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Great Western Electrification Progress

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JN114

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linuxlad7 said:
but still tripping??
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As far as I’m aware they have never been tripping, that appears just to be some unfounded wibble n various social media outlets...

When the news of the higher-than-anticipated corrosion was announced, some prominent and learned commentators suggested it could lead to trippings in a worst-case scenario - but we’ve never actually got there.
 
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hwl

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JN114 said:
As far as I’m aware they have never been tripping, that appears just to be some unfounded wibble n various social media outlets...

When the news of the higher-than-anticipated corrosion was announced, some prominent and learned commentators suggested it could lead to trippings in a worst-case scenario - but we’ve never actually got there.
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Agreed I really wouldn't expect tripping.

It'll just mean that the earthing isn't as good as you would expect and the time to trip if something does happen could increase by a few milliseconds in the very worst case.

The main safety issue would be potential very smallish voltage differences locally.
 
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linuxlad7

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hwl said:
Agreed I really wouldn't expect tripping.

It'll just mean that the earthing isn't as good as you would expect and the time to trip if something does happen could increase by a few milliseconds in the very worst case.

The main safety issue would be potential very smallish voltage differences locally.
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was any wonderwork done by the swiss (F&F??)??
 
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hwl

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linuxlad7 said:
any wonderwork by the swiss (F&F??)??
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Probably an off the shelf earth point product that was bought byt hte contractors - the issues are at the brickwork/mortar end of things rather than any actual OHLE issues.

The domestic equivalent is for those that live in rural areas (e.g. TT earthing) your local earthing copper spike / the nut /crimp fitting on the wire corroding.
 
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hwl

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Mag_seven said:
The milestone was electric trains to Cardiff by Deecmber 2019. Is this another slippage?
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In the style of Roger Ford: They didn't specify Gregorian or Julian calendar.

The Christmas hols period was included the time for works so by end would have been cleared?
 
Chris125

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linuxlad7 said:
Noel Dolphin is from Furrer and Frey I gather, ..so probably good source and good news
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Indeed he is, he's since tweeted a bit more info about how they've 'minimised' the issues: https://twitter.com/NoelDolphin/status/1188437857549062145

"Mainly by removing copper contact wire and using aluminium contact wire. Also fixing some of the leaking drip pans after years of arguing internally in NR."

"Never going to be perfect in those conditions. Will always need more maintenance - as it is almost 100% humidity, permanently in some places. However, most corrosion issues minimised now (would not at this point want to say overcome)"
 
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takno

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Mag_seven said:
Nothing like doing your dirty washing in public is there.
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Presumably there's some mileage to be had in criticizing the bad old (Carne) days, now NR is entering a bright future under dynamic new leadership.
 
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linuxlad7

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Chris125 said:
Indeed he is, he's since tweeted a bit more info about how they've 'minimised' the issues: https://twitter.com/NoelDolphin/status/1188437857549062145

"Mainly by removing copper contact wire and using aluminium contact wire. Also fixing some of the leaking drip pans after years of arguing internally in NR."

"Never going to be perfect in those conditions. Will always need more maintenance - as it is almost 100% humidity, permanently in some places. However, most corrosion issues minimised now (would not at this point want to say overcome)"
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Isnt ally rather chemically active . make yer own battery
Why doesnt the aluminium wire rot even quicker in the steel and/or copper system
 
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GRALISTAIR

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Cu is +0.34 volts vs SHE (Standard Hydrogen Electrode)
Al is -1.66 volts
Iron(steel) is - 0.44 volts

So Copper to Iron/Steel - steel would corrode - steel would be the anode.
Aluminium to Steel - aluminium would corrode and steel would actually be the cathode. I would need the full story before I could comment further. These are just the basics.

Sounds to me they want the aluminium to be sacrificial to protect the steel. Cheaper and more capacity than zinc/galv
 
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hwl

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GRALISTAIR said:
Cu is +0.34 volts vs SHE (Standard Hydrogen Electrode)
Al is -1.66 volts
Iron(steel) is - 0.44 volts

So Copper to Iron/Steel - steel would corrode - steel would be the anode.
Aluminium to Steel - aluminium would corrode and steel would actually be the cathode. I would need the full story before I could comment further. These are just the basics.

Sounds to me they want the aluminium to be sacrificial to protect the steel. Cheaper and more capacity than zinc/galv
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The conductor rail isn't actually a rail as such but rather a continuous wire support for the copper alloy wire, the conductor rail is an aluminium alloy extrusion - probably 6xxx series (6082 at a guess).

6082 is very corrosion resistant compared to pure Al especially if you can keep the pH between 4 - 9. (used for welded boat hulls). Swapping the copper alloy wire to aluminium wire (6082 is wire drawable) cuts out one source of differential metal corrosion.
 
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hwl

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GRALISTAIR said:
I would be shocked if the pH is of this range but of course fresh concrete, cement, grout, gunnite, etc would be above pH 9
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None of it should be in direct contact but you never know what drips of the down from above.

Virtually all of the steel work in the tunnel is stainless rather than galvanised so assuming 316 (which is more electro-positive than mild steel) the 6082 will still slowly corrode where they are in contact.

I do still wonder if the soot layer is still intact enough to be conductive...
 
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ATW158Xpress

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Traction changeover signs are going up just west of Pilning station. Does this mean that IET’s will run on diesel for 5 miles until the M4 bridge west of Severn Tunnel Junction and vice versa?
 
oglord

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ATW158Xpress said:
Traction changeover signs are going up just west of Pilning station. Does this mean that IET’s will run on diesel for 5 miles until the M4 bridge west of Severn Tunnel Junction and vice versa?
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I think they are going to extend electric running as far as Pilning for the time being and then diesel after that until the full electric running to Cardiff. See, for instance, http://charlwoodhouse.co.uk/rail/liverail/train/17126382/16/12/19 which indicates an electric changeover at Pilning, but entirely diesel before that.

Compare this with http://charlwoodhouse.co.uk/rail/liverail/train/16881234/06/01/20 which is diesel from Swansea, changing to electric at Cardiff.
 
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ATW158Xpress

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oglord said:
I think they are going to extend electric running as far as Pilning for the time being and then diesel after that until the full electric running to Cardiff. See, for instance, http://charlwoodhouse.co.uk/rail/liverail/train/17126382/16/12/19 which indicates an electric changeover at Pilning, but entirely diesel before that.

Compare this with http://charlwoodhouse.co.uk/rail/liverail/train/16881234/06/01/20 which is diesel from Swansea, changing to electric at Cardiff.
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Ohh that’s makes sense the question is when we likely to see electric running extended to Severn Tunnel East before Christmas and the full route onto Cardiff for Easter??
 
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ATW158Xpress

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oglord said:
According to the second link, it is full electric from Cardiff on the 6th of January.
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What I read on Network Rail website was wires to be switched on from St Brides to Cardiff during Christmas week and testing to be carried out throughout the winter months.
 
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Linda smith

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Hmmm? I know there's a greater distance involved here. But If it is going to take several months to test and certify the wires from Bristol parkway to Newport. How come it's going to take barely 2 weeks to certify the section from cardiff to Newport ? Surely it would be logical to get the section from Newport up and authorized for traffic sooner rather than later?

But then again, i guess the powers that be want to make a big song & dance from Cardiff, who knows eh?
 
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