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Shielding 750 volt 3rd rail ?
It has always seemed to me that the 750 volt 3rd rail is a bad
idea. Rather it is the idea that somebody (Sprague?) first thought of and it got made permanent. Its drawbacks in its present form seem to me to be :- * The possibility of electrocuting somebody. Are there many casualties? More difficult to answer; how much do the procedures to avoid electrocution cost in direct and indirect costs? * It too often gets covered with ice in winter (and wet leaves in autumn?) * The danger of electrocution means that voltages cannot be raised to increase power delivery. Italian state railways (FS = Ferrovia della Stato) started with 3000 volt overhead wires, but everything has now been done so that they can increase the voltage to 6000 volts, so doubling the power that can be delivered. So I have been thinking of the possibilities of shielding the 3rd rail. The shield would be made of springy plastic, with square holes moulded in the bottom, to allow rainwater and leaves to drop out of the bottom and cooling air to rise through them. The holes would be too small to allow a hand to be put through and too far for a finger to reach the 3rd rail. The shield would be fitted by springing open the shield, and pushing it upwards over the bottom of the 3rd rail. A cut will have to be made on the train side at each insulator to fit the shield, and some of the bottom grille cut away to allow it to be put over the insulator. Keys projecting into the inner space will be clipped to the lower web of the rail, thus allowing air to flow round the 3rd rail. This requires plastic which will keep its spring for many years, and this might be a problem. Along the side of the top there is a slot which the train pick-up shoe (more like a "tongue") goes through. It is under an overhang to stop rain and leaves from getting in, but being at the top it creates some chimney effect for cooling the 3rd rail. The slot at the top would be too narrow and too far from the 3rd rail to put hand or finger onto it. Suicide will still be possible for somebody who wants to do it, but somebody who is on a railway track and wants to commit suicide has plenty of other ways of bringing it all to an end. An ACCIDENT is now very difficult. To complete this would obviously be a 10 or 20 year project, (even longer to replace some of the longer-lived stock with higher voltage stock) but some of the benefits, such as no icing in winter, would come immediately. To get everything lined up it obviously also requires a standard of track laying better than some we have seen in recent years. Is that good or bad? There are shielded 3rd rails on the continent, but I'm afraid I can't see Network Rail, with its many problems, and its difficulties with the TOCs, undertaking a project like this, no matter how worthwhile. Michael Bell ________________________________________ | ___________________________________ | | | | | | | ||||||||||||||||||||||||||||| | | | | || ____ _______________ | | |__| || | | | | | | || | | |_ _| | | ||||||||||||||||||||| | | | 3rd | | | | | | rail | | | Pick-up tongue | | | | | | | | | | | | | | | | | | | | | | / | | \ / \ / | | \ / \ / | | // \ | | /____________________\ | Shield | __\ /___ | clipped | | | | to lower | | | | web of | | | | rail | |___________________________| | |_______________________________| Plastic grille at bottom. |
Shielding 750 volt 3rd rail ?
Michael Bell wrote:
It has always seemed to me that the 750 volt 3rd rail is a bad idea. snip So I have been thinking of the possibilities of shielding the 3rd rail. snip Other people have designed such systems too. There is one already in operation in London - the DLR. To complete this would obviously be a 10 or 20 year project, (even longer to replace some of the longer-lived stock with higher voltage stock) but some of the benefits, such as no icing in winter, would come immediately. Your design includes a plastic cover over the top of the rail. Doesn't this prevent existing stock from using rails fitted with your plastic covers? I don't understand how you intend to operate during the 10-20 year conversion period. Also, have you done any sort of cost-benefit analysis for this project? -- Richard J. (to e-mail me, swap uk and yon in address) |
Shielding 750 volt 3rd rail ?
Michael Bell writes
There are shielded 3rd rails on the continent, but I'm afraid I can't see Network Rail, with its many problems, and its difficulties with the TOCs, undertaking a project like this, no matter how worthwhile. Protected third rail is used on the DLR. HSE would not allow any new rail system to use unprotected third rail - although they will allow extensions to existing systems. From 1916 until around 1990, the Manchester Victoria-Bury service used trains operating off a 1200V DC protected third rail - with a side-contact. This system was replaced by overhead wires when the route was converted for use as part of the Metrolink system. A couple of pics which may help to illustrate the Bury system; http://www.therailwaycentre.com/EMU%...le/504_asbuilt http://easyweb.easynet.co.uk/~gsgleaves/gauge.jpg -- Dave |
Shielding 750 volt 3rd rail ?
