Great Western Electrification Progress

HowardGWR · 12 Feb 2020

Hellzapoppin said:
The main blockade for BRISTOL East is 2021. A lot of enabling works is underway with some of the relaying works around Dr Days junction happening April May this year.

Is it possible, in a short para, to summarize what is faulty with the present layout, that would be solved by this prerequisite project? AIUI, trains going south beyond Bristol need at some point to cross over to westerly platforms or lines, while London trains via Bath, starting from Bristol and ending there, need to keep to the easterly platforms (in and out) while trains reversing in Bristol, such as Cardiff to Portsmouth or Malvern to Weymouth, need to keep to the middle ones. Trains for the north and the Badminton line to London need to be on the westerly side as well.

But it was ever so, even in the thirties, so why is the old eastern layout fundamentally inadequate?

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swt_passenger · 12 Feb 2020

HowardGWR said:
Is it possible, in a short para, to summarize what is faulty with the present layout, that would be solved by this prerequisite project? AIUI, trains going south beyond Bristol need at some point to cross over to westerly platforms or lines, while London trains via Bath, starting from Bristol and ending there, need to keep to the easterly platforms (in and out) while trains reversing in Bristol, such as Cardiff to Portsmouth or Malvern to Weymouth, need to keep to the middle ones. Trains for the north and the Badminton line to London need to be on the westerly side as well.

But it was ever so, even in the thirties, so why is the old eastern layout fundamentally inadequate?

What they put in the last CP5 enhancements update, my bold. :

Network Rail’s obligation
The limited operational flexibility of the junction is seen as a constraint to growth and it is recognised that layout improvements, to allow all lines to reach all platforms at Bristol Temple Meads, will be required.
This project will deliver an enhanced renewal providing the optimum layout which can accommodate the growth in services and provide improved operability, maintainability, reliability and accessibility. The project will also be delivered ahead of electrification in CP6 to avoid the long term commercial, maintenance and renewal risks arising from the electrification of the existing non-standard junction layout.
Scope of works
Reduction of existing 58 point ends to 47 point ends
Minor civils; waterproofing of Avon Street and structure deck replacement HV cable diversion – runs under two tracks on the up side
Junction lighting – for safer maintenance activities
Inclusion of a new transformer due to increased power usage
Demolition of lineside buildings
All associated signalling works inclusive of a data change (79 SEUs)
Minor telecoms works
Signalling gantry renewal (electrification scope)

There may be more in the last Western route study. Not much detail though, just an explanation that’s its needed to reduce conflicts in future timetables. All a bit vague really...

Dai Corner · 12 Feb 2020

swt_passenger said:
What they put in the last CP5 enhancements update, my bold. :

There may be more in the last Western route study, I’ll have a look.

The only moves I don't think are possible at the moment are Platforms 13 and 15 to/from the Filton lines. Pretty sure I've done everything else at one time or another.

HowardGWR · 12 Feb 2020

Dai Corner said:
The only moves I don't think are possible at the moment are Platforms 13 and 15 to/from the Filton lines. Pretty sure I've done everything else at one time or another.

If that's the essence, then this project should be called "1935 improvement reinstatement" it would seem. I have the track layout history in R.A.Cooke's excellent series (Section 19A if you are interested) and this shews that the 1974 rationalisation took that capability away. It had been an impressive array of switches and crossings that was installed along with the power Bristol East power signal box in 1935. A train could indeed cross directly from the Midland junction right over to the furthest line on the southern side, and any line in between.
So they would just be repairing the damage to flexibility inflicted 45 years ago, if so. Yes it saved some maintenance I suppose over that long period.

JeffH16 · 13 Feb 2020

Dai Corner said:
The only moves I don't think are possible at the moment are Platforms 13 and 15 to/from the Filton lines. Pretty sure I've done everything else at one time or another.

Until about 1 month ago I was a TVSC Bristol Signaller, you can currently go to/from any platform to any line in the current layout. The main change with the bristol east upgrade is that there will be 6 running lines through throughout as opposed to 5 and a siding.

Dai Corner · 13 Feb 2020

JeffH16 said:
Until about 1 month ago I was a TVSC Bristol Signaller, you can currently go to/from any platform to any line in the current layout. The main change with the bristol east upgrade is that there will be 6 running lines through throughout as opposed to 5 and a siding.

Thanks for the correction.

HowardGWR · 13 Feb 2020

JeffH16 said:
Until about 1 month ago I was a TVSC Bristol Signaller, you can currently go to/from any platform to any line in the current layout. The main change with the bristol east upgrade is that there will be 6 running lines through throughout as opposed to 5 and a siding.

Summarised neatly in one paragraph, as I requested earlier, many thanks.

swt_passenger · 13 Feb 2020

HowardGWR said:
Summarised neatly in one paragraph, as I requested earlier, many thanks.

Also goes to show how vague NR information is. The paragraph I quoted clearly suggested different...

