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LUL insulator cleaning

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Backroom_boy

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Insulator cleaning or lack of it seems to be a big issue on a lot of US metro systems. The Washington Metro has suffered a lot of smouldering incidents with dirty insulators being the cause.

I've not heard of a similar issue on the London underground; is this because cleaning has been more consistent in London or because the nominal voltage in london is about 120V less or some other issue?

...or because the nominal voltage in london is about 120V less or some other issue?

Actually just realised it's even less as London is a 4 rail system so voltage is a max of +420v (with -210v on the return) I guess higher voltage systems will be more prone to flash over due to dirt.
 
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Philip Phlopp

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I'm tempted to suggest it's all of the third and fourth rail enthusiasts licking the conductor rail which keeps the insulators clean...

...but that would be mean. And almost unfounded.
 

Malcmal

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I'm tempted to suggest it's all of the third and fourth rail enthusiasts licking the conductor rail which keeps the insulators clean...

...but that would be mean. And almost unfounded.

Ha ha - I laughed at that. Reminded me of what I heard the initials BLS (Branch Line Society) really stands for - Bufferstop Licking Society.
 

Dstock7080

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Insulator cleaning or lack of it seems to be a big issue on a lot of US metro systems. The Washington Metro has suffered a lot of smouldering incidents with dirty insulators being the cause.

I've not heard of a similar issue on the London underground; is this because cleaning has been more consistent in London or because the nominal voltage in london is about 120V less or some other issue?



Actually just realised it's even less as London is a 4 rail system so voltage is a max of +420v (with -210v on the return) I guess higher voltage systems will be more prone to flash over due to dirt.
Most of the subsurface network is now 750v +500v -250v.
Cleaning of the insulators mostly takes place in station areas, freshly polished ones can often be seen.
 

Bucephalus

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I'm tempted to suggest it's all of the third and fourth rail enthusiasts licking the conductor rail which keeps the insulators clean...

...but that would be mean. And almost unfounded.
There's me thinking that rail enthusiasts and conductor rail enthusiasts were one and the same. I guess there's a potential difference
 

AlbertBeale

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There's me thinking that rail enthusiasts and conductor rail enthusiasts were one and the same. I guess there's a potential difference

As a one-time physics teacher, I appreciate that! About on a par with jokes I used to tell my classes.
 

edwin_m

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There's me thinking that rail enthusiasts and conductor rail enthusiasts were one and the same. I guess there's a potential difference
Running rail enthusiasts are fitter than conductor rail enthusiasts.
You didn't get any resistance from the students? Kids seem to have a potential for reacting to bad jokes
Does an argument between steam enthusiasts and third rail enthusiasts about the cleanliness of insulators involve the kettle calling the pot black?
 

AlbertBeale

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Sounds more positive than I expected, kids can be so negative at times

Maybe it depends on the style and culture of the school (and the era - this was some while back); also, with 6th-formers doing physics A-levels and S-levels, you're teaching students who're doing it because they want to - it's a generally supportive and co-operative environment. I also had to do a bit of other stuff, like teaching maths to not-very-enthusiastic 12-year-olds ... a rather different vibe...
 

rebmcr

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Maybe it depends on the style and culture of the school (and the era - this was some while back); also, with 6th-formers doing physics A-levels and S-levels, you're teaching students who're doing it because they want to - it's a generally supportive and co-operative environment. I also had to do a bit of other stuff, like teaching maths to not-very-enthusiastic 12-year-olds ... a rather different vibe...
You've replied to an electricity pun.
 

AlbertBeale

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You've replied to an electricity pun.

Aha - yes! Sorry not to have had the wit to carry on the humour of the thread... though the point I made was a serious comment on what is a common perception of how kids are... he says, trying not to look too foolish...
 
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