In article , Richard J.
wrote: Michael Bell wrote: It has always seemed to me that the 750 volt 3rd rail is a bad idea. snip So I have been thinking of the possibilities of shielding the 3rd rail. snip Other people have designed such systems too. There is one already in operation in London - the DLR. To complete this would obviously be a 10 or 20 year project, (even longer to replace some of the longer-lived stock with higher voltage stock) but some of the benefits, such as no icing in winter, would come immediately. Your design includes a plastic cover over the top of the rail. Doesn't this prevent existing stock from using rails fitted with your plastic covers? I don't understand how you intend to operate during the 10-20 year conversion period. Obviously the fleet has to be modified first. That's the smallest part of the job! Also, have you done any sort of cost-benefit analysis for this project? No, I have done no cost-benefit analyis. But if DLR (which I should have thought of) have done it, and foreign systems have done it, then they must have made some sort of calculation. -- Michael |
Shielding 750 volt 3rd rail ?
On Fri, 8 Aug 2003 23:43:59 +0100, Michael Bell
wrote: It has always seemed to me that the 750 volt 3rd rail is a bad idea. Rather it is the idea that somebody (Sprague?) first thought of and it got made permanent. Its drawbacks in its present form seem to me to be :- * The possibility of electrocuting somebody. Are there many casualties? More difficult to answer; how much do the procedures to avoid electrocution cost in direct and indirect costs? There aren't as many electrocutions as you may think there is. In fact there are less deaths on Third Rail Electrifaction areas than there are on Overhead Lines which has a even more dangerous 25kV. * It too often gets covered with ice in winter (and wet leaves in autumn?) Leaves in the autumn are not a problem with third rail. And deicing trains are used with great effect on the third rail. The only time icing of the third rail becomes a problem is because Network Rail Controllers fail to predict a heavy frost/ snow fall. * The danger of electrocution means that voltages cannot be raised to increase power delivery. Italian state railways (FS = Ferrovia della Stato) started with 3000 volt overhead wires, but everything has now been done so that they can increase the voltage to 6000 volts, so doubling the power that can be delivered. Increase in volt to 1000 volts DC was muted some years ago, instead more intermediate Traction Parallel Huts where built. So I have been thinking of the possibilities of shielding the 3rd rail. The shield would be made of springy plastic, with square holes moulded in the bottom, to allow rainwater and leaves to drop out of the bottom and cooling air to rise through them. The holes would be too small to allow a hand to be put through and too far for a finger to reach the 3rd rail. Again leaves aren't a problem as is rain water. The DLR have a a bottom contact third rail which is covered. the Manchester to Bury line, now part of the Manchester Tram link, used to have a side contact third rail that was covered and this was 1500 volts dc. If a risk assessment was done of the Third Rail system, covering wouldn't be cost productive as electropcution by third rail is exceptionally low. As no one except authorised personell should be on the line, one's trained in third rail areas, no one should be putting fingers any where near it. Trepassers have more than adequate warning of the presence of the third rail. And anyone strayiong on the line, knw they shouldn't be there and deserve to be hurt if they are. The shield would be fitted by springing open the shield, and pushing it upwards over the bottom of the 3rd rail. A cut will have to be made on the train side at each insulator to fit the shield, and some of the bottom grille cut away to allow it to be put over the insulator. Keys projecting into the inner space will be clipped to the lower web of the rail, thus allowing air to flow round the 3rd rail. This requires plastic which will keep its spring for many years, and this might be a problem. Air around the conductor rail???? Plastic against the conductor rail will not cause it to heat up. Along the side of the top there is a slot which the train pick-up shoe (more like a "tongue") goes through. It is under an overhang to stop rain and leaves from getting in, but being at the top it creates some chimney effect for cooling the 3rd rail. You're obsessed with leaves. The tolerances of the shoe running on the thrid rail head are such that there would be a large gap for you to put your fingers in!!!!!!! Not all train shoes are the same, different units have different types, sizes and shapes. The slot at the top would be too narrow and too far from the 3rd rail to put hand or finger onto it. Suicide will still be possible for somebody who wants to do it, but somebody who is on a railway track and wants to commit suicide has plenty of other ways of bringing it all to an end. An ACCIDENT is now very difficult. Funny enough, suicides don't commit sucide with the third rail, never heard of any cases of this. They tend to jump in front of those big iron things called trains. Perhaps you would like the exterior of these padded with cotton wool to lessen the impact of suicide attempts!!!!!!!!! To complete this would obviously be a 10 or 20 year project, (even longer to replace some of the longer-lived stock with higher voltage stock) but some of the benefits, such as no icing in winter, would come immediately. To get everything lined up it obviously also requires a standard of track laying better than some we have seen in recent years. Is that good or bad? Are you insane. Trains can run up to 100mph on thrid rail systems, and possibly higher, even with just 750 volts dc. The benefits of a covered third rail are nil compared to the cost involved in covering it!!! And what has better standards of track laying got to do with it. There are shielded 3rd rails on the continent, but I'm afraid I can't see Network Rail, with its many problems, and its difficulties with the TOCs, undertaking a project like this, no matter how worthwhile. The only problems Network Rail have got is the British Government continually interfering with the attempts of honest dedicated railwaymen trying to give the public a train service. C Life without sex just isn't life. Make love not war! |
Shielding 750 volt 3rd rail ?
