Harlan Cage
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My apologies as I did not intend to drift off topic. I thought I saw a 390 with one pantograph but I must have been mistaken.
HC
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Neutral sections
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My apologies as I did not intend to drift off topic. I thought I saw a 390 with one pantograph but I must have been mistaken.
HC
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Zoidberg
Established Member
My apologies as I did not intend to drift off topic. I thought I saw a 390 with one pantograph but I must have been mistaken.
HC
Oh it was me who was risking off-topicness.
They certainly have two and I've only ever seen the rear in use. At a terminus I've seen what was the rear lowered and what was the front raised ready for departure in the opposite direction.
Just wondered why and snowball has offered plausible reasons.
So we were stopped for an hour for no reason??
I had heard that the reason the rear pantograph was used was so that if the train were to lose a pantograph due to some obstruction on the OHLE then the other pantograph should be beyond that obstruction and so the train can continue. Similarly for a neutral section the other pantograph is beyond the neutral section so there is no problem pulling away. If you use the front pantograph then the other pantograph needs to get past the same place that stopped the first one working.
edwin_m
Veteran Member
I've heard it said that the rear pantograph is used because if it is damaged by something on the line, the front pantograph will already have passed beneath the damaged area so should be OK. Not sure how true this is, and I think it was in the context of French locos anyway.
carriageline
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I'm not entirely sure why it should be the rear one! I was always told the knuckle on the pants should be facing the direction of travel, as i read it on an incident report it may of played a part in a dewirement
Zoidberg
Established Member
I did wonder if it was about ensuring that the contact bit was dragged rather than pushed.
Thanks, all, for your thoughts on this.
Would the Line Light normally be lit if the VCBs are open?
The first image shows a section insulator not a neutral section and the newer type magnets are not the large yellow ones but much smaller white magnets.
--- old post above --- --- new post below ---
That is correct, although use of the rear pantograph is company policy and the train will work the same whatever one is used and you will sometimes see one running with the front pan, which is usually after a fault etc
--- old post above --- --- new post below ---
The driver would have believed they were in the OHNS. The two VT services behind were set back to Willesden North Jn to crossover so an assisting 350 could rescue your train but the OHL team arrived at site first and confirmed the train was actually not in the dead section.
dk1
Veteran Member
Correct!! The idea was that should the knitting come down or debris hit the pan it wouldn't pass down the train possibly damaging the rear one.
Zoidberg
Established Member
This is not meant to imply criticism, but had the driver got out and looked, would it have been apparent to which part of the Neutral Section the train's pantograph was connecting?
I ask that in view of the physical description given of the OHLE Neutral Section further up the thread at post #4.
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No, it all looks like wire. Perhaps if you looked very closely you could see what is live and 'dead' but I've certainly never been shown this. If I'm inside the APC magnets I'm in the NS.
Sometime within the last few years on a Sunday an East Coast train stopped with the loco pantograph stopped in a neutral section near Ardsley, Leeds due to tresspases on the line as the driver was in the DVT at the front she didn't realise the position of the pantograph (no reflection on this driver just one of those things) train rescued by thunderbird BUT the following Leeds to London train was an HST which was driven by her husband and was diverted to run via Hambleton. No doubt words were said at home later.
scott118
Member
the make up of the NS is - APC magnets, 100ft run in, 5ft ceramic beads, 5ft dead wire, 5ft ceramic beads, 40ft run out, APC magnets. 155ft total
Zoidberg
Established Member
Thanks. Question asked and answered.
It's certainly not a reflection on the driver who was blameless here as it wasn't a case of her not realising where the pan was. If you are told to stop the train for reasons like trespassers you stop immediately using the emerg brake. You don't just try and clear the points/reach the station/pass the neutral section etc, you apply the emerg brake straight away otherwise if you hit the trespasser it is on your head for ignoring the stop order. Once the emerg brake is applied it is locked on and can't be released until the train is at a stand. The driver has no control once the emerg brake is activated.
Joseph_Locke
Established Member
This would suggest that it is fed straight off the pan, as I thought the APC gear opened the VCB to prevent the driver taking power? I suppose in the case of train that is pan-gapped it makes do difference.
Neutral sections and associated signalling are designed so that during everyday normal running electric traction does not stop with its pan in the dead zone.
The ones on the CRE-MAN line by Sydney bridge where moved because of trains being stopped on the approach to Crewe, designers take measurements of all electric traction and where there pans sit in relation to the the location of neutral sections and signalling
The ones on the CRE-MAN line by Sydney bridge where moved because of trains being stopped on the approach to Crewe, designers take measurements of all electric traction and where there pans sit in relation to the the location of neutral sections and signalling
The APC does open the VCB. If the VCB is open no line light will be lit. However with multiple pans being up (ie double/treble units) the 25kv does not move between units so a driver would see when passing a NS (on a double unit) line light out, VCB light on and then line light on, VCB light on.
driver9000
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Just to upset that theory the line light on a 350 stays on when passing through a neutral section when the VCB opens.
Really? How can it as the line light indicates electricity reaching the unit by either OHL or 3rd rail. Is its in a NS then it can't possibly be getting any power. Unless it's to do with the computer being too slow to update the indicator?
driver9000
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Yes really. The VCB illuminating is the indicator power has been cut for the neutral section. I'm not sure why it stays on but it does and is on pretty much all the time as long as the pan is up and more than 17kv is in the wire. Loss of line light will throw up a TMS fault for loss of voltage so it may be connected to avoiding spurious faults.
edwin_m
Veteran Member
On the Desiro units mentioned above, the line light must be connected (very indirectly) to the pantograph side of the VCB.
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From the replies from drivers to this thread, it would seem to differ class-to-class.
edwin_m
Veteran Member
Previous post clarified.
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