3rd Rail Protection

[DownSouth]

Are there any restrictions for fan trips on third rail supply? Or does most all rollingstock in the UK clear the conductor rails. I would think some diesel units and possibly some steamers would cause headaches with clearance?

Robert

It's lower, at about the same height as the running rail, so there are pretty well no issues there. It's actually fairly likely that there would be other issues more likely to get in the way before that, like clearance at low bridges, platforms and so on.

Steam locos are more likely to cause interesting issues with overhead lines, due to the possibility of the exhaust making it easy for an arc to occur.

 

[Clip]

Are there any restrictions for fan trips on third rail supply? Or does most all rollingstock in the UK clear the conductor rails. I would think some diesel units and possibly some steamers would cause headaches with clearance?

Robert

Plenty of steam trips over the South East 3rd rail land.. Pretty much at least 1 or 2 a week during the summer..


Just to add that the only bottom contact 3rd rail system in the UK is the Docklands Light Railway which even though its bottom contact still has a nice plastic shroud over the top of the 3rd rail too.

 

[NightStar]

It's lower, at about the same height as the running rail, so there are pretty well no issues there. It's actually fairly likely that there would be other issues more likely to get in the way before that, like clearance at low bridges, platforms and so on.

Steam locos are more likely to cause interesting issues with overhead lines, due to the possibility of the exhaust making it easy for an arc to occur.

Interesting, Over here the conductor rail is slightly higher than the running rails. This tended to cause problems with a very select few locomotives with wide plows on the front.

The pressure of the steam exhaust could very possibly kink the wire on the overhead which is probably what causes the arcing.

Anyone have any other sites about UK conductor rail operations? I would love to see the size of the bonding diodes? They must be huge. I am fasinated by third rail systems and love to study up on them when given the chance. I also like Catenary systems as well.

Robert

 

[455driver]

The con rail IS higher than the running rails otherwise the collector shoes on the train would get knocked off at the first set of points (switches).

If a loco with snow ploughs is going to run on 3rd rail routes then the ploughs have to be locked in the high position.

 

[Clip]

Interesting, Over here the conductor rail is slightly higher than the running rails. This tended to cause problems with a very select few locomotives with wide plows on the front.

The pressure of the steam exhaust could very possibly kink the wire on the overhead which is probably what causes the arcing.

Anyone have any other sites about UK conductor rail operations? I would love to see the size of the bonding diodes? They must be huge. I am fasinated by third rail systems and love to study up on them when given the chance. I also like Catenary systems as well.

Robert

Robert

you could take a read of this website which has info about how it all came about and such like http://www.emus.co.uk/zone.htm

 

[NightStar]

The con rail is above the running rails here as well. But the con rail over here is higher than it is in the UK is the point I was trying to make. Our locomotives have fixed ploughs. So any loco that would not clear is banned from the 3rd rail lines.

Clip, thank you for the link. I will have a read.

Robert

 

[jopsuk]

Just to add that the only bottom contact 3rd rail system in the UK is the Docklands Light Railway which even though its bottom contact still has a nice plastic shroud over the top of the 3rd rail too.

The plastic shroud over the DLR conductor rail is pretty much the point of having the bottom-contact 3rd rail, as heavy snow isn't that common a problem in east London.

 

[Clip]

The plastic shroud over the DLR conductor rail is pretty much the point of having the bottom-contact 3rd rail, as heavy snow isn't that common a problem in east London.

Damn, I wonder what was in my garden the last few years then

 

[IanXC]

Are there any restrictions for fan trips on third rail supply? Or does most all rollingstock in the UK clear the conductor rails. I would think some diesel units and possibly some steamers would cause headaches with clearance?

Robert

I'm not 100% but as I understand it some caoching stock has clearance problems operating over third rail. When First Great Western divert their HSTs over third rail they have to reform them to only include SSL (short swing link bogies) mark 3 coaches rather than LSL (long swing link) ones.

 

[HSTEd]

I'm not 100% but as I understand it some caoching stock has clearance problems operating over third rail. When First Great Western divert their HSTs over third rail they have to reform them to only include SSL (short swing link bogies) mark 3 coaches rather than LSL (long swing link) ones.

I thought this was more a result of the Mark 3 having clearance issues due to clearances on the Southern region being rather tight than any specific problem with the third rail.

 

[topydre]

Interesting, Over here the conductor rail is slightly higher than the running rails. This tended to cause problems with a very select few locomotives with wide plows on the front.

