GWML Electification

[R.Langley]

Total block at Reading this weekend, nothing runs between Didcot & Maidenhead or past Theale, 0001 hrs Saturday all the way through to early doors on Monday morning!

0200 Saturday to 0200 Monday.

[37114]

Just booked my train tickets for next week including my usual train which is the 0625 ex Chippenham on Monday, from reading the above I think I will pre warn the office I will be late....

[jim.snowdon]

Autotransformer feeders (ATF) run at 25kV to earth, but are 180* out of phase with the OLE, which gives a voltage between the ATF and OLE of 50kV. That enables more power to be distributed over a larger area than a conventional system where it's just the OLE at 25kV.

It's the standard system for high speed lines around the world - including HS1, and is also used on parts of the WCML and MML in the UK.

Although the original ATF electrification, which was on a US railroad nearly a century ago, used a 22kV single phase supply, transformed down to 11kV on the contact wire.

 

The benefit of using a 25-0-25kV arrangement is that the ATF feeder need only be insulated to 25kV standards, not 50kV, and that the same rules apply to both conductors in terms of the safety distances.

 

Jim

[jim.snowdon]

Total block at Reading this weekend, nothing runs between Didcot & Maidenhead or past Theale, 0001 hrs Saturday all the way through to early doors on Monday morning!

I believe the issue is that there is still work to be done by way of both the section proving and getting the wire runs completed to a state where they can actually be traversed by pantographs.

The project is getting to that stage where any delay has a real impact on the ability to deliver the now published start of electric operation, which may be a pain to us, but constitutes an emergency to the project managers who are now about to have to carry the can in earnest. I wouldn't relish being in their position but as it is only the chaos of the earlier stages of the project coming home to roost, it is difficult to have much sympathy.

 

Jim

[Mike Storey]

Troughing has been used at a number of stations - and photos appeared earlier in this thread.  Feeders seem to run all over the place at Reading I noticed today and some are obviously 'in the ground' so I expect that is what you saw.

 

I suspect that is indeed the case however two points emerge

 

1. Using the word in public information is rather stupid as it can convey the wrong impression (why an emergency?  Does that means it's dangerous?), and

 

2. Yet again it is a regrettable example of a scheme being run by what appear to be rank amateurs.  There are possessions every Sunday morning in the Reading area for the rest of this month (and possibly overnight from Saturday as well?) with an absolute fortune being spent on alternative road transport and even lines like the Henley branch (which could run with a normal service) having road replacements when a unit could be outstabled.  If these possessions aren't adequate to cover whatever they are meant to cover them someone has got the programme wrong and has incorrectly estimated the amount of work required (and has therefore sought extra possessions at short notice).  

 

Equally actually shutting the railway to do the job strikes me as farcical - especially when you consider that some electrification detail work is not even complete and is being done on weekdays while trains are running - as I saw today.  it might be worth looking at Reading on Saturday to see how many folk are out on site but I bet it won't be many judging by the last weekend shutdown.

 

Whilst not even attempting to excuse the project management of this at all, if it is indeed a possession for acceptance testing, it is impossible to run trains, due primarily to a substantial part of that being a requirement to prove all immunisation of signals and absence of wrong side failures, of aspects, interlocking, panel/VDU displays and so on, sequentially route by potential route. Whilst being well out of date now on the new forms of signalling and electrification, I cannot imagine this requirement would have changed. I apologise if there is some educative egg sucking here, or indeed that you were referring to sections unlikely to be under test (but I would imagine, given the huge span of control of the new signalling centres, and the apparent paucity of localised emergency control cabins in the GW plan, that the test section areas involved may be much larger now than we were used to?).

 

I do know that on the NLL and GE re- and new stringing and signalling, our, shall we say, more senior, consultant signalling and OLE engineers, had advised my programme team what periods to insert for acceptance testing, for our critical path, sectional works completion and acceptance (G6/7) timelines, which proved to be entirely inadequate, as it would appear that one or more of them had simply not kept up with new requirements. We fortunately learnt very quickly from the first few minor disasters, and adjusted all our future stages accordingly, albeit with some of the more imminent tests well within the normal request limits and thus "emergency" possessions (or in fact extensions of existing possessions).

