How do you avoid getting electrocuted on a subway track?
January 4, 2007 8:34 AM   Subscribe

After reading this NY Times story of a man jumping on the NY subway tracks to save a man who had fallen there after a seizure: How do you avoid getting electrocuted on a subway track?

From the MTA NYC Passenger Safety FAQ: "No matter what situation arises, keep off the tracks. Tracks contain 600 volts of live electricity. If you drop something on the tracks, go to the station booth and tell the agent."

So how exactly did Wesley Autrey avoid getting electrocuted?
What part of the track exactly must you avoid if such a situation arises?
Is electrocution automatic if you touch the electrically-conducive part?

This question is a bit close to chatfilter and I don't intend to jump on a subway track ever, but I am genuinely curious and the question seem to respect the guidelines as I've read them. If it doesn't, please delete.
posted by jchgf to Grab Bag (22 answers total)
 
Best answer: The third rail.
posted by lovejones at 8:35 AM on January 4, 2007


Just don't touch the third rail. Or maybe it's the first. Oh crap, I'm not sure it isn't the second. And I think that by "first" they mean the one closest to you. I think. It may be the other way around.

Anyhow, just don't touch one of the rails and you'll be fine.
posted by sourwookie at 8:38 AM on January 4, 2007


No, just the third rail. The two tracks that the wheels of the train move on don't carry a current.
posted by lovejones at 8:42 AM on January 4, 2007


Best answer: That's right, its the two closest to you (in every station I've ever been in, at least) that are not charged. You can tell the difference in the third rail in that it is not a weight-bearing rail designed for a train wheel to rest on. Many times it will have a sort of covering over it - presumably to allow a person to step on it without consequence of death. But I imagine if you stick your finger on it from the side, you're not going to need to worry about being hit by that train.

I once had a boy-hood friend who stopped to take a leak on a fence in the middle of some fields we were out exploring, and found out quite unpleasantly through his stream of fluid that he was doing so on an electric fence. I always wonder if this could happen to a bum pissing on the tracks. That would be a sight to see.

So how exactly did Wesley Autrey avoid getting electrocuted?

As I understood it from the article, Wesley was in the slight gap between the two main rails that a person can apparently lay in and avoid being crushed to death. In most stations this gap has been cut into the railroad ties between the rails.
posted by allkindsoftime at 8:45 AM on January 4, 2007


The third rail is the one furthest away from platform and it has a wooden kind of "roof" over it so workers don't accidentally brush it with their feet when stepping over it.

That having been said, avoid going into the tracks as much as possible.
posted by Divine_Wino at 8:45 AM on January 4, 2007


Best answer: You can usually tell which is the live rail, because it accumulates carbon grime and it's supported on insulators.

Also, you can touch the live rail as long as you're not grounded. For example, in theory, you'd be safe jumping on it with both feet. It'd probably be wise to practice on a dead rail first, though.
posted by veedubya at 8:45 AM on January 4, 2007


I think among railway workers, the rule is "never touch any rail, reguardless of whether it is the live one or not". The idea being that if you get in the habit of avoiding contact with all rails, you are a lot less likely to accidentally step on a live rail you thought was a safe one.
posted by EndsOfInvention at 8:53 AM on January 4, 2007


Not all subway lines have a third rail system. Some are powered overhead. The London Underground has four rails (two powered).
posted by loiseau at 8:56 AM on January 4, 2007




Mythbusters actually tested whether relieving oneself on the third rail could electrocute you. They came to the conclusion that from a reasonable distance the stream breaks up too quickly to carry the current required to kill you.
posted by phrontist at 8:57 AM on January 4, 2007


I always wonder if this could happen to a bum pissing on the tracks. That would be a sight to see.

They investigated this on mythbusters. Turns out that you have to stand really close or your urine stream will separate into droplets and not conduct electricity.
posted by fvw at 8:57 AM on January 4, 2007


If I recall, didn't the build team later shock the bejeezus out of Adam with the same gizmo they used to test the fence theory, thus casting a slight bit of doubt onto their earlier results?
posted by sonofslim at 9:22 AM on January 4, 2007


Mythbusters actually tested whether relieving oneself on the third rail could electrocute you. They came to the conclusion that from a reasonable distance the stream breaks up too quickly to carry the current required to kill you.

Mythbusters has a history of being wrong. Mythbusters concluded that bullets fired up into the air cannot kill people on their way down. Despite Mythbuster's conclusion, falling bullets regularly do hurt and kill people. A quick review of medial literature would have confirmed the myth.

I take Mythbusters' conclusions with a grain of salt.
posted by malp at 9:27 AM on January 4, 2007


Electric fences typically produce a 3 millisecond pulse of 2000 to 10,000 volts with low (non-lethal) amperage. The point of the short pulse is to let the animals remove themselves from the fence.
posted by weapons-grade pandemonium at 9:35 AM on January 4, 2007


I take Mythbusters' conclusions with a grain of salt.

That's fighting talk around these here parts.
posted by veedubya at 9:37 AM on January 4, 2007


I take Mythbusters' conclusions with a grain of salt.

Adam Savage of Mythbusters participates on MeFi, actually.
posted by WCityMike at 9:54 AM on January 4, 2007


Um, malp, check again. From the Mythbusters episode:
The bullet test. Here we have an interesting result: confirmed, plausible AND busted. How can that be, you ask? Confirmed, since there are clear cases of bullets fired at a trajectory killing people miles away. Plausible, since it's possible a bullet fired straight up may have some trajectory to it, just enough to maintain its killing velocity. Busted, since a bullet truly fired straight up will fall to Earth with barely enough velocity to give you a bruise."
Also falling bullets was an earlier AskMe. /derail.
posted by yeti at 10:25 AM on January 4, 2007


For example, in theory, you'd be safe jumping on it with both feet.

As are the non-dead birds that sit on high-voltage lines.
posted by stupidsexyFlanders at 12:11 PM on January 4, 2007


When one of those non-dead birds chooses to put a foot either side of an insulator, though, they become very surprised-looking fully-dead half-birds very very quickly!

The sound of a crow briefly shorting out a 22kV power line is once heard, never forgotten.
posted by flabdablet at 5:27 PM on January 4, 2007


As are the non-dead birds that sit on high-voltage lines.

But, as addressed in the Electrocution in a pool question, the definition of a single point of contact can become very strained. Bird's feet are only separated by an inch or two, but if a human was hanging onto a wire with both hands, the separation might be 3 feet. Probably still safe, even on extra high voltage lines, but it starts to get complicated..
posted by Chuckles at 5:34 PM on January 4, 2007


Something else to keep in mind, should you ever find yourself on a subway track with an oncoming train, is that many subway platforms have a little "negative space" under the platform. I know DC's subway is like this. So if you were on the tracks, you could duck into that little area and be safe.

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posted by Alt F4 at 7:38 PM on January 4, 2007




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