Dai Corner · 13 Feb 2020

swt_passenger said:
Also goes to show how vague NR information is. The paragraph I quoted clearly suggested different...

The only thing I can think of is access for platforms 13/15 from the West. But that's outside the scope of any work at Bristol East Junction (and this thread!).

Jurassicjewel · 16 Feb 2020

Does anyone know when trains will use the Severn tunnel on electric as on Thursday 13Feb the class 800 switched to Diesel at Bristol Parkway and at Newport was on Electric to Cardiff. Interestingly on approaching Cardiff switched to Diesel where it terminated. On the return it was Electric from Cardiff then I think Diesel under the tunnel and back on the juice at Bristol Parkway.

swt_passenger · 16 Feb 2020

Jurassicjewel said:
Does anyone know when trains will use the Severn tunnel on electric as on Thursday 13Feb the class 800 switched to Diesel at Bristol Parkway and at Newport was on Electric to Cardiff. Interestingly on approaching Cardiff switched to Diesel where it terminated. On the return it was Electric from Cardiff then I think Diesel under the tunnel and back on the juice at Bristol Parkway.

I suspect posts made about #9691 onwards, a few weeks ago, are still roughly the latest position. So within a few weeks from now, perhaps...

edwin_m · 16 Feb 2020

Don't think it's been posted on here yet, but Rail Engineer print edition is saying that the problems in the Tunnel are due to anaerobic bacteria eating the oxide coating which normally forms on aluminium and prevents further corrosion. This means they are corroding continuously and also worsens the electrolytic corrosion when in contact with the copper wire (now replaced by more aluminum).

swt_passenger · 16 Feb 2020

edwin_m said:
Don't think it's been posted on here yet, but Rail Engineer print edition is saying that the problems in the Tunnel are due to anaerobic bacteria eating the oxide coating which normally forms on aluminium and prevents further corrosion. This means they are corroding continuously and also worsens the electrolytic corrosion when in contact with the copper wire (now replaced by more aluminum).

Was posted a little while ago, post #9714. Didn’t really result in any discussion though.

Optom1 · 16 Feb 2020

Network rail have weedkilling trains,maybe upward spraying Chlorhexidine solution trains could keep the catenary rail in the tunnel bacteria free?I doubt it!

mr_jrt · 16 Feb 2020

Unfortunately, being a living organism all spraying them with antibiotics will do is make them resistant. Surely there's something they could line the tunnel with to make it water-tight? Plastic-based coating of some sort, perhaps?

GRALISTAIR · 16 Feb 2020

mr_jrt said:
Surely there's something they could line the tunnel with to make it water-tight? Plastic-based coating of some sort, perhaps?

One of the solutions on test at the moment in a different location. Spray on a polyurea elastomer coating. It is an insulator too. Not sure what the breakdown voltage is but fairly high.

Optom1 · 16 Feb 2020

Thanks Gralistair,it shows a lot of thinking outside the box is being done.As an aside ,solutions like chlorhexidine are only bacteriocidal,that is they only inhibit growth,not kill,maybe enough,again I doubt it

McRhu · 16 Feb 2020

Never mind the catenary! What if this rapacious aluminium-devouring bacteria escapes the tunnel and goes on a world wide rampage, chomping its way through said metal on a global scale? There'd be scarcely a coke can, crutch, aircraft, Type 45 Destroyer, pie dish, Audi A8 or golf club left by the end of the year. It's bloody Quatermass and the Severn Tunnel (or was it Doomwatch?). Anyway: you get the gist. Seal it off before it's too late!

GRALISTAIR · 16 Feb 2020

McRhu said:
Never mind the catenary! What if this rapacious aluminium-devouring bacteria escapes the tunnel and goes on a world wide rampage, chomping its way through said metal on a global scale? There'd be scarcely a coke can, crutch, aircraft, Type 45 Destroyer, pie dish, Audi A8 or golf club left by the end of the year. It's bloody Quatermass and the Severn Tunnel (or was it Doomwatch?). Anyway: you get the gist. Seal it off before it's too late!

The bacteria is anaerobic apparently. You would be surprised at what bacteria can do. When I did my MSc and DIC in Corrosion of Engineering Materials at Imperial College London there was a whole module plus assignment plus lab write ups and exam question on Bacterial and microbial corrosion. There is one nasty little blighter called desulphodivibrio desulphuricans. Survives in very aggressive conditions. Each environment is different and Severn Tunnel on the GWML is one of those.

Merthyr Imp · 16 Feb 2020

This somehow reminds me of the problems with the rats said to be eating the grease sealing the flap on the tubes of the Atmospheric Railway.

If Brunel was around today one can imagine him giving a wry smile.

Sean Emmett · 16 Feb 2020

Dai Corner said:
The only thing I can think of is access for platforms 13/15 from the West. But that's outside the scope of any work at Bristol East Junction (and this thread!).