 

It had been traditional for major inquests to be held on any project overruns or delays, with the object of finding someone (contractually, usually) to blame as much as what went wrong. Fortunately by then, what went wrong was far more important together with avoiding repetition, as became the objective of Alliancing. What might be speculated here is that there must be huge pressure on the planning managers to recover time on the programme overall, and one feature that always stands out on any programme is the, relatively huge period allowed for such testing on each section. It is a prime target for inexperienced or under-threat project managers. Alternatively, as with many other aspects of the GW prog, they may simply have not completed the works to be tested, within the programme allowed and hence final testing had to be put back entirely. I know where your money would be punted!

[jonathan452]

Time to get those wires up to Oxford

 

Oxford to become the first UK city to ban all petrol and diesel vehicles by 2020 - https://www.standard.co.uk/news/uk/oxford-to-become-the-first-uk-city-to-ban-all-petrol-and-diesel-vehicles-by-2020-a3656606.html

[chrisf]

Time to get those wires up to Oxford

 

Oxford to become the first UK city to ban all petrol and diesel vehicles by 2020 - https://www.standard.co.uk/news/uk/oxford-to-become-the-first-uk-city-to-ban-all-petrol-and-diesel-vehicles-by-2020-a3656606.html

 

Dream on x 2

 

Chris

[caradoc]

The way things are going there's more chance of electrifying to Thurso than to Oxford. Besides, I would rather see Oxford City Council concentrate on getting the current bus services to run properly; On recent visits the service has been an utter shambles due to, among other things, the Westgate Centre rebuilding, closure of Queen St to buses, and resurfacing on Folly Bridge. It has taken longer to get by bus from Oxford station to my Mum's house (4 miles) than it took the train to get from Paddington to Oxford (63.5 miles) !

[lmsforever]

Oxford City council have a long track record for hair brained schemes that don't benefit anyone who has to carry out any business in the town ,plus of course you stand a good chance of being flattened by a bus! As to electric trains to Oxford I totally agree that they will not happen for a long while possibly never,the only reason for wires would be if they continued  to Birmingham ,another very long shot.Also I can see locals only from Didcot as the 800,s will be required for the mainline with a few through services am pm that's all they will get..,Northwards is a strange situation as only a few locals trundle to Banbury and Cross Country  is favoured to Birmingham .I can see that Chiltern is going to be the service for London a much better timetable and trains ,seems as GWR don't want any commuters.

[The Stationmaster]

I believe the issue is that there is still work to be done by way of both the section proving and getting the wire runs completed to a state where they can actually be traversed by pantographs.

The project is getting to that stage where any delay has a real impact on the ability to deliver the now published start of electric operation, which may be a pain to us, but constitutes an emergency to the project managers who are now about to have to carry the can in earnest. I wouldn't relish being in their position but as it is only the chaos of the earlier stages of the project coming home to roost, it is difficult to have much sympathy.

 

Jim

 

Very much the case I think Jim - this project has been a shambles since Day 1 as far as work on the ground is concerned and if they need to test signalling system immunisation (on a brand new signalling system with no track circuits?) over umpteen successive weekends there's something well adrift in the state of Denmark - especially as they didn't do it with long total possessions like that east of Maidenhead or at Didcot for exactly the same signalling system.  

 

it simply suggests to me what I have been able to see with my own eyes - work at Reading is not complete (there was still installation work going on on Monday this week) and there is probably concern about the quality of some of the installation work (although an insulator has finally appeared in the contact wire on Platform 3).  I wouldn't mind betting anyone with half an eye on what has been done suspects that one reason for having numerous shutdowns 'for testing' is because there's a concern somewhere in NR that 25kv might run straight to ground when some of this lot is powered up.

 

There is work going on west of Reading on a section which has taken over 3 years to electrify 14 miles of plain line plus three single lead running junctions and which still had detail changes being made to it nearly a year after it was officially turned on and started to be used under test conditions by electric trains.

 

I was talking to a past senior colleague recently and he and many other former senior WR managers have nothing short of contempt for this mismanaged shambles of a scheme together with NR's seeming inability to sort out train services with operators for either jobs like this or in the event of perturbation situations.  The cost of all these shutdowns must be astronomical let alone the inconvenience for passengers while some of the replacement 'bus services (TOC planned of course) appear to have been put together by folk with no knowledge at all of what could still run railwaywise in the area. 