The pressure of the steam exhaust could very possibly kink the wire on the overhead which is probably what causes the arcing.

Anyone have any other sites about UK conductor rail operations? I would love to see the size of the bonding diodes? They must be huge. I am fasinated by third rail systems and love to study up on them when given the chance. I also like Catenary systems as well.

Robert

This site is probably your best bet http://homepage.ntlworld.com/russelliott/3rd-4th.html
Also http://www.semgonline.com/home.html ; it has pretty much everything on the Southern Region third-rail operations, from the start to the present day; and some of the rolling stock pages have close-ups of the shoes and so on

 

[John55]

This site is probably your best bet http://homepage.ntlworld.com/russelliott/3rd-4th.html
Also http://www.semgonline.com/home.html ; it has pretty much everything on the Southern Region third-rail operations, from the start to the present day; and some of the rolling stock pages have close-ups of the shoes and so on

I don't know if you realise it but you have referred the OP back to the site he linked to in his original message.

This site http://homepage.ntlworld.com/russelliott/3rd-4th.html has lots of interesting stuff in but cannot be regarded as particularly accurate. The second sentence states " The Liverpool Overhead Railway was opened on 4 February 1893 and had an initial 4" square conductor rail operating at nominally 500V and set on porcelain insulators above and outside the running rails, with the ends of the conductor rail bent down to form ramps; it can thus be regarded as the precursor of the contemporary standard 3rd rail style."

This is incorrect as the LOR had a centre conductor until 1905/6 when it installed an outside conductor to allow interworking with the L&Y. Not a good start.

 

[topydre]

I don't know if you realise it but you have referred the OP back to the site he linked to in his original message.

This site http://homepage.ntlworld.com/russelliott/3rd-4th.html has lots of interesting stuff in but cannot be regarded as particularly accurate. The second sentence states " The Liverpool Overhead Railway was opened on 4 February 1893 and had an initial 4" square conductor rail operating at nominally 500V and set on porcelain insulators above and outside the running rails, with the ends of the conductor rail bent down to form ramps; it can thus be regarded as the precursor of the contemporary standard 3rd rail style."

This is incorrect as the LOR had a centre conductor until 1905/6 when it installed an outside conductor to allow interworking with the L&Y. Not a good start.

Ooops, sorry about that SEMGonline still has some good material though

 

[paul1609]

I thought this was more a result of the Mark 3 having clearance issues due to clearances on the Southern region being rather tight than any specific problem with the third rail.

No Ianxc is right, the suspension on LSL can in theory contact the third rail in certain failure modes.
Much of the Southern Routes are now otherwise open to 23 metre stock think class 442, 444, 171, 170, 158, 159 220 221
Most of the restrictions are now on the southeastern division

 

[Joseph_Locke]

I think what caused the fencing act in the 1860s was a major collision between a train and a hunt, when a Fox made its escape by crossing a line. The result killed a lot of hounds and derailed the train, although I don't think there were any Human casualties. It still made the national press, and the government had to be seen to be doing something - some things never change.

The Railways (Regulation) Acts of 1840 and 1842 prohibited trespass on the railway (1840) and required a fence to be provided continuously (1842) to prevent cattle straying onto the line and railwaymen rfom straying off it. This latter requirement is further amplified by the requirement of the Health and Safety at Work Act (1974) which places upon the railway a duty of care to trespassers who, after one or two test cases, are assumed to be illiterate and lacking any common sense.

Both these acts were superseded by the Railways Clauses Consolidation Act of 1845, which regularised the wording to save parliamentary time.

As an aside, the physical railway fence is often one yard inside the boundary, to allow it to be maintained from railway land on both sides.

 

[LE Greys]

The Railways (Regulation) Acts of 1840 and 1842 prohibited trespass on the railway (1840) and required a fence to be provided continuously (1842) to prevent cattle straying onto the line and railwaymen rfom straying off it. This latter requirement is further amplified by the requirement of the Health and Safety at Work Act (1974) which places upon the railway a duty of care to trespassers who, after one or two test cases, are assumed to be illiterate and lacking any common sense.

Both these acts were superseded by the Railways Clauses Consolidation Act of 1845, which regularised the wording to save parliamentary time.

As an aside, the physical railway fence is often one yard inside the boundary, to allow it to be maintained from railway land on both sides.

Thanks for clearing that up, I wasn't sure of the actual date.

