with it. A double stack with 2 large empty containers on it will roll over if 50-60 mph wind hits it broadside.