"Christine" wrote in message ... On Fri, 8 Aug 2003 23:43:59 +0100, Michael Bell wrote: It has always seemed to me that the 750 volt 3rd rail is a bad idea. Rather it is the idea that somebody (Sprague?) first thought of and it got made permanent. Its drawbacks in its present form seem to me to be :- * The possibility of electrocuting somebody. Are there many casualties? More difficult to answer; how much do the procedures to avoid electrocution cost in direct and indirect costs? There aren't as many electrocutions as you may think there is. In fact there are less deaths on Third Rail Electrifaction areas than there are on Overhead Lines which has a even more dangerous 25kV. A track worker was killed just this week (one of the reasons for the '9 hour Southampton to London' fiasco widely reported). * It too often gets covered with ice in winter (and wet leaves in autumn?) Leaves in the autumn are not a problem with third rail. And deicing trains are used with great effect on the third rail. The only time icing of the third rail becomes a problem is because Network Rail Controllers fail to predict a heavy frost/ snow fall. * The danger of electrocution means that voltages cannot be raised to increase power delivery. Italian state railways (FS = Ferrovia della Stato) started with 3000 volt overhead wires, but everything has now been done so that they can increase the voltage to 6000 volts, so doubling the power that can be delivered. Increase in volt to 1000 volts DC was muted some years ago, instead more intermediate Traction Parallel Huts where built. So I have been thinking of the possibilities of shielding the 3rd rail. The shield would be made of springy plastic, with square holes moulded in the bottom, to allow rainwater and leaves to drop out of the bottom and cooling air to rise through them. The holes would be too small to allow a hand to be put through and too far for a finger to reach the 3rd rail. Again leaves aren't a problem as is rain water. The DLR have a a bottom contact third rail which is covered. the Manchester to Bury line, now part of the Manchester Tram link, used to have a side contact third rail that was covered and this was 1500 volts dc. If a risk assessment was done of the Third Rail system, covering wouldn't be cost productive as electropcution by third rail is exceptionally low. As no one except authorised personell should be on the line, one's trained in third rail areas, no one should be putting fingers any where near it. Trepassers have more than adequate warning of the presence of the third rail. And anyone strayiong on the line, knw they shouldn't be there and deserve to be hurt if they are. So, small children (who, for whatever reason, may not have been told about the dangers of going near the railway), or persons who accidentally fall of a platform 'deserve to be hurt'. That is rather harsh! The shield would be fitted by springing open the shield, and pushing it upwards over the bottom of the 3rd rail. A cut will have to be made on the train side at each insulator to fit the shield, and some of the bottom grille cut away to allow it to be put over the insulator. Keys projecting into the inner space will be clipped to the lower web of the rail, thus allowing air to flow round the 3rd rail. This requires plastic which will keep its spring for many years, and this might be a problem. Air around the conductor rail???? Plastic against the conductor rail will not cause it to heat up. Along the side of the top there is a slot which the train pick-up shoe (more like a "tongue") goes through. It is under an overhang to stop rain and leaves from getting in, but being at the top it creates some chimney effect for cooling the 3rd rail. You're obsessed with leaves. The tolerances of the shoe running on the thrid rail head are such that there would be a large gap for you to put your fingers in!!!!!!! Not all train shoes are the same, different units have different types, sizes and shapes. The slot at the top would be too narrow and too far from the 3rd rail to put hand or finger onto it. Suicide will still be possible for somebody who wants to do it, but somebody who is on a railway track and wants to commit suicide has plenty of other ways of bringing it all to an end. An ACCIDENT is now very difficult. Funny enough, suicides don't commit sucide with the third rail, never heard of any cases of this. They tend to jump in front of those big iron things called trains. Perhaps you would like the exterior of these padded with cotton wool to lessen the impact of suicide attempts!!!!!!!!! To complete this would obviously be a 10 or 20 year project, (even longer to replace some of the longer-lived stock with higher voltage stock) but some of the benefits, such as no icing in winter, would come immediately. To get everything lined up it obviously also requires a standard of track laying better than some we have seen in recent years. Is that good or bad? Are you insane. Trains can run up to 100mph on thrid rail systems, and possibly higher, even with just 750 volts dc. The benefits of a covered third rail are nil compared to the cost involved in covering it!!! And what has better standards of track laying got to do with it. The third rail system is an example of a historical solution that, if we were starting from scratch, we would not dream of using nowadays. However, because it is so extensive the cost of modifying or replacing it outweighs the resulting safety benefit. There are shielded 3rd rails on the continent, but I'm afraid I can't see Network Rail, with its many problems, and its difficulties with the TOCs, undertaking a project like this, no matter how worthwhile. The only problems Network Rail have got is the British Government continually interfering with the attempts of honest dedicated railwaymen trying to give the public a train service. I really don't think you can blame the Government for all of the railways woes (although their attempts to try and 'make things better' have often done more harm than good). C Life without sex just isn't life. Make love not war! |
Shielding 750 volt 3rd rail ?