It is possible to reach P15 (and the down through) direct from the West. Done that. P13 is a bit more tricky due to the buffer stop.

Glad to see Bristol East Jn getting a nudge forward with 6 running lines.

Disappointed that plans for P1/0 in the Digby Wyatt train shed have been scaled back. What capacity will the revised plaforms P1/0 have, if the ever get built. A 4 car voyager can just be squeezed into P1 at the mo.

Big question is whether electrification will ever reach Bristol? (Centre that is, as opposed to Parkway which is of course in South Glos).

mr_jrt · 16 Feb 2020

Does anyone know what the bacteria in the tunnel causing the problem is called? They're usually pretty specific about what they can digest given how simple they are, I would have thought. There must be other options, from coating all the aluminium in something else it won't be able to consume, to just not using aluminium at all in there...?

...though that said, there can't be much aluminium naturally in that area so it seems unlikely they would survive there very long if they could only consume aluminium oxides...

Don't know if this is of interest to anyone, may shed some light if you're so inclined:
https://www.intechopen.com/books/al...d-corrosion-in-aluminium-alloys-7075-and-2024

Phlip · 17 Feb 2020

mr_jrt said:
Unfortunately, being a living organism all spraying them with antibiotics will do is make them resistant.

Chlorohexidine is a disinfectant, not an antibiotic, so resistance wouldn't be a problem. But it is corrosive, would need reapplying very regularly and would not be kind to the wider environment (indeed, any associated release of chlorine gas would be toxic).

Phil. (Microbiologist)

mr_jrt · 17 Feb 2020

Thanks for the correction! Can bacteria not become resistant to disinfectants?

hwl · 17 Feb 2020

Chlorine (in many disinfectants as well as sea water) is a very bad idea near aluminium alloys as it speeds up fatigue crack growth as well as corrosion (if the oxide layer is damaged).

swt_passenger · 17 Feb 2020

How about some sort of sacrificial aluminium features, say a few larger plates for a significant area, or does the number of bacteria just increase proportionally?

(Not my area of expertise at all, if that seems a stupid question...)

GRALISTAIR · 17 Feb 2020

Aluminium and alloys are actually used as sacrificial anodes on North Sea oil rig legs. Very light weight and very high capacity. I would derive it from first principles for you but that probably is a little bit too off topic.

There will be an engineering solution to the whole thing don't worry. Just hope it does not take too many possessions.

R G NOW. · 17 Feb 2020

JeffH16 said:
Until about 1 month ago I was a TVSC Bristol Signaller, you can currently go to/from any platform to any line in the current layout. The main change with the bristol east upgrade is that there will be 6 running lines through throughout as opposed to 5 and a siding.

So I am thinking it is the line from platforms 1 and 3 that is to be made a complete run then. On the Opentraintimes map it seems to have a siding in line with it. So I assume they will make this the 6th line ready for electrification and no alterations to signalling would be needed other then a route indicator showing DR on the signals from p1 - 3 plus an extra signal numbered BL2068.Lastly a slight alteration to the tracks as well.

Peter Sarf · 17 Feb 2020

Is this Aluminium Oxide vs bacteria problem going to occur in other railway (tunnel) applications or is it just that the Severn Tunnel is very damp ?.

GRALISTAIR said:
Aluminium and alloys are actually used as sacrificial anodes on North Sea oil rig legs. Very light weight and very high capacity. I would derive it from first principles for you but that probably is a little bit too off topic.

There will be an engineering solution to the whole thing don't worry. Just hope it does not take too many possessions.

For the tunnel they could fit engines to the coaches and..... I'll get my coat

.

Seriously though. Could enough be done to make the bacteria extinct in the tunnel or is re-introduction too likely ?.

I was also pondering that, in steam days, the sulphur etc in the smoke might well kill the bacteria ?. But then there would not have been any aluminium to worry about anyway.

mr_jrt said:
........ I would have thought. There must be other options, from coating all the aluminium in something else it won't be able to consume, to just not using aluminium at all in there...?

Risk is that the coating would interfere with the electrical conductivity required. Or is there a copper bit attached to the lower edge of the rail.

R G NOW. · 17 Feb 2020

Peter Sarf said:
Is this Aluminium Oxide vs bacteria problem going to occur in other railway (tunnel) applications or is it just that the Severn Tunnel is very damp ?.

For the tunnel they could fit engines to the coaches and..... I'll get my coat .

Seriously though. Could enough be done to make the bacteria extinct in the tunnel or is re-introduction too likely ?.

I was also pondering that, in steam days, the sulphur etc in the smoke might well kill the bacteria ?. But then there would not have been any aluminium to worry about anyway.

Risk is that the coating would interfere with the electrical conductivity required. Or is there a copper bit attached to the lower edge of the rail.

Would chrome plating sort it?. just a thought. There is a very salty atmosphere in the tunnel as I was told years ago, even the rails rust very quickly which is why axle counters were installed many years ago.

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