[dibber25]

Here's the live feeder troughing route at Tilehurst being installed in July last year

 

DSCF9322.jpg

 

Oh, that's exquisite! A real work of art! The finest work in England? (CJL)

[jim.snowdon]

It's strage to think that what was once BR Southern Region has a vast network of 33kV cables running alongside its tracks that has, for the most part, been there since the 1930s, earlier in some parts, all without the fuss and bother of the Western's ATF wire.

 

That said, the whole issue of having to cable it through the station (which practice is not universal) will have stemmed from the restriction on having exposed high voltage equipment above publicly accessible areas of the railway. It is, though, quite permissible to run overhead conductors at much greater voltages above areas of common land.

 

Jim

[david.hill64]

That said, the whole issue of having to cable it through the station (which practice is not universal) will have stemmed from the restriction on having exposed high voltage equipment above publicly accessible areas of the railway. It is, though, quite permissible to run overhead conductors at much greater voltages above areas of common land.

 

Jim

Jim, my understanding regarding overhead conductors was the same as yours, then I saw this:

 

https://commons.wikimedia.org/wiki/File:Esta%C3%A7%C3%A3o_de_Albufeira_%E2%97%8F_Ferreiras,_2_October_2015_(6).JPG

 

Different interpretation of the same rule.

[Zomboid]

It's strage to think that what was once BR Southern Region has a vast network of 33kV cables running alongside its tracks that has, for the most part, been there since the 1930s, earlier in some parts, all without the fuss and bother of the Western's ATF wire.

 

The ATF needs to be in the air for immunisation reasons. The voltage, and hence current, opposes the contact system and cancels it out to a large degree with respect to lineside cables. Putting it in a trough is possible but creates much more immunisation work. I think cabling is considerably more expensive than hanging the wire off the back of masts that you have to provide anyhow, too.

The Southern system is 3 phase with well balanced loads, which is a totally different beast as it's pretty much self-immunising. And there is no other reason to build masts, but there is a reason why electricity distribution networks rely on aerial conductors wherever possible.

[jim.snowdon]

The ATF needs to be in the air for immunisation reasons. The voltage, and hence current, opposes the contact system and cancels it out to a large degree with respect to lineside cables. Putting it in a trough is possible but creates much more immunisation work. I think cabling is considerably more expensive than hanging the wire off the back of masts that you have to provide anyhow, too.

The Southern system is 3 phase with well balanced loads, which is a totally different beast as it's pretty much self-immunising. And there is no other reason to build masts, but there is a reason why electricity distribution networks rely on aerial conductors wherever possible.

A great many lineside cables are now fibre optic, which are intrinsically immune to electromagnetic interference, so they aren't an issue. It is also standard practice, to avoid interference, for signalling and telecommunications cables to be put on the opposite side of the track to the HV power cables, even on the Southern. Maintaining separation is a good way of reducing interference as the magnetic and electric field strengths reduce as the square of the distance from the conductor. A great many of the track circuits have also been replaced by axle counters, which are themselves intrinsically immune.

The HV cables on the Southern may be carrying balanced loads, but that does not take away the existence of magnetic fields in the vicinity of the cable.

As far as electricity transmission networks are concerned, not only are overhead lines cheaper compared to cables, but they have a better power factor over longer distances. A further factor in the railway's favour is that they do not have to bury their HV cables and the cost of trough route has to be compared with the cost of the additional steel required to support the aerial ATF cable far enough away from the rest of the OLE to allow the latter to be worked on safely whilst the ATF wire remains energised.

 

Jim

[Coryton]

further factor in the railway's favour is that they do not have to bury their HV cables and the cost of trough route has to be compared with the cost of the additional steel required to support the aerial ATF cable far enough away from the rest of the OLE to allow the latter to be worked on safely whilst the ATF wire remains energised.

 

 

Yes I expect we'd see a lot more power lines on the ground if they could just be layed in troughs rather than decently buried.

[SouthernMafia]

A rather fantastic quip from Paul Clifton on South Today this evening, says what has been said many a time in this thread:

 

"There's a new phrase for being unable to organise a drinks party in a brewery, it's called Network Rail project management!"