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Shielding 750 volt 3rd rail ?
Michael Bell wrote in message ...
It has always seemed to me that the 750 volt 3rd rail is a bad idea. Rather it is the idea that somebody (Sprague?) first thought of and it got made permanent. Its drawbacks in its present form seem to me to be :- * The possibility of electrocuting somebody. Are there many casualties? More difficult to answer; how much do the procedures to avoid electrocution cost in direct and indirect costs? * It too often gets covered with ice in winter (and wet leaves in autumn?) So does the Overhead Line....... * The danger of electrocution means that voltages cannot be raised to increase power delivery. Italian state railways (FS = Ferrovia della Stato) started with 3000 volt overhead wires, but everything has now been done so that they can increase the voltage to 6000 volts, so doubling the power that can be delivered. Well how many people do you know that get up in the morning and take the dog for a walk down the third rail? I know some idiots do it but the majority don't! So I have been thinking of the possibilities of shielding the 3rd rail. The shield would be made of springy plastic, with square holes moulded in the bottom, to allow rainwater and leaves to drop out of the bottom and cooling air to rise through them. The holes would be too small to allow a hand to be put through and too far for a finger to reach the 3rd rail. And whos going to pay for this? To be honest I'm supprised your not complaining at overhead powerlines, street cables etc. Someone could easily kill themselves by sticking a knitting needle into a plug socket and turning it on, and many places have high voltage sockets for cleaning equipment. Are you one of these doughnuts who is trying to dieselise the country? |
Shielding 750 volt 3rd rail ?
"Acrosticus" wrote in message ... From: Michael Bell Date: 08/08/2003 23:43 GMT Daylight Time It has always seemed to me that the 750 volt 3rd rail is a bad idea. Too right! Massive amperages, high resistances, huge numbers of substations in relation to the length of a line. It's an idea that's really past its sell by date. If you want to electrify, do it properly with 25Kv at 50 Hertz in a wire up on some sticks. Tinkering about with 750v DC is about as much good as rearranging the deckchairs on the deck of the "Titanic". And as soon as we get some windy weather all the overhead lines come down and the entire rail network is screwed. |
Shielding 750 volt 3rd rail ?
The Equalizer wrote:
"Acrosticus" wrote in message ... From: Michael Bell Date: 08/08/2003 23:43 GMT Daylight Time It has always seemed to me that the 750 volt 3rd rail is a bad idea. Too right! Massive amperages, high resistances, huge numbers of substations in relation to the length of a line. It's an idea that's really past its sell by date. If you want to electrify, do it properly with 25Kv at 50 Hertz in a wire up on some sticks. Tinkering about with 750v DC is about as much good as rearranging the deckchairs on the deck of the "Titanic". And as soon as we get some windy weather all the overhead lines come down and the entire rail network is screwed. Not all, just that which was put up on the cheap. |
Shielding 750 volt 3rd rail ?
"Cast_Iron" wrote in message ... The Equalizer wrote: "Acrosticus" wrote in message ... From: Michael Bell Date: 08/08/2003 23:43 GMT Daylight Time It has always seemed to me that the 750 volt 3rd rail is a bad idea. Too right! Massive amperages, high resistances, huge numbers of substations in relation to the length of a line. It's an idea that's really past its sell by date. If you want to electrify, do it properly with 25Kv at 50 Hertz in a wire up on some sticks. Tinkering about with 750v DC is about as much good as rearranging the deckchairs on the deck of the "Titanic". And as soon as we get some windy weather all the overhead lines come down and the entire rail network is screwed. Not all, just that which was put up on the cheap. Network Rail = Cheap |
Shielding 750 volt 3rd rail ?
