Saturday, April 3, 2010

Freight Train vs Tornado



Above is absolutely spectacular footage from the rear-facing unit of a Union Pacific freight train encountering a tornado on January 7th of 2008, in northern Illinois on former Chicago Northwestern tracks. News indicated that twelve cars of the 1,880-ton train were blown off the track though you can see, on screen, the locomotive stays upright due to its weight.

Initially the train appears to be moving at good speed (I'd estimate 30+ mph). You then notice the trees at the periphery of the screen moving and blowing, then the rain squalls hit at roughly :35 seconds, with very heavy rain and winds at :55 seconds. The grain car starts to roll left at about 1:10. The locomotive, slowing now and crossing a trestle, is struck by a tank car which then rolls right, followed by a boxcar. The volume is low; if you increase the volume the video becomes even more frightening.

One tank car, containing ethylene oxide, requiring the evacuation of the unincorporated town of Lawrence, Illinois.

Links:

- Trainorders.com discussion here;

- KOMO News here;

- National Weather Service link here.

MP154

5 comments:

Greybeard said...

VERY interesting stuff.
I have no idea what an empty boxcar weighs but to do the job they must do they have to be built like tanks, and therefore must be fairly heavy. But a wind blowing directly against the slab surfaces of one would exert quite a force. It would be interesting to talk to someone about the dynamics of the moving train and being hooked up to other cars/the locomotive...
Seems to me that would also provide some stability. So derailing these cars had to have taken quite a shove.
I wonder if a tornado has ever derailed a locomotive?

Milepost 154 said...

Empty, the average 100-ton boxcar weighs about 63,000 lbs., with a 263,000 lb gross limit. A boxcar is, generally, not ballasted real well and the weight could be located most anywhere in the car itself. Clearly, in the video, the wind is blowing right-to-left. It appears, to me, that some of the cars in the middle of the train blow over first, then the grain car closest to the camera.

The high speed of the train in concert with the forceful winds wouldn't help because, as you can see, at that given train speed you're getting some harmonic rocking of the cars on the track.

UP has road cams in all their units now, and have had them for some time. Next opportunity you have, look on the Conductor's side of the cab window (left side of the cab) and you'll see a white cam through the window.

In terms of locomotives, this appears to be a more modern-type loco, with its grab irons indicating, to me, that it's likely a GE. If, for example, it's a GE C44ACCTE, it goes for about 416,000 pounds or 208 tons. The difference being that most locomotives are ballasted low with either lead or concrete.

"Locomotives are typically manufactured to distribute weight symmetrically to the trucks and then to the axles of the trucks so that relatively equal portions of the weight of the locomotive are distributed to the axles. Typically, the weight of the locomotive and the power rating of the locomotive determine a tractive effort capability rating of the locomotive that may be expressed as weight times a tractive effort rating. Accordingly, the weight applied to each of the axles times the tractive effort that can be applied to the axle determines a power capability of the corresponding axle. Consequently, the heavier a locomotive, the more tractive effort that it can generate at a certain speed. Additional weight, or ballast, may be added to a locomotive to bring it up to a desired overall weight for achieving a desired tractive effort capability rating. For example, due to manufacturing tolerances that may result in varying overall weights among locomotives built to a same specification, locomotives are commonly configured to be slightly lighter than required to meet a desired tractive effort rating, and then ballast is added to reach a desired overall weight capable of meeting the desired tractive effort rating." (http://www.faqs.org/patents/app/20090031915)

Further, locomotive fuel tanks are commonly slung low, close to the rails, between the truck assemblies. Modern locomotives customarily carry a minimum of 4,000 gallons of diesel fuel, up to 4,500 gallons. One gallon of diesel weighs about 7 pounds in the summer, about 7.2 pounds in the winter. At 7 pounds X 4,000, a full fuel tank = 28,000 pounds or 14 tons.

Hence, this time, the locos stayed mostly upright. Now you know why.

MP154

Well Seasoned Fool said...

Thanks for posting this. I doubt I would have seen it otherwise. What a mess for the railroad workers to clean up.

Tornados flat scare me. Business travel took me by Greensboro, KS after their first big one and before the second. The destruction was beyond what I thought possible.

Bloviating Zeppelin said...

Anyone notice that the tank car approaches canted slightly left on the track, strikes the front of the loco, then caroms off to the RIGHT? I submit: that's one TOUGH locomotive.

BZ

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