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Author Topic: Great Western Main Line electrification - ongoing discussion  (Read 122386 times)
ellendune
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« Reply #600 on: December 02, 2018, 12:25:07 pm »

Yes, Probably dead in the water, Better to get Bath Electrified, which should be next year,The Government will have more money by not giving it to the EU.

Quite apart from payments during the transition, and depending on the trade deal eventually negotiated, possibly some payments beyond. Then there is the cost of the several thousand extra civil servants (many already recruited) who will be required to do the things the EU currently does for us.

And there is then the fact that most of the money to the EU is revenue and electrification is capital investment. 
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Dispatch Box
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« Reply #601 on: December 02, 2018, 12:30:26 pm »

Yes, Probably dead in the water, Better to get Bath Electrified, which should be next year,The Government will have more money by not giving it to the EU.

Quite apart from payments during the transition, and depending on the trade deal eventually negotiated, possibly some payments beyond. Then there is the cost of the several thousand extra civil servants (many already recruited) who will be required to do the things the EU currently does for us.

And there is then the fact that most of the money to the EU is revenue and electrification is capital investment. 

Wonder what the final cost of this Brexit thing will be?. And who thought of having a referendum in the first place.
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onthecushions
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« Reply #602 on: December 02, 2018, 02:05:58 pm »


My preference for DC extensions would be to use overhead wires. The kit for OLE was in fact developed for DC, with the contact wire gauges of 107mm2 and 120mm2 being used for 550V and 750V tramways/LR. I imagine that 3rd rail extension costs would have tracked with OLE, still giving OLE a marginal advantage. It would need either dedicated stock or a second LV pantograph but would prepare the way for seamless 25kV conversion.

Another link is the use of 33kV supplies to the 750V substations. It seems that the only real difference in equipment specifications between 25kV and 33kV systems is the transformer turns ratio.

I would like to see progress in my lifetime.

OTC

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YouKnowNothing
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« Reply #603 on: December 02, 2018, 02:33:56 pm »


I wonder what the cost savings for all the structures not requiring the additional height?


My preference for DC extensions would be to use overhead wires. The kit for OLE was in fact developed for DC, with the contact wire gauges of 107mm2 and 120mm2 being used for 550V and 750V tramways/LR. I imagine that 3rd rail extension costs would have tracked with OLE, still giving OLE a marginal advantage. It would need either dedicated stock or a second LV pantograph but would prepare the way for seamless 25kV conversion.

Another link is the use of 33kV supplies to the 750V substations. It seems that the only real difference in equipment specifications between 25kV and 33kV systems is the transformer turns ratio.

I would like to see progress in my lifetime.

OTC


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ellendune
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« Reply #604 on: December 02, 2018, 02:40:49 pm »


My preference for DC extensions would be to use overhead wires. The kit for OLE was in fact developed for DC, with the contact wire gauges of 107mm2 and 120mm2 being used for 550V and 750V tramways/LR. I imagine that 3rd rail extension costs would have tracked with OLE, still giving OLE a marginal advantage. It would need either dedicated stock or a second LV pantograph but would prepare the way for seamless 25kV conversion.

Another link is the use of 33kV supplies to the 750V substations. It seems that the only real difference in equipment specifications between 25kV and 33kV systems is the transformer turns ratio.

I would like to see progress in my lifetime.

OTC

You are still forgetting the additional substations the cost of rectifiers and the additional power losses due to the lower voltage (they reduce with the square of the voltage).  Also remember that most DC electric trains (and all modern ones) are dual voltage inside even if they don't have a pantograph. They could easily have a pantograph added and run on 25kV.
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onthecushions
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« Reply #605 on: December 02, 2018, 04:22:47 pm »


You are still forgetting the additional substations the cost of rectifiers and the additional power losses due to the lower voltage (they reduce with the square of the voltage).  Also remember that most DC electric trains (and all modern ones) are dual voltage inside even if they don't have a pantograph. They could easily have a pantograph added and run on 25kV.

We are really only thinking of the gaps in Reading - Gatwick, Uckfield etc.

Anything outside of the old SR (and Merseyrail!) area would of course be 25kV, as you say. It would still need to be affordable, though.

I imagine that clearances would be much the same as it is contact more than flash-over that is the risk.

OTC

OTC
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Electric train
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« Reply #606 on: December 02, 2018, 07:12:01 pm »

Happy to have third rail up from Southampton area to Wiltshire and taking it to Bristol; I doubt the good folks of Bath would complain about it being unsightly.

Apart from the safety considerations, the additional cost of DC power equipment (more substation and the need for rectifiers). Does the amount of traffic justfy electrification on this line? Surely there are higher priorities. It cannot even be justified as infill! Even west of Bathampton there would only be the Southampton Bristol services using it as the IET's don't run on DC. Electrifying Bathampton to Bristol on 3rd Rail would be extremely short-sighted and a waste of money! 

New electrification should be 25kV OLE.




Yes, Probably dead in the water, Better to get Bath Electrified, which should be next year,The Government will have more money by not giving it to the EU.  I Am lead to believe from information I have, is that Bath has part been started on and just needs finishing off by completing the Resignalling Then putting up the wires.


