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| Major delays due to fractured gas main 10/02/2016 at 21:46 #80562 | |
northroad
870 posts |
Like many others today I was caught up in the severe problems between Darlington and Newcastle due to a major gas leak next to the line just outside Durham. I was travelling on the 1N12 10:30 ex Kings Cross. We had just started away from Northallerton and the brakes went on. Half in and half out of the station. We were kept well informed by the on train supervisor who explained that all trains in the area had been stopped because of a request to switch off the current. We did eventually get to Darlington after a short time and they had managed to route us into Platform 1. Lucky for me that was where I was going but I believe that was as far as it went before being terminated and sent back south. Quick question for all of you signallers out there. Would the power isolation have had the result of turning all signals in the area to red or would it have been a blanket emergency turning all signals to red and then a power isolation. There must have been a few SPAD's as a result I would have thought and a lot of explaining to do as a result. I came back on a service that was also terminated at Darlington and sent back south so it was really no hardship but this must have been a logistics nightmare. Geoff Log in to reply |
| Major delays due to fractured gas main 10/02/2016 at 22:18 #80567 | |
Peter Bennet
5363 posts |
Looks like some of the HSTs were diverted, presumably via Sunderland. Peter I identify as half man half biscuit - crumbs! Log in to reply |
| Major delays due to fractured gas main 10/02/2016 at 23:36 #80569 | |
dwaynedibley
30 posts |
In a situation like this the signaller would likely take several actions to stop trains. Firstly I would have made a railway emergency group call to all trains in the affected area over the GSMR system (GSMR is a radio system used for communication between signallers and trains and other railway personnel). Doing so sounds an alarm in the cab of every train in the area and when the drivers hear this they will apply the emergency brake. I would then operate the signal group replacement switch for the affected area which would have put all signals in the affected area to danger. In reality both of these actions can be done within seconds of the signaller identifying the need to stop trains. The signalling system and the traction current system are operated separately. The signaller would be responsible for stopping trains and contacting the electrical control room operator who would then be responsible for an "emergency switch off" of the traction current. A lot of drivers would have received a change of aspect and subsequently passed a signal at danger, but this would not be classed as a SPAD in the technical sense as the signaller intentionally put signals back in front of the driver in such a way that the driver would be unable to avoid passing the signal at danger. This would often now be referred to as a SPAR (signal passed at red) although that isn't an official railway term. Last edited: 10/02/2016 at 23:41 by dwaynedibley Log in to reply |
| Major delays due to fractured gas main 11/02/2016 at 09:31 #80574 | |
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kbarber
1712 posts |
It's not impossible, in a situation such as this, that an emergency service (or National Grid) requested an isolation. In that case they will have numbers for direct lines; quite what exists these days I don't know but I suspect there will be lines to both the Electric Control Room and an operations control. If I were the gasman in this situation I'd quite likely want the juice off first so it's possible a number of trains found out about it when they lost line volts. But I'd be on to Control pretty quick as well, so the diesel traction in the area would get the GSMR shout and emergency replacements pretty quickly (reckon about 30sec later, I'd think).
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| Major delays due to fractured gas main 11/02/2016 at 12:50 #80580 | |
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northroad
870 posts |
Thanks for the responses guys. Not being in the industry and fully knowing what would have happened in response to the call was why I raised the question. The fact that we at the time were at Northallerton some 25 miles approximately away from the incident at Durham left me rather surprised as to why the area affected would be so large instead of being closer to the problem. Is this now as a result of the control centres covering such large areas. Sorry if I appear dumb about this but I am really interested as to how these type of emergencies are handled. Geoff Log in to reply |
| Major delays due to fractured gas main 11/02/2016 at 14:01 #80583 | |
Steamer
3925 posts |
" said:Thanks for the responses guys.When an OHLE section needs to be isolated in an emergency, it's often the case that the ones adjacent to it will be isolated as well. This is because a voltage can be induced from the 'Live' section to the 'Isolated' section where the two meet. Although the 'Dead' section won't be anything near the usual 25kV, it could still be nasty. It's possible, therefore, that they had to isolate a larger section initially before taking reducing the extent of the isolation. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
| Major delays due to fractured gas main 11/02/2016 at 14:36 #80585 | |
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Peter Bennet
5363 posts |
Which IECC covers Northallerton? Darlington is Tyneside, but not sure where the boundary with York is. if it involved two boxes then that must add to the complication. As for isolating the O/H can that be done by "Neutral Section" for want of a better phrase. If so they are reasonably short e.g. there's one just South of Biggleswade and the next is just short of Hitchin.
I identify as half man half biscuit - crumbs! Log in to reply |
| Major delays due to fractured gas main 11/02/2016 at 14:50 #80587 | |
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Steamer
3925 posts |
" said:Which IECC covers Northallerton?York, the boundary is about a mile north of Northallerton, just past the junction with the Redmire line. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
| Major delays due to fractured gas main 11/02/2016 at 19:44 #80592 | |
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casey jones
72 posts |
A few diverts round the durham coast via sunderland with the HSTs yesterday and has been used quite a lot with the WCML sleepers recently
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| Major delays due to fractured gas main 12/02/2016 at 12:08 #80613 | |
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kbarber
1712 posts |
An emergency isolation is always all lines between any set of neutral sections. That's partly because of the risk of induced voltages. But it's also because breaking a circuit under load has the potential to create some interesting fireworks; the breakers at neutral sections are designed to break maximum currents under load, whereas mid-section switches can only be operated when it is certain no current is being fed through them. There's also the risk of a train movement bridging out a line insulator at a switch and re-livening the dead section, whereas a neutral section is precisely that - there is an actual dead section in the OHLE (usually only about 10 or 15 feet long these days), connected to earth (so any arc that does get drawn simply blows out the breakers on the 'live' side without affecting the isolation) and with 'rod' insulators each side (so the pan runs over them without any possibility of livening anything). What that all means is that, once an emergency isolation has been granted anyone can safely approach the OHLE without risk. If it is likely to be a long job, OHLE linemen will be called out to carry out switching and earthing (and the rules for granting a normal isolation will be carried out by signalboxes) so the shortened isolation is fully protected and traffic can resume beyond the affected area. Log in to reply |
| Major delays due to fractured gas main 16/03/2016 at 20:42 #81231 | |
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Essexgirl
42 posts |
I was working that day in York IECC. The reason for the stop at Northallerton was that we got an instruction not to send trains to tyneside area, until they had 'sorted themselves out' with what was and what was not isolated and had dealt with trains as necessary, believe it or not we do actually try to hold trains in platforms rather than in the middle of nowhere, so that if required train doors can be released for passengers to try and find alternate travel.
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| Major delays due to fractured gas main 16/03/2016 at 21:31 #81232 | |
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northroad
870 posts |
" said:I was working that day in York IECC. The reason for the stop at Northallerton was that we got an instruction not to send trains to tyneside area, until they had 'sorted themselves out' with what was and what was not isolated and had dealt with trains as necessary, believe it or not we do actually try to hold trains in platforms rather than in the middle of nowhere, so that if required train doors can be released for passengers to try and find alternate travel.I am off there again tomorrow. See if you can stop it happening again please........ 
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