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Author Topic: A new concept for third rail electrification.  (Read 403 times)
martyjon
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« on: January 08, 2019, 07:11:10 pm »

Without wishing to invoke the 'self praise is no recommendation' I have been known to come up with some good ideas in the past but none with such brilliance as to earn me my knighthood but heres hoping this idea will break the famine.

Has it ever been suggested that future third rail electrification schemes be controlled by the signalling system ?

Taking the Reading to Gatwick route for example.

At Wokingham if the route towards Gatwick is electrified and the signalling system was used to energise the routes 'live' rail one signalling section ahead of the train service and de-energised behind the service in conjunction with the signalling aspects rear of the train would that work.

Come on all you experts, tell me why it cant be done and thus deny me that knighthood.

All said with tongue in cheek of course.
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ellendune
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« Reply #1 on: January 08, 2019, 07:27:03 pm »

I think one problem would be that no one would know whether the rail was live or not. People might become accustomed to it not being live and take even more risks. 
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martyjon
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« Reply #2 on: January 08, 2019, 07:41:17 pm »

I think one problem would be that no one would know whether the rail was live or not. People might become accustomed to it not being live and take even more risks. 

More stupid those people then.
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ellendune
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« Reply #3 on: January 08, 2019, 07:43:20 pm »

I think one problem would be that no one would know whether the rail was live or not. People might become accustomed to it not being live and take even more risks. 

More stupid those people then.


But a lot off such design issues are about protecting stupid people from themselves. 
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laird
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« Reply #4 on: January 08, 2019, 07:59:48 pm »

You could switch like Crossrail from a signaller to a Traffic Manager they can then hold Signalling and Electrical skills.
But more fundamentally switching is ideally minimised to protect the switching equipment.
In terms of safety until proven and locked off no-one should be working near a bare conductor e.g. third rail so procedurally it wouldn't matter if it was switched on or off after each train.
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Oxonhutch
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« Reply #5 on: January 08, 2019, 08:51:45 pm »

People might become accustomed to it not being live and take even more risks. 

[TiC] Yes, but they would only be electrocuted before being run-over!  Shocked [/TiC]
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Red Squirrel
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« Reply #6 on: January 08, 2019, 09:19:11 pm »


Has it ever been suggested that future third rail electrification schemes be controlled by the signalling system ?


I think the main problem with this suggestion is that it contains the phrase 'future third rail electrification'. Syntactically and grammatically there is nothing wrong with this, but the same could be said of the phrase 'vegetarian butcher's shop'.
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ellendune
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« Reply #7 on: January 09, 2019, 12:00:42 am »

In terms of safety until proven and locked off no-one should be working near a bare conductor e.g. third rail so procedurally it wouldn't matter if it was switched on or off after each train.

Yes so far as working on the line.

But if potential trespassers hear that it is only on when there is a train coming they are more likely to trespass and then get caught out!
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TaplowGreen
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« Reply #8 on: January 09, 2019, 05:07:41 am »

In terms of safety until proven and locked off no-one should be working near a bare conductor e.g. third rail so procedurally it wouldn't matter if it was switched on or off after each train.

Yes so far as working on the line.

But if potential trespassers hear that it is only on when there is a train coming they are more likely to trespass and then get caught out!

......but only once! 😉
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stuving
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« Reply #9 on: January 09, 2019, 10:19:41 am »

I wondered at first what the point of the suggestion was, but I guess it must be an attempt to make the system safe enough to overcome the ORR's current stance of "over our dead regulatory body". But if so, why the half measures?

For trams, we have the Alstom re-invention of ground pick-up, which seems to have convinced several powers that be of its safety. In that case the tram itself covers the live contact so it's out of reach of reckless humans, and I think a similar shielding arrangement is needed here. So you would need the third rail to be encased in insulation, with electronically switched contacts all along it, and a much longer pick-up "ski" along the train with insulation on top if it too. To meet the gauging constraints this will almost certainly need to be flexible, so as to follow the shape of the third rail without sticking out too far. Since its length determines the spacing of contact points, and the number of those will be a cost driver, you may and up extending this contact bar to the full length of the train (or at least EMU).

Obviously it will all be a bit more expensive, but at least it could largely get rid of the problem of "gapping".
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Electric train
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« Reply #10 on: January 09, 2019, 10:34:06 am »


Has it ever been suggested that future third rail electrification schemes be controlled by the signalling system ?

Yes and is in used today every day.

The traction current and the return current through Blackfriers station is squentially swithed through the platforms by the signalling track circuits.  This is part of the ad/dc traction power sepertaion.


The main problem in use on a "main line" would be having to energise sections in advance of the train also the conrail in the rear of the train will be live until the train has cleared the section.  There would not be any improvement in the safety of the system.  Inaddition often electrical sections a fed through due to a rectifier being out of use for maintenance or failure.


Technically posible but I doubt there would be much gained otherthan add an addition failure mode
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Mark Carne 26 June 2015 - "The challenges of delivering myriad improvement projects while still running a railway seven days a week were simply overwhelming".
onthecushions
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« Reply #11 on: January 09, 2019, 11:45:16 pm »


So, set the direction control, brakes off, open the power controller, nobble the driver vigilance device and given suitable signal positions, you could do without the driver!

Hmmmm,

OTC

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