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Author Topic: Great Western Main Line electrification - ongoing discussion  (Read 53946 times)
Tim
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« Reply #510 on: November 08, 2018, 03:16:16 pm »


for those of you that doubted that Network Rail would install something in a tunnel that could rust..... the minister has confirmed it-
I saw this on the BBC and thought you should see it:

Severn Tunnel electrification kit deteriorating, minister admits - http://www.bbc.co.uk/news/uk-wales-politics-44690614

Here's the article for those that are interested -

https://www.walesonline.co.uk/news/severn-tunnel-shut-three-weeks-14785503

Does anyone know if it's true?
Smiley


I did post earlier that the construction team were informed of the harsh conditions and they did see example of existing equipment; from a brief chat I have had with someone involved in the project they have been montoring the install and there are areas of concern.   Also the lessons are being learnt to determin the levels of inspection, maintainance and what the renewals polocy should be (ie 10, 20, 30 years etc)



It is an extremely harsh environment 

Made worse I expect by running diesel trains in the tunnel which chuck out acidic gases

That will have limited effects, it more the damp atmospher in the tunnel

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YouKnowNothing
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« Reply #511 on: November 08, 2018, 11:26:05 pm »


for those of you that doubted that Network Rail would install something in a tunnel that could rust..... the minister has confirmed it-
I saw this on the BBC and thought you should see it:

Severn Tunnel electrification kit deteriorating, minister admits - http://www.bbc.co.uk/news/uk-wales-politics-44690614

Here's the article for those that are interested -

https://www.walesonline.co.uk/news/severn-tunnel-shut-three-weeks-14785503

Does anyone know if it's true?
Smiley


I did post earlier that the construction team were informed of the harsh conditions and they did see example of existing equipment; from a brief chat I have had with someone involved in the project they have been montoring the install and there are areas of concern.   Also the lessons are being learnt to determin the levels of inspection, maintainance and what the renewals polocy should be (ie 10, 20, 30 years etc)



It is an extremely harsh environment 

Made worse I expect by running diesel trains in the tunnel which chuck out acidic gases

That will have limited effects, it more the damp atmospher in the tunnel



Has it rusted again? Another tunnel closure over Xmas to fix the issue?
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onthecushions
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« Reply #512 on: November 12, 2018, 09:01:27 pm »

It's reported that the 13.29 Swansea - Paddington ran pan-up from Swindon - Causeway.

Dark horses.

OTC

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« Last Edit: November 13, 2018, 10:37:48 am by onthecushions » Logged
Adrian
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« Reply #513 on: November 14, 2018, 08:33:00 pm »

At last, a couple of wires have appeared on the Welsh side of the Severn Tunnel - along the Llanwern Straight, to be precise, though they're ones that go along the masts, not the catenary itself (I guess the lower one is some sort of earth connection, and the one on the top for power transmission?)  There is also a bit of knitting across the tracks at the substation at STJ.

Still no masts at STJ station itself, and at least a dozen still to go up between there and the tunnel.  Meanwhile at Newport there are men digging holes with spades for some of the remaining bases.  The steelwork there seems to have been going up in a somewhat random fashion, and it looks like one mast is due to go in half-way through the fence by the taxi rank!

Near Llanwern Steelworks there are some piled bases being used in pairs with what looks like a steel casting joining the piles and the mast attached in the middle.  I imagine this is because of the marshy ground, but what interests me most about these is whether they put in the piles an exact distance apart, or whether the castings are each custom-made.  But then, nothing on this project looks as if it's been done on the cheap.
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grahame
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« Reply #514 on: November 14, 2018, 08:54:17 pm »

At last, a couple of wires have appeared on the Welsh side of the Severn Tunnel ...

Electric traction has of course been in use ((here)) in Wales since 1958 and until 2001 that had overhead wires, though they have now been replaced with a more modern alternative.
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SandTEngineer
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« Reply #515 on: November 14, 2018, 09:01:02 pm »

At last, a couple of wires have appeared on the Welsh side of the Severn Tunnel ...

Electric traction has of course been in use ((here)) in Wales since 1958 and until 2001 that had overhead wires, though they have now been replaced with a more modern alternative.
Forgive me Grahame, but I thought the Tramway was cable operated.  The overhead wires were for telegraph communication to the moving cars only?
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grahame
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« Reply #516 on: November 14, 2018, 09:17:29 pm »

Forgive me Grahame, but I thought the Tramway was cable operated.  The overhead wires were for telegraph communication to the moving cars only?

Correct - but the cable has been pulled by electric motors since 1958 - thus "electric traction".  And I didn't say anything about the overheads being to power the things.
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SandTEngineer
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« Reply #517 on: November 14, 2018, 09:37:43 pm »

Forgive me Grahame, but I thought the Tramway was cable operated.  The overhead wires were for telegraph communication to the moving cars only?