The problem at Bath Spa station and 25kV is one of electrical clearance due to the cant (the result of the curve) and the placement of the Pan over the coach doors, it is a problem that currently has no resolution suitable for ORR agreement, Sydney Gardens does have an acceptable solution.



My preference for DC extensions would be to use overhead wires. The kit for OLE was in fact developed for DC, with the contact wire gauges of 107mm2 and 120mm2 being used for 550V and 750V tramways/LR. I imagine that 3rd rail extension costs would have tracked with OLE, still giving OLE a marginal advantage. It would need either dedicated stock or a second LV pantograph but would prepare the way for seamless 25kV conversion.

Another link is the use of 33kV supplies to the 750V substations. It seems that the only real difference in equipment specifications between 25kV and 33kV systems is the transformer turns ratio.

I would like to see progress in my lifetime.

OTC



Pantographs for 25kV ac are not suitable for dc even at 1500V

It is not practical to use 33kV system to supply 25kV this is due to the large in balance caused by the 25kV being single phase, it cause negative phase sequence a large circulating current in the 132/33kV grid transformer
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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".
eXPassenger
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« Reply #607 on: December 02, 2018, 09:35:54 pm »

The problem at Bath Spa station and 25kV is one of electrical clearance due to the cant (the result of the curve) and the placement of the Pan over the coach doors, it is a problem that currently has no resolution suitable for ORR agreement, Sydney Gardens does have an acceptable solution.

So are you saying that there is a fundamental problem to electrifying Chippenham to Bristol TM?

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« Reply #608 on: December 02, 2018, 10:04:22 pm »

The problem at Bath Spa station and 25kV is one of electrical clearance due to the cant (the result of the curve) and the placement of the Pan over the coach doors, it is a problem that currently has no resolution suitable for ORR agreement, Sydney Gardens does have an acceptable solution.

So are you saying that there is a fundamental problem to electrifying Chippenham to Bristol TM?

There is, yes.   There will be a solution to it, but as the electrification of that part of the route has been descoped by the DfT no one has the budget hence the time and resources to solve it
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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".
eXPassenger
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« Reply #609 on: December 02, 2018, 10:45:46 pm »

The problem at Bath Spa station and 25kV is one of electrical clearance due to the cant (the result of the curve) and the placement of the Pan over the coach doors, it is a problem that currently has no resolution suitable for ORR agreement, Sydney Gardens does have an acceptable solution.

So are you saying that there is a fundamental problem to electrifying Chippenham to Bristol TM?

There is, yes.   There will be a solution to it, but as the electrification of that part of the route has been descoped by the DfT no one has the budget hence the time and resources to solve it

Thank you.  I had not previously seen any reference to this.
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Noggin
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« Reply #610 on: December 02, 2018, 10:59:55 pm »

The problem at Bath Spa station and 25kV is one of electrical clearance due to the cant (the result of the curve) and the placement of the Pan over the coach doors, it is a problem that currently has no resolution suitable for ORR agreement, Sydney Gardens does have an acceptable solution.

So are you saying that there is a fundamental problem to electrifying Chippenham to Bristol TM?

There is, yes.   There will be a solution to it, but as the electrification of that part of the route has been descoped by the DfT no one has the budget hence the time and resources to solve it

I though that was why they built the platforms out?
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Drkpm
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« Reply #611 on: December 05, 2018, 08:38:49 pm »

Does anyone know why, none of the IEP,s that I have watch today (5th) 5 sets up and 6 sets down both 5, 2x5 and 9 car have either arrived or departed Swindon “ Pan Up “
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onthecushions
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« Reply #612 on: December 05, 2018, 09:47:58 pm »


I understand that Swindon- Didcot OLE is OOU this week for attention.

It's very early days.

OTC
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paul7755
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« Reply #613 on: December 05, 2018, 10:13:14 pm »


I understand that Swindon- Didcot OLE is OOU this week for attention.

It's very early days.

OTC

Is it ‘attention’ or energising & testing Cocklebury sidings?

Paul
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TonyK
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« Reply #614 on: December 05, 2018, 11:09:57 pm »


We are really only thinking of the gaps in Reading - Gatwick, Uckfield etc.

Anything outside of the old SR (and Merseyrail!) area would of course be 25kV, as you say. It would still need to be affordable, though.

I imagine that clearances would be much the same as it is contact more than flash-over that is the risk.

OTC

I recall a senior manager of NR, being interviewed after the third rail had iced over and failed, saying that if we were starting from scratch, we wouldn't use third rail anywhere. That should inform the strategy for the future.

Yes, Probably dead in the water, Better to get Bath Electrified, which should be next year,The Government will have more money by not giving it to the EU.  I Am lead to believe from information I have, is that Bath has part been started on and just needs finishing off by completing the Resignalling Then putting up the wires.

They say that a pessimist is an optimist with experience. I am normally glass half full, but I don't recall anything about electrification being printed on the side of that red bus. I will bet you a peak return to Paddington against a single from Lawrence Hill to Stapleton Road that the NHS won't see anything like the £350 million per week that was offered - more like £35, if that. I might be wrong, but then I am old enough to have voted in the referendum in 1975. Sadly for me, my economic migrant forebears washed up from Ireland too long ago for me to be able to get an Irish passport.
« Last Edit: December 05, 2018, 11:30:29 pm by Tony (Formerly FT, N!) » Logged

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