[4630]

A rather fantastic quip from Paul Clifton on South Today this evening, says what has been said many a time in this thread:

"There's a new phrase for being unable to organise a drinks party in a brewery, it's called Network Rail project management!"

Whilst I’m no defender of poor management in any form, and the GWML electrification seems to me to be in many respects a text book case of how not to manage a major project, I feel that Paul Clifton’s quip is very much a cheap shot.

 

It’s not as if the BBC is immune from poor management, is it. Jimmy Savile anyone?

[Zomboid]

EM Interference isn't the issue so much as potential hazardous accessible voltages (or rather compliance with the Electricity at Work act and the relevant BS/EN). Hazardous voltages can be induced into anything metallic. Having the + and - currents in close proximity is a very effective way of reducing the inductive effect. It's how Booster transformers work as well, in fact it's the whole point of BTs, which would be worse than useless if the return conductor was in a trough near any other cables for long run. Fibre counts as a potential victim cable too, since they generally have metallic sheaths.

 

The 3 phase cables on the southern do actually pretty much take away the magnetic fields under load conditions. Inside the cable (or in the immediate vicinity where single core cables are used) there will be some fields, but they cancel each other out pretty effectively because of the 120* phase separation. It's a bit different during an earth fault, but much of the current there flows back to source in the cable sheath, so a lot of cancelling goes on that way, and the rules during a transient fault condition are less onerous than is permitted as a permanent situation.

[Re6/6]

Travelled  to and from BPW today where there were no masts visible anywhere and travelling east to Gloucester there were sporadic posts up to the junction. Some had registration arms swung out of the way and others none.

 

Looking west whilst travelling up into BPW there there was full wiring visible. No rhyme or reason for this seemingly chaotic state of affairs. Frankly it would seem that NR's planning, or rather lack of it, just beggars belief.

[Northroader]

The overhead you see west of BTL PKW is just the depot in the triangle, which has been wired for some time.

[The Stationmaster]

Travelled  to and from BPW today where there were no masts visible anywhere and travelling east to Gloucester there were sporadic posts up to the junction. Some had registration arms swung out of the way and others none.

 

Looking west whilst travelling up into BPW there there was full wiring visible. No rhyme or reason for this seemingly chaotic state of affairs. Frankly it would seem that NR's planning, or rather lack of it, just beggars belief.

 

Going on in the same (in)efficient manner which they have followed since this project started.

[jim.snowdon]

EM Interference isn't the issue so much as potential hazardous accessible voltages (or rather compliance with the Electricity at Work act and the relevant BS/EN). Hazardous voltages can be induced into anything metallic. Having the + and - currents in close proximity is a very effective way of reducing the inductive effect. It's how Booster transformers work as well, in fact it's the whole point of BTs, which would be worse than useless if the return conductor was in a trough near any other cables for long run. Fibre counts as a potential victim cable too, since they generally have metallic sheaths.

Fibre optic cables don't necessarily have metallic armoured sheaths. They have no need of them for either EM screening or for earthing live conductors in the event of damage. Beyond that, it is important to distinguish between voltages that may be induced by either inductive or capacitive coupling and the energy in any conductor. Both are heavily influenced by the distance between the conductors. Also worth remembering is that some AC railways adopt the practice of running a parallel return conductor at ground level as a means of providing a lower impedance path than just the running rails.

 

Of course, on the DC railway, there are some rather substantial magnetic fields round the traction conductors, which are carrying currents an order greater than those in AC systems.

 

Jim

[jonny777]

It seems the naysayers in the media are having trouble once again containing their delight at the failure of something new.

 

One wonders if all these reporters have ever made any kind of mistake themselves, which enables them to speak in such sanctimonious tones?

Edited October 16, 2017 by jonny777

[Edwin_m]

It seems the naysayers in the media are having trouble once again containing their delight at the failure of something new.

 

One wonders if all these reporters have ever made any kind of mistake themselves, which enables them to speak in such sanctimonious tones?

I think it's fair to report it if there is water pouring from the ceiling in the first passenger working.  Not a failure mode I ever recall with older stock, and it didn't even go near Dawlish!

 

http://www.bbc.co.uk/news/uk-england-bristol-41633356