On Fri, 8 Aug 2003 23:43:59 +0100, Michael Bell
wrote in : * The danger of electrocution means that voltages cannot be raised to increase power delivery. Italian state railways (FS = Ferrovia della Stato) started with 3000 volt overhead wires, but everything has now been done so that they can increase the voltage to 6000 volts, so doubling the power that can be delivered. Redo your maths; V*2 = P*4, modulo foibles of inductive loads. -- Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration, Brunel University. Room 40-1-B12, CERN KotPT -- "for stupidity above and beyond the call of duty". |
Shielding 750 volt 3rd rail ?
Michael Bell wrote:
In article , Richard J. wrote: Michael Bell wrote: It has always seemed to me that the 750 volt 3rd rail is a bad idea. snip So I have been thinking of the possibilities of shielding the 3rd rail. snip Other people have designed such systems too. There is one already in operation in London - the DLR. To complete this would obviously be a 10 or 20 year project, (even longer to replace some of the longer-lived stock with higher voltage stock) but some of the benefits, such as no icing in winter, would come immediately. Your design includes a plastic cover over the top of the rail. Doesn't this prevent existing stock from using rails fitted with your plastic covers? I don't understand how you intend to operate during the 10-20 year conversion period. Obviously the fleet has to be modified first. That's the smallest part of the job! Ah, so the fleet is modified in such a way that it can use both the old and the new design of rail. Not exactly a trivial task. Also, have you done any sort of cost-benefit analysis for this project? No, I have done no cost-benefit analyis. So you have proposed an expensive project for safety reasons which HSE don't consider mandatory, with no analysis of whether it's worth spending the money. I think you need to justify it better than that. But if DLR (which I should have thought of) have done it, and foreign systems have done it, then they must have made some sort of calculation. DLR did it AFAIK because by then it was mandatory for new systems. The fact that HSE did not mandate changing existing networks suggests that this would not produce a reasonable cost-benefit. -- Richard J. (to e-mail me, swap uk and yon in address) |
Shielding 750 volt 3rd rail ?
In article , Dr Ivan D. Reid
wrote: On Fri, 8 Aug 2003 23:43:59 +0100, Michael Bell wrote in : * The danger of electrocution means that voltages cannot be raised to increase power delivery. Italian state railways (FS = Ferrovia della Stato) started with 3000 volt overhead wires, but everything has now been done so that they can increase the voltage to 6000 volts, so doubling the power that can be delivered. Redo your maths; V*2 = P*4, modulo foibles of inductive loads. I don't see that. Current can't be increased because it is limited by the crosssection of the overhead wire, at least not without it overheating, sagging and other undesireable behaviour. But if you double the voltage at the same current, you double the power. At least that's my thinking. -- Michael Bell |
Shielding 750 volt 3rd rail ?
Dave wrote in message ...
The live rail is always furthest from the platform. It would have to be a spectacular fall in order to land on the live rail. Usually, but not always. Where there is a platform on both sides of the track one of them has to be on the same side as the conductor rail. Norwood Junction sprigs to mind, and I think this situation also existed at Ryde Pier Head when it was first electrified. I can also think of a case where there was, until recently, a conductor rail on the platform side when there was a platform on only one Side. This was at London Bridge, where the conductor rail had to be on the platform side for a short distance because of a crossover which I believe was used to allow the locomotive of a mail train to run around. It was disused for some years before removal. I suspect that the same situation also existed in other places. Generally, I think the third rail system is acceptably safe, but I don't like conductor rails below platform edges. |
Shielding 750 volt 3rd rail ?
Stephen Furley writes
The live rail is always furthest from the platform. It would have to be a spectacular fall in order to land on the live rail. Usually, but not always. Where there is a platform on both sides of the track one of them has to be on the same side as the conductor rail. And in the few places where this is the case, you'll usually find the live rail is protected with wooden boards. -- Dave |
Shielding 750 volt 3rd rail ?
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Shielding 750 volt 3rd rail ?
