GWML Electification

[Geoff Endacott]

The masts on the GWML need to be closer together than those on the Continent otherwise the residents of Goring might not notice them.

 

Geoff Endacott

[NIK]

I believe that the main reason is that the GWML has to be set up for relatively closely spaced pantographs on 387's and 5 car 800's. These create lots more problems for the designers than either an 18 car Eurostar or 2 TGV's coupled up where the pantographs are much further apart. The resultant forces demand a much higher tension and consequently beefier structures.

 

Jamie

 

Hi Jamie,

 

But is not the GWML line speed much lower than HS1 or TGV lines?. Or have the lines including Reading to Newbury been designed for 140mph and 140 mph is near enough 186+ to require large metal supports?.

 

Does HS1 has to cope with pairs of Javelins or do Javelins have pantographs both ends like I assume all TGV units do?.

 

 

Regards

 

Nick

[Zomboid]

There's other factors, mostly derived from the functional specification. Issues like wind load will have a big impact.

 

I've no idea what it's specified to do in comparison to the French LGVs, but it is different because it is answering a different question.

[Mike Storey]

It is also a fact that the vast majority of LGV infrastructure utilises single structures on double track lines, on a tension system, much like BR Mark 3, whereas, apart from East of Slough (good name for a film anyone?), much of the new F&F design involves fixed portal beams over 3 or 4 tracks. The remit was to maximise resistance to vertical and lateral forces, including wind as well as those expressed by pantos in multiple, but also to minimise effect when de-wirements occur (the major problem with Mark 3 multiple track, wire suspended arrangements, as the ECML have been finding out for the past 30 years).

 

I guess the issue is also whether such enormous stanchions are needed for the simpler, single or double track sections, further West. Dunno, but from pics so far seen, they are not that bad, are they?

 

If you want to find visually intrusive spaghetti, giant aerial transformers and overkill on bridge parapets and sound barriers, on LGV routes, it's not difficult. Just drive along the autoroute next to Poitiers, or Tours. It should also be noted that, apart from a standardisation of trains using LGV dedicated routes, the service frequencies are s0d all, compared to the GWML, apart maybe from Paris-Lyon, and Paris-Lille, but even then.....

[Geoff Endacott]

Issues like wind load will have a big impact.

 

And there's a lot of hot air in Goring. And Steventon.

 

Geoff Endacott

[Fat Controller]

Hi Jamie,

 

But is not the GWML line speed much lower than HS1 or TGV lines?. Or have the lines including Reading to Newbury been designed for 140mph and 140 mph is near enough 186+ to require large metal supports?.

 

Does HS1 has to cope with pairs of Javelins or do Javelins have pantographs both ends like I assume all TGV units do?.

 

 

Regards

 

Nick

HS1 has regular workings of 'Javelins' in multiple, along with the new 'Velaros', which have multiple pantographs throughout the train (normally, it's the ones nearest the ends that are raised) TGVs have pantographs at both ends of a rake, but only one is normally raised during high-speed running; there is a 25kV 'bus' that runs along the roofs of the intermediate trailers. Trains formed of two rakes would have one pantograph raised on each.

[caradoc]

Having been involved in more OLE dewirements than I care to remember (mainly as a Controller but also occasionally as a passenger) I am delighted to see equipment designed to be as robust and reliable as possible, given the nature of OLE.

[Fat Controller]

Having been involved in more OLE dewirements than I care to remember (mainly as a Controller but also occasionally as a passenger) I am delighted to see equipment designed to be as robust and reliable as possible, given the nature of OLE.

Agreed, and with knobs on!. I've no direct experience of 'wires down' as a passenger, but I've had to sort out the operational aspects of the mess as a Controller.

[rodent279]

Hi Jamie,

 

But is not the GWML line speed much lower than HS1 or TGV lines?. Or have the lines including Reading to Newbury been designed for 140mph and 140 mph is near enough 186+ to require large metal supports?.

 

Does HS1 has to cope with pairs of Javelins or do Javelins have pantographs both ends like I assume all TGV units do?.

 

 

Regards

 

Nick

I believe another difference between wiring on "classic" routes such as WCML,ECML, GWML etc and the various LGV's is that the contact wire on an LGV can be kept virtually constant. Because the infrastructure is new, all bridges, tunnels etc can be specified with sufficient clearance. Despite many structures being rebuilt in wiring the classic lines, it's not always possible to keep a constant contact wire height. Edited January 21, 2019 by rodent279

[NIK]

Having been involved in more OLE dewirements than I care to remember (mainly as a Controller but also occasionally as a passenger) I am delighted to see equipment designed to be as robust and reliable as possible, given the nature of OLE.