Correct - but the cable has been pulled by electric motors since 1958 - thus "electric traction".  And I didn't say anything about the overheads being to power the things.
Ah, but one could argue then that actually its powered by Gas/Wind/Coal/Tide/Pumped Storage etc...... Grin
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« Reply #518 on: November 14, 2018, 11:55:16 pm »

...
Near Llanwern Steelworks there are some piled bases being used in pairs with what looks like a steel casting joining the piles and the mast attached in the middle.  I imagine this is because of the marshy ground, but what interests me most about these is whether they put in the piles an exact distance apart, or whether the castings are each custom-made.  But then, nothing on this project looks as if it's been done on the cheap.

Do you mean one like the stanchion at the left? Sorry it's such a busy picture; Reading's like that.

My theory on those (never having seen anything authoritative) is that it's to resist a side-force at the top without a stay. If you look closely at the top of that stanchion, there are two wires (catenary and contact) attached to clamps and going off to the right. They pull the top parallel to the track with about three tons of force combined. In most cases, such single uprights or pairs supporting portals are supported by stays - as is the portal in the picture.

In this case, there's stuff in the way where the piled base for a stay would have to go. The alternative would be a guy on the nearer side (i.e. opposite the wires) but there's stuff in the way there too. Hence the two bases, and perhaps a bigger steel section, so it can withstand the overturning moment.

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Adrian
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« Reply #519 on: November 15, 2018, 07:24:53 pm »

...
Near Llanwern Steelworks there are some piled bases being used in pairs with what looks like a steel casting joining the piles and the mast attached in the middle.  I imagine this is because of the marshy ground, but what interests me most about these is whether they put in the piles an exact distance apart, or whether the castings are each custom-made.  But then, nothing on this project looks as if it's been done on the cheap.

Do you mean one like the stanchion at the left? Sorry it's such a busy picture; Reading's like that.

My theory on those (never having seen anything authoritative) is that it's to resist a side-force at the top without a stay. If you look closely at the top of that stanchion, there are two wires (catenary and contact) attached to clamps and going off to the right. They pull the top parallel to the track with about three tons of force combined. In most cases, such single uprights or pairs supporting portals are supported by stays - as is the portal in the picture.

In this case, there's stuff in the way where the piled base for a stay would have to go. The alternative would be a guy on the nearer side (i.e. opposite the wires) but there's stuff in the way there too. Hence the two bases, and perhaps a bigger steel section, so it can withstand the overturning moment.

Yes - just like that, but oriented at right-angles to the track.  There are similar ones just for the stays, and those, of course, are parallel with the track - in other words there are some masts making use of 4 piles!
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« Reply #520 on: November 15, 2018, 08:18:58 pm »

...
Near Llanwern Steelworks there are some piled bases being used in pairs with what looks like a steel casting joining the piles and the mast attached in the middle.  I imagine this is because of the marshy ground, but what interests me most about these is whether they put in the piles an exact distance apart, or whether the castings are each custom-made.  But then, nothing on this project looks as if it's been done on the cheap.

Do you mean one like the stanchion at the left? Sorry it's such a busy picture; Reading's like that.

My theory on those (never having seen anything authoritative) is that it's to resist a side-force at the top without a stay. If you look closely at the top of that stanchion, there are two wires (catenary and contact) attached to clamps and going off to the right. They pull the top parallel to the track with about three tons of force combined. In most cases, such single uprights or pairs supporting portals are supported by stays - as is the portal in the picture.

In this case, there's stuff in the way where the piled base for a stay would have to go. The alternative would be a guy on the nearer side (i.e. opposite the wires) but there's stuff in the way there too. Hence the two bases, and perhaps a bigger steel section, so it can withstand the overturning moment.




The lower of the conductors will be the earth wire, the upper one is likely to be the ATF (Auto Transformer feed).  It is essential that during construction of the overhead line it is possible to bond the catenary and ATF to earth; even though the OLE and ATF will not have been made live they can be come charged due to static and induction.   


You will see as the wires are run out and placed on insulators either the conductors are directly clamped to a mast or are the work progresses removable earth bonds are fitted
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Western Pathfinder
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« Reply #521 on: November 18, 2018, 10:14:34 am »

Just found this on YouTube may be of interest?.
https://m.youtube.com/watch?v=5nLwKRtfOKs&feature=youtu.be
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SandTEngineer
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« Reply #522 on: November 18, 2018, 03:23:56 pm »

Just found this on YouTube may be of interest?.
https://m.youtube.com/watch?v=5nLwKRtfOKs&feature=youtu.be
Thanks for posting that. Interesting.  In my days on the WCML in the Late 1960/Early 1970s, the MK1 OLE wasn't that slack and I certainly don't remember that much uplift.  I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph Grin
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eXPassenger
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« Reply #523 on: November 18, 2018, 03:50:40 pm »

I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph

I do not think that H&S would allow that today.
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SandTEngineer
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« Reply #524 on: November 18, 2018, 03:58:57 pm »

I speak from a position of authority on that as I used to be hanging in a signal cage between tracks and having pantographs passing me at about 2.5m away at 100mph

I do not think that H&S would allow that today.
The cages were screened and earthed.  It wasn't possible to push even your fingures through the caging mesh so I don't see the problem.  And were quite a few electrical flashes as pantographs passed by as well (especially in frosty/icy weather).  I used to enjoy it.
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