"Acrosticus" wrote in message
... From: Michael Bell Date: 09/08/2003 22:28 GMT Daylight Time Current can't be increased because it is limited by the crosssection of the overhead wire, at least not without it overheating, sagging and other undesireable behaviour. Unless you install wire with a greater cross sectional area of course, which is more difficult to keep up in the air because it'll be heavier, so I think you're right there. But if you double the voltage at the same current, you double the power. At least that's my thinking. And you seem to be right here two. Since volts x amps = watts, double the voltage whilst keeping the amperage the same and you've doubled the power too. Don't forget loaded voltage drop - that is often a major limitation in the design length of a power feeder, not the absolute current carrying capacity of cable or rail. When the train is drawing power at the far end of a section, with higher voltage but with the same old feeder spacing, more current might be passed by the same conductor without voltage dropping by so much as a proportion of the feed. -- Mark |
Shielding 750 volt 3rd rail ?
"The Equalizer" wrote in message ... "Cast_Iron" wrote in message ... The Equalizer wrote: "Acrosticus" wrote in message ... From: Michael Bell Date: 08/08/2003 23:43 GMT Daylight Time It has always seemed to me that the 750 volt 3rd rail is a bad idea. Too right! Massive amperages, high resistances, huge numbers of substations in relation to the length of a line. It's an idea that's really past its sell by date. If you want to electrify, do it properly with 25Kv at 50 Hertz in a wire up on some sticks. Tinkering about with 750v DC is about as much good as rearranging the deckchairs on the deck of the "Titanic". And as soon as we get some windy weather all the overhead lines come down and the entire rail network is screwed. Not all, just that which was put up on the cheap. Network Rail = Cheap Network Rail = Expensive Railtrack = Less Expensive British Rail = Cheap |
Shielding 750 volt 3rd rail ?
Matthew Malthouse writes
Railtrack, seriously underinvesting, starved of money by the government. Surely that should be; Railtrack, seriously underinvesting, too busy paying dividends to shareholder and bonuses to directors. -- Dave |
Shielding 750 volt 3rd rail ?
In article , Matthew
Malthouse writes British Rail, very seriously underinvesting, Nowhere near true. Read Roger Ford's column in the current (August) Modern Railways. -- Clive D.W. Feather, writing for himself | Home: Tel: +44 20 8371 1138 (work) | Web: http://www.davros.org Fax: +44 870 051 9937 | Work: Written on my laptop; please observe the Reply-To address |
Shielding 750 volt 3rd rail ?
On Mon, 11 Aug 2003 13:06:42 +0100 Dave wrote:
} Matthew Malthouse writes } Railtrack, seriously underinvesting, starved of money by the } government. } } Surely that should be; } } Railtrack, seriously underinvesting, too busy paying dividends to } shareholder and bonuses to directors. That too. But it comes to the same thing in the end. Matthew -- Il est important d'être un homme ou une femme en colère; le jour où nous quitte la colère, ou le désir, c'est cuit. - Barbara http://www.calmeilles.co.uk/ |
Shielding 750 volt 3rd rail ?
Mid voltage AC would probably have many attractions. Suggest 625/1250/2500
respectively for underground, inner urban and open country respectively. Dual voltage with 25kV relatively easy to do. DW "Cast_Iron" wrote in message ... : Boltar wrote: : are (Acrosticus) wrote in message : ... : From: Michael Bell : Date: 08/08/2003 23:43 GMT Daylight Time : : It has always seemed to me that the 750 volt 3rd rail is : a bad : idea. : : Too right! Massive amperages, high resistances, huge : numbers of substations in : relation to the length of a line. It's an idea that's : really past its sell by : date. If you want to electrify, do it properly with 25Kv : at 50 Hertz in a wire : up on some sticks. Tinkering about with 750v DC is about : as much good as : rearranging the deckchairs on the deck of the "Titanic". : : OTOH hand , when was the last time that you heard of trains : being stuck or : cancelled because the 3rd rail fell over? There doesn't : seem to be a winter : that goes by without some AC line being screwed by snapped : overhead wires. : Catenary is fragile and flakey and is a terrible design : plus it looks bloody : awful too. The only place its really needed is street based : tramways. : : What is needed is some sort of mid voltage (maybe : 3000-6000V) sturdy ground : based 3rd rail system which isn't as fragile as overhead : wires but doesn't : have the power losses of standard 750V 3rd rail. I'm sure : isn't beyond the wit : of man to devise it. : : Probably incredibly easy to devise, but paying for it - now that's the : difficult one to organise. : : |
Shielding 750 volt 3rd rail ?
On Mon, 11 Aug 2003 12:14:16 +0100, Christine
wrote: If a track worker got electrocuted, why wasn't he complying to Railway Safety Standards. I heard that he slipped or stumbled onto the rail If he was he would not have been electrocuted, no matter how harsh it sounds. There are Railway Safety Standards for personell who work alongside Third Rail Electrifaction, and if these are stuck to rigidly to the letter, then no one would get hurt! Doe they prevent people from slipping or stumbling? |
Shielding 750 volt 3rd rail ?
