Being strictly a west coaster I’ve never seen a third rail electrification. I’m wondering how do they protect people from getting zapped? And what voltages do they use on them?
I grew up along the Chacigo Aurora & Elgin west of Chicago. I was constantly drilled never to go near the third rail. The right-of-way was fenced, but the third rail was easily accessible at every one of the frequent grade crossings. The only protection was something resembling a cattle guard and a small white sign reading: “Danger Electric Current Keep off Tracks” in red letters. CA&E used 600 volts dc.
i heard, that only when a train is coming is the third rail any danger, now, i havent, nor do i want to, test this theory, but just hear say…
In Sacramento Northern third rail territory, during the first half of the 20th century, people were expected to be smart enough to stay off the track.
San Francisco Bay Area Rapid Trainset (BART) is surrounded by substantial fences.
People don’t get electrocuted because the steel wheel of the transit cars against the steel rail provides an adequate ground. The juice itself is potent, as any Chicago Transit Authority employee can tell you who has had to “sting” a recalcitrant car over a switch, say.
The question came up some years ago in Chicago as to why the EL trains run even though snow is up to the third-rail and sometimes higher, before a train comes along to dust it off. The answer was that snow has a different molecular composition than water and doesn’t conduct instant blazing death. But if WATER were all the way up to there, well, the consequences might not be so pretty.
About ten years ago, drunk and in the middle of the night, a young man was electrocuted when he urinated on the track and it came in contact with the third rail. Guess where the current entered his body…
Some third rail electrications have protection boards, examples are the LIRR, New York, Boson, and Phila subways. Others don’t or didn’t. The Chicago system, CA&E, Larual Line, and Sacramento Northern. Generally, the third rail is live all the time, so don’t touch. I understand one interurban line did use about 1000V on its third rail but generally it is 600 or 750 volts dc.
You are so so so wrong, the third rail is always live. Every year a couple of people are electricuted and their mates have said this, it’s a common misconception.
Generally 3rd rail electrification will not be above 1000 Volts to prevent arcing due to the proximity of the rail to the ground. Luckily the large cross section of the rail means that the large currents neceswssary to power a train at these voltages can be easily handled.
Ok. First post and I live over the pond.
There are running boards and various designated places where employees can cross if you are out working on the track. normally id they take a possession of the line for engineering purposes the juice is turned off by the ECO.
For everybody else - its palisade fencing.
I think it holds 660 volts. Also it you are wise you stay away from them. If you are silly & then decide to touch one well then you become electrified real quick. In the NYC subway system & PATH the top has a board over it but the sides have to be open so that the shoe on the car meets the 3rd rail so the car can obtain electricity [:o)][:)][:p]
[quote]
Originally posted by chad thomas
LIRR has an overrunning third rail with a cover above the rail and Metro North has an underrunning (contact from beneath) third rail which is insulated on the top and sides. Most rapid transit systems use an overrunning third rail which is completely uncovered and allows the use of gravity contact third rail shoes. 600-660 volts DC is the most common potential used.
The Washington D.C. area metro uses a 3rd rail. Where it’s above ground, it’s completely fenced - no grade crossings. In the station you would have to jump down from the platform to get to it. Possible but not likely.
Enjoy
Paul
Some of you mention grade crossings. How is that possible?
How is third-rail compatible with grade crossings? With great trepidation.
About a month ago here in Chicago, the CTA took the Skokie Swift (a vestige of an old interurban line) off of catenary. Previously it had shoe’d off third rail from the terminal on the Evanston/Chicago border but then, as it entered Skokie where the grade crossings are, would “pan up” and go to overhead. Thus, at grade crossings, there was no third-rail for Skokie.
Presumably the citizens of Skokie are satisfied that third-rail is safe enough. Of course, the right-of-way is fenced off, but there is no particular cloak built into the third rail itself to keep it less accessible to people’s feet, etc.
When there’s no action, little white “horse gates” screen pedestrians from the track itself. When the wigwag starts to flash, the gates fold back and make it possible for the train to pass thru.
This WAS, as far as I know, the only RT system in N. America to have a switchover in modes of delivery “on the run.”
Do you know of any others, past or present? [?]
Chad,
They simply leave a gap in the third rail across the crossing. Most trains are long enough to still connect, but if they are not, they simply coast across. CA&E even carried a long cable just in case a car stalled in mid gap. For older cars on the CA&E, the lights flickered, but newer cars carried batteries.
Brewer is right, and I should have mentioned that particular aspect, that third-rail never runs clear across intersections with sidewalks or roads. And since it is gated off most of the time, it is considered safe enough. After a month of the new third-rail mode, Skokie hasn’t had any incidents, nor have they had the catenary fall in bad weather–so far, so good.
Thanks guys, I’ve been pondering how you could have a third rail across a road. Now it makes sence. It didn’t dawn on me that you could have multiple contact points. Now I feel kind of stupid[:I]. I also didn’t know Sacramento Northern used third rail. I thought they were overhead only.
Don’t “feel stupid” – it’s hard to envision a third rail at ground level and even more difficult (in my case) to describe it.! [8)][:p][8)][:p][8)]
Chad:
Closer to you: LA Metro “Red Line” (Subway mostly) is third rail…their surface yard is east of Amtrak’s Redondo Junction facility on the same side of the LA River…Fenced, but those fine LA citizens still manage to get inside the fence in attempts to steal copper and other saleable metals.
MC, I’ve been down there a couple of times to check out the Amtrak at Redondo Jct. I never noticed the third rail. The Metro doesn’t really intrest me so I pay it little attention. A friend of mine used to have a studio at Santa Fe ave. & 4th street and I used to spend a lot of time down there. I see the studio all the time on TV and in the movies as they do a lot of filming in that area along Santa Fe ave, including one of my favorite movies “Tough Guys” starring SP4449.
Mention above that rainwater or snow aren’t very effective conductors of electricity is basicly true. Water holding salts in solution is a much different matter, therefore do be careful where you go.
If you want to see a rather spectacular display of electrical arcing, check out the operation over an uncovered third rail system with a top of the rail pick-up in an ice storm. I think that is part of the reason the LIRR covered the third rail. Once saw that happening on the CTA.
At a later time, a bad ice storm coating the overhead catenary on the Illinois Central Electric put the service to a standstill. I am not sure this is true, but someone said that after the icing stopped, lineman working from a platform rigged atop a diesal engine used baseball bats to nock down the ice. Electirc power off, of course.
Jay