Accident in the subway.

Question

I know that it is very dangerous ( lethal ) to touch the "third rail" in the subway lines, what I dont know is how bad the damage to the body would be.... also,how much electricity is needed to operate the subay trains in london? here in mexico city the trains operate with 750v.

Answer 1

i had an accident in Subway one day. I spilt my diet coke all over my meatball sandwich.

Answer 2

I used to work with a driver on the London Underground who, if ever he had a headache, would go and intentionally kick the positive rail. He swore it cured his headache although I would never recommend it as a cure-all myself - more like an end-all !

Please note also, that on the London Underground, equipment is already in place for future use - and new trains on order - which will allow it to run at 750V instead of the current (no pun intended!) 630V.

Answer 3

In southeastern England, conventional above-ground trains running from London down to the south coast use a 3rd-rail supply system with return via the earthed running rails, as can be seen in this picture:

http://www.kentrail.co.uk/Staplehurst_We...

The supply to the 3rd rail is nominally 750V DC, although with all these systems it's important to realize that the voltage will increase or decrease somewhat with the varying demand from trains.  During quiet periods the voltage could rise to 800V, while during periods of high demand it could drop below 700V.  

There was an accident reported in the press just a couple of weeks ago in which a foreign tourist at Vauxhall station (south London) wandered down onto the tracks looking for somewhere to relieve himself and was electrocuted when he contacted the 3rd rail:

http://www.dailymail.co.uk/news/article-...

The traction current supplied to most of the London Underground (subway) system is nominally 630 volts DC.  Unlike many other systems in the world, however, London Underground uses both a 3rd & 4th rail to supply current to the trains.   You can see the track arrangement in these pictures:

http://www.trainweb.org/tubeprune/72%20T...

http://www.trainweb.org/tubeprune/Tube%2...

http://www.trainweb.org/tubeprune/59%20T...

The 630V DC is earthed by resistors to give a one-third/two-thirds split, which means that in normal operation the positive (outer) conductor rail is at about +420V while the negative (central) conductor rail is at about -210V with respect to earth.    This system was chosen many years ago for various technical reasons, although in earlier times different branches of the subway system had some other basic 3rd-rail arrangements.   One advantage of the split system is that in the event of an earth fault on one side of the supply trains can continue to run, with either the positive or the negative conductor rail rising to the full 630 volts with respect to ground.

There are some stretches of track in the outer reaches of London where Underground trains run on the surface and share track with traditional above-ground trains.  On these stretches, the central conductor rail is earthed and the outer rail runs at the full supply voltage, thus enabling both subway trains with their 3rd/4th rail pickup shoes and regular trains with just 3rd rail pickup to use the tracks.

Answer 4

Most DC lines will not kill, they cook you.  A normal average MALE human will survive touching the third rail DC system unless they are touching a vital organ, wet, or have a condition that has increased there chances of not being able to pull away from the rail.  Unfortunatley most Females that touch the rail do not have a second chance for some reason, which has been proved by facts.

I have seen someone fall twice onto a 750v DC line here in South England and survive only to be hit by a 70mph train whilst trying to recover.  I have also been jolted by the 750v rail as part of My own experiences as a rail worker on a couple of times when out walking the track and been burnt, luckily never seriously, but it does hurt even for the breifest second where you touch it accidently.

The poblem with DC is that is does attract and make flesh stick to the rail unlike AC which repels, as I said it will cook you inside and the pictures I have seen of bodies that have been fried are not nice, most luckily are killed as the train does run over the body, but not a pleasant way to go.

ALWAYS assume the rail is live is the motto of anyone who goes near the line, no matter which rail you cross or touch.

Good Luck

Answer 5

It's lethal... you pretty much keel over as the heart stops due to the shock, and the convulsion caused by the current can break bones.

http://www.redorbit.com/news/business/99...

According to Wikipedia, third-rail in GB varies from 600 to 850V DC

http://en.wikipedia.org/wiki/Railway_ele...

Answer 6

In NYC the train operates at 600v.

that's enough to basically kill a man (not just hurt him).  It isn't just the voltage.  It is that the third rail can supply an incredible amount of current.

===

Try this experiment (very carefully).  Tie 2 nail to 2 wires of the electric plug (+ and minus).  Insert the nail to the ends of a hotdog.  Then plug it in to the wall.  Watch the hotdog cook.

VERY DANGEROUS.

Good Luck..

Answer 7

Third rail is almost always 550-900 volts DC.  Higher doesn't work when it rains.  600V tends to be the most common since it's the highest older DC motors could handle without shorting internally.

That's enough to kill someone dead, obviously, via shock and burn. If you lived, you'd be visiting a burn ward.

You gotta realize, 600VDC is weird.  It doesn't behave like the 110 volts AC (or even 230 volts AC) you're used to.  For one it's a lot higher voltage, so it wants to jump insulators and switches.  For another it's DC, which means the voltage is continuous one direction - it doesn't stop and change directions 60 times a second.   When a 600VDC arc strikes, it never stops.  It just burns until there's nothing left to burn.