 

[Old-School]

GidDay All, I have a nagging question? Why in the UK is the third rail left exposed as it is? What was the reason for not fitting the cover boards like we have here in the US? Was the issue cost? Or was it more along the lines of different safety standards being implemented? I would think in this day and age surely having the rails exposed like they are must create a lot of problems with those who cannot stay off the darn things?

Another reason the third rail is left exposed is also because Drivers who work on the third rail areas especially the old Southern Region area (not sure about third rail area such as places like Liverpool) are also trained in the the use of a short circuiting bar (A long wooden bar with a metal attachment, that is slid under and rests under the bottom of the third rail, then the wooden bar is lowered so the other end of the metal attachment sits on top of the running rail nearest the electric rail) in case of an emergency i:e fire on train, to isolate the electrical current by means of tripping a circuit breaker in the electrical control room, the Electrical Control Officer (ECO) will attempt to reset the circuit breaker three times, if after the third reset the breaker does not reset the the ECO knows there is a problem and will not attempt any further resets, He/She will the await for some form of communication from either Signaller or whoever caused the short circuit.

Certain parts of the third rail do have a form of sleeve attached to the bottom of it where the short circuit bar must not be used.

 

[D365]

I have a good photo in one of my books of a train being isolated on the Münich U-Bahn, albeit in black&white and with bottom-contact third rail like DLR.

 

[NightStar]

Another reason the third rail is left exposed is also because Drivers who work on the third rail areas especially the old Southern Region area (not sure about third rail area such as places like Liverpool) are also trained in the the use of a short circuiting bar (A long wooden bar with a metal attachment, that is slid under and rests under the bottom of the third rail, then the wooden bar is lowered so the other end of the metal attachment sits on top of the running rail nearest the electric rail) in case of an emergency i:e fire on train, to isolate the electrical current by means of tripping a circuit breaker in the electrical control room, the Electrical Control Officer (ECO) will attempt to reset the circuit breaker three times, if after the third reset the breaker does not reset the the ECO knows there is a problem and will not attempt any further resets, He/She will the await for some form of communication from either Signaller or whoever caused the short circuit.

Certain parts of the third rail do have a form of sleeve attached to the bottom of it where the short circuit bar must not be used.

Old School, Thank you for your interest in sharing. When the driver makes contact with the bottom of the live rail and then sits the wood bar on the running rail that must make one hell of a big bang? I would also think the arc and the noise would make he/she jump even know they are trained in the use of the bars? I don't think I would want to have to use one of those thank you very much.

Robert

 

[John55]

Old School, Thank you for your interest in sharing. When the driver makes contact with the bottom of the live rail and then sits the wood bar on the running rail that must make one hell of a big bang? I would also think the arc and the noise would make he/she jump even know they are trained in the use of the bars? I don't think I would want to have to use one of those thank you very much.

Robert

Arcing should not really be a problem when applying a short circuit. Arcing usually occurs when breaking a large current. If done correctly the application of the short circuiting bar should not create a bang and flash. If the circuit breakers do not trip and the short circuiting bar is removed while a short circuit current is flowing there will be all kinds of fun and games.

 

[KA4C]

There was a major problem when they electrified Hastings-Tonbridge with Badgers frying themselves by blundering into the rail, which could short out large sections. It got so bad that they removed sections that crossed traditional Badger paths, resulting in gaps.

Hmm, not quite true, when Tonbridge to Bo-Peep Jct was electrified, badger runs were surveyed and the "badger gaps" put in from the word go, Unfortunately the badgers, like some drivers, didn't bother reading their notices and continued to attempt to cross other than at their special gaps. This problem was dealt with by fitting green coloured "badger" shrouding under the con rail at the locations where the badgers actually crossed

 

[b0b]

Should also point out that the Chicago L system still uses exposed third rail and has at grade crossings.

This should give you a pretty good idea:

 

[Old-School]

Old School, Thank you for your interest in sharing. When the driver makes contact with the bottom of the live rail and then sits the wood bar on the running rail that must make one hell of a big bang? I would also think the arc and the noise would make he/she jump even know they are trained in the use of the bars? I don't think I would want to have to use one of those thank you very much.

