Network Rail Overheat

[Mike Storey]

5 hours ago, DY444 said:

 

This article is about the work done over Christmas at Forest Gate:

 

https://www.railengineer.co.uk/2019/01/29/electrification-renewals-at-forest-gate-over-christmas-2018/

 

Penultimate paragraph says it's all done apart from a section at Stratford

 

Many thanks! Shows how out of date I have become! The switch to the GEFF system, approved in 2012 after I left,  is very interesting (and ultimately a move to autotransformers when CrossRail kicks in). It retains the original concept of re-using as much of the original 1949 stanchions as possible, but with additional specifications to the original in-house project, in particular the separation of reliance on multiple spans and the segregation of crossover OLE, in both cases to isolate the effects of damage on the fasts or slows, from the other. Very sensible.

 

I would guess that the remaining work at Stratford, is re-work from the original concept, which was delivered on the basis of Mark 3b slung on to the original posts/crossbars. As Mike SM says, this is now more of a hybrid of Series 1 F&F. This is no longer the low cost, new-for-old scheme that I was familiar with, but something in between!

 

Does anyone know how this stood up to the recent hot weather?

 

 

[Mike Storey]

2 hours ago, caradoc said:

 

And the headline on the BBC News website this morning was on the lines of 'Rail travel problems continue despite temperature falling', as if all the damage should have miraculously repaired itself as soon as it got a bit cooler.

 

 

Not entirely - the report referred to lightning strikes following the heatwave.

[Titan]

1 hour ago, jim.snowdon said:

 

 

Elsewhere, the "howls of protest" about the GWML infrastructure is not to do with the OLE itself, but the structures that hold it up. The contact wire system - the catenary, contact wire and the bits in between - does not "know" whether it is being held up by vintage Mk1 structures or by the GWML's clumsy and overweight structures. 

 

Jim

 

I can assure you it most certainly does "know".  GWML OLE uses much higher tensions in the wires than Mk1 or Mk3. If you tried to string up the same equipment on the old design structures the OLE would just pull them over as they would not be able to take the extra loading.  The higher tensions is what helps it to cope with multiple pantographs at high speed, as well as improving resistance to wind.  Not only that, but you would be unable to terminate the wires on the booms rather than the masts, as they would bend under the loading. This is important as being able to terminate on the booms allows you to avoid crossing wires, so helping to ensure if one wire fails it does not take others down with it.  I can assure you that the new structures are not oversized at all, but is what is required to support the new equipment reliably.

 

The structures are part and parcel of the OLE and the term OLE includes the structures as part of the system. They are designed together as one.

Edited July 26, 2019 by Titan

[Mike Storey]

4 hours ago, multivac said:

Sorry if I was "over the top" with my comments in previous posts.  I would be interested in replies from those in the rail industry in how the UK railways cope with high temperatures and if possible comparing practice to other countries especially Japan.

 

Japan seems to have had its major heatwave, with record temperatures, in May. In Hokkaido, the Northern main island, 40 trains were being cancelled every day, and the rest running under reduced line speed, due to the fear of buckled rails (according to the Straits Times). i.e. much the same as in the UK recently.

[Mike Storey]

4 minutes ago, Titan said:

 

I can assure you it most certainly does "know".  GWML OLE uses much higher tensions in the wires than Mk1 or Mk3. If you tried to string up the same equipment on the old design structures the OLE would just pull them over as they would not be able to take the extra loading.  The higher tensions is what helps it to cope with multiple pantographs at high speed, as well as improving resistance to wind.  Not only that, but you would be unable to terminate the wires on the booms rather than the masts, as they would bend under the loading. This is important as being able to terminate on the booms allows you to avoid crossing wires, so helping to ensure if one wire fails it does not take others down with it.  I can assure you that the new structures are not oversized at all, but is what is required to support the new equipment reliably.

 

The structures are part and parcel of the OLE and the term OLE includes the structures as part of the system. They are designed together as one.

 

Quite so, and having read the Rail Engineer article kindly linked by DY444, about the GE, there would appear to have been few "howls of protest" about the just as unsightly, 1949 structures being re-used for the F&F designed hybrid, auto-tensioned replacement catenary that has mostly now been installed (as opposed to the original Mark 3 based string that had started the scheme). Perhaps folk in the Chilterns are a little more sensitive, or perhaps there are fewer views to be spoiled by gurt great steel beams in Essex? Either way, neither group appears to be moaning to the meeja about their trains being cancelled due to heat.

 

[jim.snowdon]

12 minutes ago, Titan said:

 

I can assure you it most certainly does "know".  GWML OLE uses much higher tensions in the wires than Mk1 or Mk3. If you tried to string up the same equipment on the old design structures the OLE would just pull them over as they would not be able to take the extra loading.  The higher tensions is what helps it to cope with multiple pantographs at high speed, as well as improving resistance to wind.  Not only that, but you would be unable to terminate the wires on the booms rather than the masts, as they would bend under the loading. This is important as being able to terminate on the booms allows you to avoid crossing wires, so helping to ensure if one wire fails it does not take others down with it.  I can assure you that the new structures are not oversized at all, but is what is required to support the new equipment reliably.

 

The structures are part and parcel of the OLE and the term OLE includes the structures as part of the system. They are designed together as one.

I'll disagree, at least up to a point. If a structure is strong enough to take the applied loads, but you substitute it with something several times stronger, it won't make any significant difference to what is attached to it.

 

Jim

[Titan]

8 minutes ago, jim.snowdon said:

I'll disagree, at least up to a point. If a structure is strong enough to take the applied loads, but you substitute it with something several times stronger, it won't make any significant difference to what is attached to it.