Matthew Malthouse wrote in message ...
On Mon, 11 Aug 2003 13:06:42 +0100 Dave wrote: } Matthew Malthouse writes } Railtrack, seriously underinvesting, starved of money by the } government. } } Surely that should be; } } Railtrack, seriously underinvesting, too busy paying dividends to } shareholder and bonuses to directors. That too. But it comes to the same thing in the end. Matthew To be totally honest, whatever happens you're always going to find a problem! It seems that a lot of people enjoy criticising this railway in which tries to please all, something that either of you two could not do. On the subject of conductor rail on the same side of platforms, its no different really to people climbing on station roofs and coming into contact with the OHLE, and yes it can easily be done! Then again I ask how many of you are planning a nice stroll down the Brighton mainline this weekend? Contact with the third rail is near enough impossible if one is not being totally stupid, i.e strolling off crossings (even then through a cattle grid) onto the line. It's a ridiculous argument, and yes if a line was to be installed from new, unless it is within the Southern Electrified region, and mainly due to stock compataibility, the line is more likely to be Over-head line equipment. Any other ridiculous ideas? |
Shielding 750 volt 3rd rail ?
] (Arthur Figgis) wrote in message ...
That says more about particular implementations than anything intrinsic to overhead lines. The ECML wires were put up very cheaply, as the only way the treasury would allow it to be electrified at all, and so fall over. The WCML ones are much better built, and don't tend to fall over. They might not fall over on their own but if something hits them or falls on them its a pretty major task to reinstate them. If a 3rd rail gets damaged its a far simpler job to fix. plus it looks bloody awful too. The only place its really needed is street based tramways. High speed lines? Thats only because currently (no pun intended) high speed lines use overhead because they use high voltage, they're not intrinsically required like they are on a tramway (to keep the electricity well out of the way of people and vehicles). If a high power 3rd rail design could be devised (which I'm sure would look substaintially different to "traditional" 3rd rail) then there is no reason they couldn't use that and perhaps it might have avoided the problem that the Eurostar had last year where freezing sea spray got onto the overhead lines and stopped all the trains. B2003 |
Shielding 750 volt 3rd rail ?
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Shielding 750 volt 3rd rail ?
In article ,
Boltar wrote: OTOH hand , when was the last time that you heard of trains being stuck or cancelled because the 3rd rail fell over? Sometime around last year, around Bank. I can't remember the details, but I think the central conductor rail "fell over", rather than the outer one. (OK: so it was trains being stuck/delayed/canceled because the 4th rail fell over, rather then the 3rd. And it was a rather unusual incident.) -- Good night little fishey-wishes.... I've counted you, so no sneaky eating each other. -- FW (should I worry?) |
Shielding 750 volt 3rd rail ?
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Shielding 750 volt 3rd rail ?
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Shielding 750 volt 3rd rail ?
On the subject of conductor rail on the same side of platforms, its no
different really to people climbing on station roofs and coming into contact with the OHLE, except people shouldn't be climbing on the roof (by people I'm assuming you mean passengers, correct me if I'm wrong). People shouldn't be trespassing on railway lines, but passengers do have a legitimate reason to be on platforms, and can accidentally slip, be pushed/bumped into etc, and fall onto the track. I have actually seen this happen once, although thankfully at a non electrified location without any trains in the area. Andrew |
Shielding 750 volt 3rd rail ?
] (Arthur Figgis) wrote in message ...
Why re-invent the wheel, and introduce an incompatible new system at huge expense? Internationally 25kV 50 Hz is effectively standard nowadays, the equipment is available off the shelf (and once we shoot all the Daily Mail readers, sorry, I mean sort out the important political issues, we might even be able to get standard foreign trains running through to Britain on it). They'll only be able to run on the CTRL, they'd be too big for other lines. I can't understand why we have such a restricted loading gauge in this country, I mean we had broad gauge on the GWR for heavens sake, surely the loading gauge of that line if nothing else must have been built big enough for european trains? B2003 |
Shielding 750 volt 3rd rail ?
Boltar wrote:
] (Arthur Figgis) wrote in message ... Why re-invent the wheel, and introduce an incompatible new system at huge expense? Internationally 25kV 50 Hz is effectively standard nowadays, the equipment is available off the shelf (and once we shoot all the Daily Mail readers, sorry, I mean sort out the important political issues, we might even be able to get standard foreign trains running through to Britain on it). They'll only be able to run on the CTRL, they'd be too big for other lines. I can't understand why we have such a restricted loading gauge in this country, I mean we had broad gauge on the GWR for heavens sake, surely the loading gauge of that line if nothing else must have been built big enough for european trains? Perhaps the height restriction is less? Also, when the main line through Ealing and Southall was quadrupled in the 1870's, the new tracks were standard gauge only. I guess that many changes to layouts since then have eliminated any capability of running wider trains. -- Richard J. (to e-mail me, swap uk and yon in address) |
Shielding 750 volt 3rd rail ?
