MistaMatthews
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50cm?? That's very different from the 9ft I was taught!
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How dangerous is the third rail?
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50cm?? That's very different from the 9ft I was taught!
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swt_passenger
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That 9 ft includes the reach of the tallest likely person. The safety distances quoted are from where you’re supposed to be standing...
As far as I know, the 9ft rule is for carrying things - e.g. a ladder - near OHLE, rather than the maximum arc distance.
The longest arc in perfect dry conditions is just under 40mm, but then there's airborne contamination, moisture and the fact that 25kV OLE is highly movable (unless it's of the solid bar type). Probably a tall person with an unbrella would be nearest to the limit. When standing near the edge of a platform in the rain with an umbrella, I've received a tingling ac shock from an umbrella, - probably the capacitance between getting on for 1sq m of wet nylon attached to a metal frame with me grounding it.
samrammstein
Member
This discussion brings to mind this 1950s London Transport safety film (4 mins 11 secs) I don't believe stepping between the conductor rail and running rail is recommended these days!
I've only had to step over it once, and was amazed at how big a step it is to step over the running rail and the juice rail at the same time.
I seem to remember the only advice given by the MOM was that it was turned off, but still not to touch it.
The first bit of crossing was from the cess to the 4 foot over just the running rail - going back was further up the line where the third rail had switched sides. It was certainly easier just going over one.
I don't think I appreciated how far the gap between them is, nor the vertical separation.
I also hadn't appreciated just how many large cables there can be in the cess!
I seem to remember the only advice given by the MOM was that it was turned off, but still not to touch it.
The first bit of crossing was from the cess to the 4 foot over just the running rail - going back was further up the line where the third rail had switched sides. It was certainly easier just going over one.
I don't think I appreciated how far the gap between them is, nor the vertical separation.
I also hadn't appreciated just how many large cables there can be in the cess!
Gloster
Established Member
If you had to cross the line the preference was to do it where there was a gap in the third rail. If there wasn’t a gap, then it was best to choose a place where the juice rail switched sides and you could go across diagonally, or somewhere with kicking boards. Failing that, at least check you had a flat area to step down on to on the other side. I have placed my foot between the running rail and the juice rail, but rarely and very carefully: the movements of my legs must have appeared slow-motion and exaggerated to any onlooker.
Treat it with respect, but not fear.
Treat it with respect, but not fear.
bramling
Veteran Member
I wouldn’t place my foot between the running rail and juice rail, must say it surprises me when I see people do it that way, but it seems to work for people.
IMO of the biggest dangers isn’t actually crossing live rails, but having an unrelated trip or fall and landing on top of it. There’s plenty of trip (and slip) hazards on and around the track. A good reason never to rush when walking on the track.
I agree that the risk of slips/trips onto the con rail is a bigger risk than crossing it. However, AIUI, the biggest risk (in terms of accidents reported), is stuff being carried touching the rail. Sometimes it can be as little as a strap handing off a bag.
bramling
Veteran Member
I presume that may be a factor in the (fairly) recent trend towards train crews having rucksacks rather than the traditional holdall-type equipment bags?
I can well imagine tools being an issue, seeing what p-way carry around with them it’s almost inevitable unfortunately.
Gloster
Established Member
We had it dinned into us to be careful with the wooden shaft or handle of tools: they should, if kept clean, be an insulator when dry, but could be a risk when wet.
Worth watching for the Keystone Kops ending !
Still disconcerting when you are standing near the edge of the platform in wet weather and sparks start coming off the ribs of your umbrella.
Philip Phlopp
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What 25kV AC OLE is "highly movable" then ?
P.S - Be afraid of pantograph horns far more than the OLE itself. There's a reason various boffin types are testing insulated horns...
You can poke the OLE with most modern umbrellas (did the EU mandate insulated shafts or some such) and sod all will happen.
As previously - don't actually try this at home. Or at a station with 25kV AC swaying about dangerously in the breeze...
richardsun
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I was also taught this on PTS/DCCR and it seemed like good advice. We tried both methods on a dummy section of track, and it seemed easier to keep balance and awareness of where your feet are, by sidestepping across the 3rd & running rails rather than doing a big forward stride over them.
Likewise, I remember a depot visit to Ashford in the 1980s where the guide took our group across multiple (10+?) third rail lines. Felt a tad uneasy stepping over each third rail at the time.
I would say you’re doing the right thing. I’m PTS trained in both AC and DC lines and although I don’t work in any DC third rail areas I hope I never do! Looking for gaps/safe areas to cross is what I’d be doing as well. Safety videos say if there is no alternative, step over both the running rail and third rail in one go; as I’m only 5ft 5in with little legs and the third rail is raised slightly, I don’t fancy my chances of making that step, especially with the possibility of clothing brushing against the third rail. Carry on being safe; I’d rather have my workmates giving me a bit of banter over it than trying to be “one of the lads” and risking electrocution.
While the voltage is less than an overhead cable, DC currents are like magnets so you will struggle to pull yourself away if you were unfortunate enough to make contact with the rail.
AC chucks, DC sucks! Stay safe!
While the voltage is less than an overhead cable, DC currents are like magnets so you will struggle to pull yourself away if you were unfortunate enough to make contact with the rail.
AC chucks, DC sucks! Stay safe!
Islineclear3_1
Established Member
Spent much of my (younger) life around depots/yards/signalboxes and cabbing. Even on official depot visits, there were sometimes little or no safety briefings apart from "Don't step on the juice rail..."; however in latter years of official visits, the juice was switched off.