 

Jim

 

But the whole point is that the previous designs are not strong enough as the new applied loads are too high for them, necessitating something much stronger. Therefore it does make a significant difference.

Edited July 26, 2019 by Titan

[jim.snowdon]

1 hour ago, Titan said:

 

But the whole point is that the previous designs are not strong enough as the new applied loads are too high for them, necessitating something much stronger. Therefore it does make a significant difference.

We're looking at this through opposite ends of the telescope, and not going to resolve it on here.

 

Jim

[Titan]

5 minutes ago, jim.snowdon said:

We're looking at this through opposite ends of the telescope, and not going to resolve it on here.

 

Jim

 

I am not looking through any telescope. I design the stuff for a living, so know exactly what I am talking about. What i find particularly ironic was some structures were found to have inadequate strength, and had to be redesigned.  In other words they were made too small and under engineered for the required loads.

Edited July 26, 2019 by Titan

[jim.snowdon]

And I work for that part of the client organisation for which you design.

 

We're still going to resolve it on here.

[Titan]

6 minutes ago, jim.snowdon said:

And I work for that part of the client organisation for which you design.

 

We're still going to resolve it on here.

 

Many people work for Network Rail. Does not make everyone who works for Network Rail an OLE professional, let alone qualified to undertake design.

Edited July 26, 2019 by Titan

[jim.snowdon]

Shh! I've closed the argument.

 

If our paths cross in MK, you can continue the debate then.

[Titan]

I think the word you are looking for is lost...

[roythebus]

Why don't you two go down the pub and sort it out over a few pints?  good old-fashioned railway method of solving problems.

 

[Mark Saunders]

1 hour ago, roythebus said:

Why don't you two go down the pub and sort it out over a few pints?  good old-fashioned railway method of solving problems.

 

 

Did that yesterday and then went to York Station to find a train home amid the chaos!

 

Mark Saunders

[jim.snowdon]

9 hours ago, roythebus said:

Why don't you two go down the pub and sort it out over a few pints?  good old-fashioned railway method of solving problems.

 

Agree totally. It's why I put a stop to the argument.

[caradoc]

14 hours ago, Mike Storey said:

 

Not entirely - the report referred to lightning strikes following the heatwave.

 

OK, but I was referring to the headline, and in particular the use of the word 'despite'.

[multivac]

13 hours ago, Mike Storey said:

 

Japan seems to have had its major heatwave, with record temperatures, in May. In Hokkaido, the Northern main island, 40 trains were being cancelled every day, and the rest running under reduced line speed, due to the fear of buckled rails (according to the Straits Times). i.e. much the same as in the UK recently.

 

Talk about temperature ranges nearly 40C in Hokkaido in May and about -4C in January. Does anyone know how the Hokkaido Shinkansen  lines and the other purpose built Shinkansen  lines, cope with wide temperature differences or could point me toward something on the Web?

 

Not wishing to inflame the debate regarding OHE again, to "weather proof" and to improve general reliability would major investment be required (especially on ECML) on the OHE infrastructure? 

 

[The Stationmaster]

14 hours ago, Mike Storey said:

 

Quite so, and having read the Rail Engineer article kindly linked by DY444, about the GE, there would appear to have been few "howls of protest" about the just as unsightly, 1949 structures being re-used for the F&F designed hybrid, auto-tensioned replacement catenary that has mostly now been installed (as opposed to the original Mark 3 based string that had started the scheme). Perhaps folk in the Chilterns are a little more sensitive, or perhaps there are fewer views to be spoiled by gurt great steel beams in Essex? Either way, neither group appears to be moaning to the meeja about their trains being cancelled due to heat.

 

The GEML is now a fascinating mixture of structures and fittings.  Quite a lot of the original dc structures remain - but some have been replaced over the years of course - then there are the assorted styles of masts (in particular) that came with the ac electrification schemes and extension of them.  To these have been added at least two (to my eyes) more recent styles of register arms with the incredibly simple Series 1 version nowadays visible on structures anything between at least 70 years old and those dating from the late 1950s/early '60s.

 

So to answer Jim's comment - yes - there are now Series 1 register arms on lighter older masts and on even older massively constructed dc era gantries.  But compared with the GWML the GEML does not at present happen to have any trains with two pantographs 10 vehicle lengths apart running at 125 mph and tensioned accordingly.  Not surprising perhaps that Class 387s which have had no problems on earlier oh electrification ran into pantograph carbon wear problems on the GWML (now solved - presumably the next stage will be dealing with 319/769 units to also take account of GWML overhead? - but that won't be until next year probably).

[Ron Ron Ron]

The high temperatures have caused problems with rail travel across Europe.....

 

https://www.swissinfo.ch/eng/track-record_swiss-railway-tracks-buckle-under-the-heat/45120350

 

From Germany's DW News....

"While commuters and holiday travelers lucky enough to board a train with a functioning air conditioning system (not a given even in a supposedly high-tech country such as Germany) may have found some respite, their sunny demeanor could quickly turn cloudy once they discover that they are stranded on the trains because they can't actually move.

The high temperatures can cause points failures and signal disturbances, while in some places the tracks have buckled under the heat.

 

A spokeswoman for Germany's rail company Deutsche Bahn said on Wednesday that "our technology has reached its limits in these extreme temperatures."

Indeed, a number of trains were canceled or delayed in western Germany this week".

 

 

[ess1uk]

It could have been a whole lot worse.

 

however this extreme weather is the new norm so better start making changes to get use to it