"Mike Bristow" wrote in message ... In article , Boltar wrote: OTOH hand , when was the last time that you heard of trains being stuck or cancelled because the 3rd rail fell over? Sometime around last year, around Bank. I can't remember the details, but I think the central conductor rail "fell over", rather than the outer one. (OK: so it was trains being stuck/delayed/canceled because the 4th rail fell over, rather then the 3rd. And it was a rather unusual incident.) Happened to the pozzie at Wood Green about 7 years ago, IIRC the LUL jargon for such an incident is "Turned Juice Rail" -- Cheers, Steve. If The Good Lord had meant for us to be fiscally prudent, He would not have given us the platinum credit card... Change colour to PC Plod's lights to reply. |
Shielding 750 volt 3rd rail ?
In message , Arthur Figgis
] writes FWIW, you don't have to have overhead lines for electric trams - London had its conduit, and various places have had stud contact, including parts of the brand new tramway in Bordeaux. In fairness though, The Bordeaux system isn't open yet and the stud contact hasn't been proved to work successfully. -- Steve Fitzgerald has now left the building. You will find him in London's Docklands, E16, UK (please use the reply to address for email) |
Shielding 750 volt 3rd rail ?
In article , Matthew
Malthouse writes } British Rail, very seriously underinvesting, } Nowhere near true. } Read Roger Ford's column in the current (August) Modern Railways. The gist? A detailed analysis of this canard. Basically, BR invested lots. The perception as long as I can remember has been that railways have suffered from lack of funds. Yes, as in there's a lot of improvements that could have been done with more money. But, unlike Railtrack, BR at least invested enough to keep the network stable. -- Clive D.W. Feather, writing for himself | Home: Tel: +44 20 8371 1138 (work) | Web: http://www.davros.org Fax: +44 870 051 9937 | Work: Written on my laptop; please observe the Reply-To address |
Shielding 750 volt 3rd rail ?
In article , Mike Bristow
writes OTOH hand , when was the last time that you heard of trains being stuck or cancelled because the 3rd rail fell over? Sometime around last year, around Bank. I can't remember the details, but I think the central conductor rail "fell over", rather than the outer one. I've seen various reports at various times along the lines of "65 positive shoes found just outside X station because of a displaced current rail". You even get the really nasty case where the displaced rail displaces a shoe, which then displaces another piece of current rail elsewhere, which .... -- Clive D.W. Feather, writing for himself | Home: Tel: +44 20 8371 1138 (work) | Web: http://www.davros.org Fax: +44 870 051 9937 | Work: Written on my laptop; please observe the Reply-To address |
Shielding 750 volt 3rd rail ?
On Thu, 14 Aug 2003 20:29:36 +0100 Clive D. W. Feather wrote:
} In article , Matthew } Malthouse writes } } British Rail, very seriously underinvesting, } } Nowhere near true. } } Read Roger Ford's column in the current (August) Modern Railways. } The gist? } } A detailed analysis of this canard. Basically, BR invested lots. } } The perception as long as I can remember has been that railways have } suffered from lack of funds. } } Yes, as in there's a lot of improvements that could have been done with } more money. But, unlike Railtrack, BR at least invested enough to keep } the network stable. Fine, I'll go with that. ;-) Come back BR! All is forgiven! Matthew -- Il est important d'être un homme ou une femme en colère; le jour où nous quitte la colère, ou le désir, c'est cuit. - Barbara http://www.calmeilles.co.uk/ |
Shielding 750 volt 3rd rail ?
Displaced Conductor rails do happen, but not as often as damaged
overhead wires. And it doesn't take as long to repair. C On Wed, 13 Aug 2003 07:07:29 +0000 (UTC), Mike Bristow wrote: In article , Boltar wrote: OTOH hand , when was the last time that you heard of trains being stuck or cancelled because the 3rd rail fell over? Sometime around last year, around Bank. I can't remember the details, but I think the central conductor rail "fell over", rather than the outer one. (OK: so it was trains being stuck/delayed/canceled because the 4th rail fell over, rather then the 3rd. And it was a rather unusual incident.) Life without sex just isn't life. Make love not war! |
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