Of course, walking up to a signal box or the line to get into an EPB cab in the dark winter months and the rain could be fun....
PeterY
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I really enjoyed watching the video, even from a nostalgic point of view. Basically common sense.
That comment was in the context of najaB's suggestion that 500mm was the minimum safe working distance from a live 25kV line. I was thinking of the oscillation that OLE endures when pantographs on fast trains pass. On more than one occasion, i've been waiting on the down fast platform as trains have passed through 90-100mph and watched the condictor dancing around for (maybe) over 30 seconds afterwards.
Scanning Garry Keenor's Overhead Line Electrification for Railways I can't see any figures for maximum allowed offset of the live parts, but it seemed to me that those oscillations would eat up a fair part of najaB's 500mm.
I would imagine that much of the benefit of insulated horns might be lost with conduction through any carbon contamination of their surface.
My umbrella experience was in the '70s. It was one of those early automatic types with nickel plated steel shaft and ribs. There was a faux leather handle cover, but the release button and the ferrule that secured the ribs when folded was too easy to touch.
The tingle wasn't much, a little more than the buzz that you get when touching some double insulated appliances. Touching it with a second digit didn't make any difference.
Clearly there was no leakage down to platform level, so I imagine that it was a capacitance effect as it wasnt there when the unbrella was dry.
Had I carried a multimeter I could have measured the current. Unfortunately, a meter of the day, - an Avo 8 was a bit heavy to carry in my brief case.
I can see how it would be. But it's worth keeping in mind that, while the induced voltages might be high, the current would be very low - so unless you have a pacemaker or similarly sensitive electronic medical device there's no real danger.
reddragon
Established Member
The OLE is AC and high voltage giving it the opportunity to arc or short to nearby objects. It also has the ability to induce current in parallel or nearby objects. The railway PTS rules states 2.75m as a safe MINIMUM distance. In dry weather you could get quite close to it in the right circumstances (note how small some bridge clearances are). In the wrong conditions, the wet, where poor earthing or bonding is in place things can be damn scary. I had contractors working on a bridge for me and the OLE was live but over 10m away. It was deemed safe but they touched the bridge and were thrown away, thankfully uninjured, just shocked. It turns out that the bonding was defective and earthing failed and the OLE was arcing all over the place out of sight!
DC has other issues. It leaks current like a sieve! Watch out for ballast in contact with it as a warning sign. It is quite 'safe' although not advised, to walk on the 3rd rail in rubber boots, as long as you don't step onto it or touch another rail. The danger is slipping, stepping on/off or worse touching another rail stepping on/off. You see lots of dead animals between the 3rd & running rails that have done this. Best avoid any contact with it and treat it with extreme caution. Where ballast is in contact with it, the return current is leaking out to earth, insulator pots are likely to be damaged and then you need to keep a bit clear of it, otherwise very close non contact is fine but NOT safe!
My advice? Don't take risks where the outcome is deadly. If you are happy to walk along a footpath without falling into the road, or beside a canal without falling in you should be fine beside a 3rd rail.
As other posters say, there are bigger dangers than the 3rd rail! Hit or Miss . . . say no more!
DC has other issues. It leaks current like a sieve! Watch out for ballast in contact with it as a warning sign. It is quite 'safe' although not advised, to walk on the 3rd rail in rubber boots, as long as you don't step onto it or touch another rail. The danger is slipping, stepping on/off or worse touching another rail stepping on/off. You see lots of dead animals between the 3rd & running rails that have done this. Best avoid any contact with it and treat it with extreme caution. Where ballast is in contact with it, the return current is leaking out to earth, insulator pots are likely to be damaged and then you need to keep a bit clear of it, otherwise very close non contact is fine but NOT safe!
My advice? Don't take risks where the outcome is deadly. If you are happy to walk along a footpath without falling into the road, or beside a canal without falling in you should be fine beside a 3rd rail.
As other posters say, there are bigger dangers than the 3rd rail! Hit or Miss . . . say no more!
Gloster
Established Member
Always treat the live rail as live. I was told there had been cases where PW staff would sit on the live rail when stopping for a meal break during possessions - it was at a nice height for sitting down - as they knew that the current was off (hook switches open, etc.) Which was fine until an electric or electro-diesel loco with the shoes down moved up and bridged the gap.
That's my view of it, it felt like the current from leakage inductance which is why it didn't bother me. However, I still think that it would need a longer conductor to run parallel to induce even a current that low (I would guess about 50-100µA) and it didn't seem to make any difference if there was a train drawing current in the area. The wet umbrella was acting as a large area conductive plate, so at a distance of say 1.5m, there would be a sizeable capacitance with a pretty high voltage gradient acoss the air between it and any live part of the OLE. I suppose I would have to try it under the cantilever arms/registration kit where there is more metalwork that would increase the effective area of the 25kV 'plate'.
It has occurred to me many times that, if I’m standing in a cab doorway looking back, my head is rather less than this distance away!
reddragon
Established Member
That's why all trains have an orange line at cant rail that you do not go above. Above that any electrics earth to the train & tracks or you if you go above it. Below it you are less electrically attractive than the train.
Pretty sure the top of my head is level with, or above, the cant rail if I’m standing in the doorway (I’m quite tall).
I might start stooping!
The train will still be more attractive than your head, unless you happen to have a metal plate in it.
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