Hi,

 

I was just worried that the extra metalwork might have been part of the governments decision to cut back on electrification.

 

I guess dewirements are a major problem for the UK with its patchwork of 25kV electrified routes, rationalised mainlines and few diesel locomotives.

 

 

Regards

 

Nick

[The Stationmaster]

It might help to say what is where.  The quadruple track section of the GWML between part of the distance between Steventon and Didcot and then east of Foxhall Jcn (just west of Didcot station) is mainly portal structures where nothing else is possible but there are some single  line structures in places where track spacing allows and a considerable number of double line cantilever/bracketed structures where topography allows.   The B&H line through both the diveunder ('Feeder Line') and original B&H  connection from Westbury Line Jcn at Reading to Suthcote Jcn is a mixture of double line and single line structures with a number of the double line structures looking little different from (although a good deal sturdier than) similar structures installed on the WCML.  

 

The rest of the B&H beyond Souhcote Jcn and the double line sections west of Steventon is a mixture of predominantly double line and single line structures with some portal structures to carry the ohle tensioning units (and I think the anchor units as well).   Overall there is now a considerable mileage of single line structures on various bits of the GWML although in many cases the masts are more substantial than used on earlier BR single line structures.

 

Thus Twyford station (the left hand picture) is a mixture of portals (due to platform width) and cantilever/bracketed structures and you can also see the simplicity of the method of attaching the wires to the registration arm and the registration arm to the structure.  While the west of end of Goring in the other photo  - still awaiting wiring when I took this picture - is full width portal structures on the station side of the pverbridge

 

Alas the photos won't now attach due to RMweb taking it's time and they deleted themselves.  I will try again later or tomorrow then  added themselves!!!  not sure if they will enlarge.

Edited January 21, 2019 by The Stationmaster

[jim.snowdon]

Having been involved in more OLE dewirements than I care to remember (mainly as a Controller but also occasionally as a passenger) I am delighted to see equipment designed to be as robust and reliable as possible, given the nature of OLE.

Nobody wants to see dewirements happen, but they are rarely due to the supporting structures. Making them more robust has negligible effect once they have passed the point of being robust enough to hold up the wiring.

 

Jim

[jim.snowdon]

There's other factors, mostly derived from the functional specification. Issues like wind load will have a big impact.

 

I've no idea what it's specified to do in comparison to the French LGVs, but it is different because it is answering a different question.

I think you would find that the wind load on the structures themselves is greater than that on the wiring that they are holding up. And that's just simple catenary - there are older originally DC systems where lighter structures are holding up heavier compound catenary.

 

Jim

[Mike Storey]

I think you would find that the wind load on the structures themselves is greater than that on the wiring that they are holding up. And that's just simple catenary - there are older originally DC systems where lighter structures are holding up heavier compound catenary.

 

Jim

 

Not sure where you are coming from on this Jim? All our research on the ECML de-wirement problems in the late 90's and early 2000's, showed that the gusting wind forces on Mark 3b arrangements were very major contributors to de-wirements. We only found this out by introducing anemometers at the sections which we suspected were most affected. This led to increasing the frequency of supporting masts in the worst affected stretches, which was not a minor piece of work, but it did allow wind-caused dewirements to reduce by around 40% over a five year period. But it remained true that if forecast average wind speed exceeded certain maxima, then train speed reduction also delivered huge benefits compared to no action.

 

You are correct in that probably a large minority, if not majority, of all de-wirements, across all UK OLE, has been due to faults on loco and EMU pantos (or on track relaying outside permitted geometry in a few cases), but even if that is so, it is the consequence of the de-wirement that is significant. With Mark 3 arrangements, where tensioned wire-spans are used, the consequences are usually horrendous in terms of numbers of tracks and distances affected. With rigid portal structures, such consequences are far less extensive.

[rodent279]

Coming past Reading just now (1130am), I noticed a 319 in the emu sidings. Anyone know why?

[The Stationmaster]

33 minutes ago, rodent279 said:

Coming past Reading just now (1130am), I noticed a 319 in the emu sidings. Anyone know why?

There were two there last week.  I presume they are stored pending conversion if they have gone off lease elsewhere or they might be for artisan familarisation?

[tomparryharry]

3rd rail is the way forward...

 

Ok, back in my cupboard now.

 

Ian.

[NIK]

Hi,

 

Just west of Woolhampon on the Reading Newbury section I saw 4-car EMUs sparking away on a very frosty morning (Thursday) last week as well as IEP 5 car twins sets sparking on the overhead wire. The IEPs had the pantographs up only on the extreme ends.

 

On this section of line the metal arm that connects the insulator pot to the contact wire seems to be about three inches deep and has holes punched in it presumably to reduce wind resistance (and weight?).