Robert

Having had to use the short circuit bar in the past and also never knowing when I may have to use it again, I find it vital to remember 3 important rules I have given myself, which are (i) remember the training i received, (ii) always have a good solid safe stance when applying the bar and (iii) always look away from the bar and the rails its being used on when carrying out the final part of the procedure (the part that will actually cause the short circuit)

 

[NightStar]

To be honest I did not know the CTA had uncovered third rails. I learn something new everyday. I am more familiar with the UK third rail and that of the LIRR, NYC, PRR, NH. Subway lines never have been of much interest for me I am afraid. The London Underground intrigues me because of its 4 rail conductor system. Now I wonder if there are any 6 rail railways out there?

Old School. Those rules for applying the short bars sound good and solid to me. I guess the biggest thing one would have to be concerned with is having a steady hand and steady footing when working with one of those bars. Also not looking into the arc is a good idea as you mention.

Robert

 

[Matt Taylor]

Furthermore the short circuit bar cannot be used in areas where there is a fourth rail (East Putney for example), where there is laying snow, flooding, near hook switches or where there are yellow kick boards around the third rail.

 

[Monty]

Furthermore the short circuit bar cannot be used in areas where there is a fourth rail (East Putney for example), where there is laying snow, flooding, near hook switches or where there are yellow kick boards around the third rail.

Funny you mention that, at the training school in Basingstoke SWT are instructing the guards that the short cicuit bar can be used at East Putney or just outside Richmond. But yes as a general rule you cannot use short circuit bars on the LU 4th rail system.

 

[The Barlow Boy]

Another reason the third rail is left exposed is also because Drivers who work on the third rail areas especially the old Southern Region area (not sure about third rail area such as places like Liverpool) are also trained in the the use of a short circuiting bar (A long wooden bar with a metal attachment, that is slid under and rests under the bottom of the third rail, then the wooden bar is lowered so the other end of the metal attachment sits on top of the running rail nearest the electric rail) in case of an emergency i:e fire on train, to isolate the electrical current by means of tripping a circuit breaker in the electrical control room, the Electrical Control Officer (ECO) will attempt to reset the circuit breaker three times, if after the third reset the breaker does not reset the the ECO knows there is a problem and will not attempt any further resets, He/She will the await for some form of communication from either Signaller or whoever caused the short circuit.

Certain parts of the third rail do have a form of sleeve attached to the bottom of it where the short circuit bar must not be used.

You've not quite described that correctly. The bar should be slid over the running rail that's next to the conductor rail until the bar's contact tip is underneath but clear of the conductor rail with the shaped projection on the bar against the running rail then, turning to face away from the rails the handle of the bar should be pushed firmly down to make contact with the underneath of the conductor rail. Once contact has been made the bar should be left in place until the Electrical Control Room operator authorises it's removal - past experience has taught me that hitting it sideways with a lump hammer is often the only way.
In some locations the running rail is electrically isolated from the ground because of S&T requirements. At these locations (usually) yellow sleeving is attached as using a short circuiting bar may very well be futile - as well as wrecking S&T equipment!

 

[NightStar]

Ok. Now everyone has me intrigued as to what one of these bars looks like? Anyone have any photos?

Robert
--- old post above --- --- new post below ---
Ok this may seem like a silly question? However I am going to ask anyway. I understand the third rail runs at 750 volts DC with some rails being at 1200 volts DC. However I have never heard anyone give any suggestion as to the amperes coursing through the conductor rails? I know some diesel freight engines here in the US have 1800 Amps at full power to the traction motors. However I am under the impression the third rails are higher? More like 3000 amperes I thought I heard mentioned somewhere one time?

Robert

 

[455driver]

Funny you mention that, at the training school in Basingstoke SWT are instructing the guards that the short circuit bar can be used at East Putney or just outside Richmond. But yes as a general rule you cannot use short circuit bars on the LU 4th rail system.

We can use it on the East Putney- Wimbledon bit because the 3rd rail is at 660 volts and the 4th rail at zero volts, so isolating the 3rd rail will cut the power completely.
On the proper underground sections the 3rd rail is at plus 440 volts and the 4th rail is at minus 220 volts, so if you used our SC bar you would have the 4th rail still with a potential voltage in it.

 

[Monty]

We can use it on the East Putney- Wimbledon bit because the 3rd rail is at 660 volts and the 4th rail at zero volts, so isolating the 3rd rail will cut the power completely.
On the proper underground sections the 3rd rail is at plus 440 volts and the 4th rail is at minus 220 volts, so if you used our SC bar you would have the 4th rail still with a potential voltage in it.

Ah thanks for clearing that up, they did not make it clear to us that the middle rail on that section was set to 0 volts.