 

Regards

 

Nick

[St. Simon]

10 hours ago, rodent279 said:

Coming past Reading just now (1130am), I noticed a 319 in the emu sidings. Anyone know why?

 

9 hours ago, The Stationmaster said:

There were two there last week.  I presume they are stored pending conversion if they have gone off lease elsewhere or they might be for artisan familarisation?

 

Both are still there, they've been there for several weeks, and not that long ago (may be a couple of months) another two (I assume the latest ones are different units) were also at the depot.

 

The best story that seems to connect the two bouts of southern intrusion (not that I'm complaining about it, it gives me something to look at on the commute to / from Tilehurst) is that they are using the wheel lathe at Reading, which isn't that old.

 

8 hours ago, tomparryharry said:

3rd rail is the way forward...

 

Ok, back in my cupboard now.

 

Ian.

 

I still think it might solve the Steventon Problem, but when I suggested it at a meeting of big wigs on the project, they gave me some funny looks as if to say "you stupid boy!".

 

Simon

Edited February 6, 2019 by St. Simon

[Zomboid]

A 3rd rail system like the southern wouldn't fly, but some kind of shrouded bottom contact system (like the DLR) might be justifiable, if the trains weren't already in service without any such equipment.

 

Would be more useful in Bath than for Steventon though. For that one the obvious answer is to just pan down and coast through if you're going fast, or leave the pan up if you're going at whatever speed the OLE allows.

[Banger Blue]

There are currently 2 Class 319s at Reading TCD (319440 & 449 IIRC). We should have another two by the end of the month.

Apart from taking up space they are there for staff / driver training prior to the arrival of the Class 769 “Tri-Modes” (replacing Turbos on the North Downs, Basingstokes and possibly one of the Branch Lines!)

[Arun Sharma]

13 hours ago, Lecorbusier said:

My contribution to the model shop reminiscences would be the excellent Slaters shop of yore in Matlock Bath ... prior to their move to Darley Dale. In truth I don't actually know how good this shop was because I was still a teenager at the time and so perhaps lacked a discerning eye ... but my memories are certainly rose tinted.

 

The only other 'proper' model shop I frequented was the one on the Headington roundabout in Oxford during my University days ... again this seemed pretty good .. If I recall correctly it was called 'Motor Books of Oxford'.

 

It would be interesting to know if I am indeed suffering from a 'rose tinted view' or if these shops would be deemed to pass muster.

Earlier in its life, I believe the shop was the HQ of the Oxford Publishing Company and then later taken over by Motor Books who were based just behind St Martins Lane in London  [+ a couple of subsid. branches in Swindon and Bournmouth]. It was a seriously impressive bookshop with knowledgeable staff - I always got the impression that they were 0gauge modellers rather than RTR suppliers. But a great loss to Oxford though Howes still had a shop in Broad Street in central Oxford at that time.

[jamie92208]

There is an interesting Letter to the Editor in the new Modern Railways.   It is from someone who obviously lives on the south side of the line at Steventon.  He suggests upgrading a track that runs alongside the line so that people can get to the bridge easily and then closing the level crossings.   I don't think he'll be popular with his neighbours....

 

Jamie

[The Stationmaster]

2 hours ago, jamie92208 said:

There is an interesting Letter to the Editor in the new Modern Railways.   It is from someone who obviously lives on the south side of the line at Steventon.  He suggests upgrading a track that runs alongside the line so that people can get to the bridge easily and then closing the level crossings.   I don't think he'll be popular with his neighbours....

 

Jamie

Maybe a better idea would be to close the bridge and keep the level crossings?      The present performance is an utter nonsense and one day somebody is going to forget what they are supposed to do (notwithstanding the auto arrangement for some trains)  and the results might be interesting if not necessarily spectacular or dangerous.  It really is utterly ludicrous in this day and age that a major rail route which is newly, and eventually, being electrified should have to be worked in what amounts to a totally ridiculous manner all because Brunel signed a drawing and some idiot thinks that means he built the bridge with his own hands to his own design.  

[Joseph_Pestell]

2 hours ago, jamie92208 said:

There is an interesting Letter to the Editor in the new Modern Railways.   It is from someone who obviously lives on the south side of the line at Steventon.  He suggests upgrading a track that runs alongside the line so that people can get to the bridge easily and then closing the level crossings.   I don't think he'll be popular with his neighbours....

 

Jamie

 

I used to use that track a lot, almost daily. It's called Station Lane and I used to get very dirty looks from the allotment holders when driving along it as a short cut to properties south of the railway. Saved me a lot of time.

 

Not sure of its current status, but in GW days it was railway owned.

 

I think that you are right that people there would not like it as a solution to the problem but it is probably the best option.