GWML Electification

[caradoc]

No, it's because there's a danger of the sparks frightening the horses that will be used to haul the trains through the dead section at Steventon.

 

I bet they're regretting having demolished the provender store at Didcot now !

[jim.snowdon]

It could still be done, albeit not necessarily an elegant engineering solution, with measuring track circuits but that would be more complicated.   Is the existing sub aspect approach released I wonder - I would have thought that it would be?

There's nothing in principle to prevent axlecounters being used to emulate treadles, or as timing devices.

 

Jim

[jim.snowdon]

Agree with Jim; happens every few minutes at Drayton Park on the Moorgate branch too..

 

Wonder if it's to do with Didcot having two different types of unit putting up their pans, whereas Farringdon et al is just the one type. Dunno really..........

The contact wire isn't aware of what sort of pantographs are under it in this context, only that a set of carbons comes up from below and bumps into it. The clever stuff with pantographs and the OLE relates to the dynamics at high speeds, and in particular how the second pantograph copes with being in the wake of the first. Unlike conductor rail, the OLE is very bouncy, especially as there is no vertical damping to control the oscillations.

 

Jim

[Arun Sharma]

Jim - If there is no damping, does that mean you can get standing waves set up in the OHLE wires?

Edited March 3, 2018 by ted675

[jim.snowdon]

Jim - If there is no damping, does that mean you can get standing waves set up in the OHLE wires?

Technically, yes, but only if you kept the input vibration stationary and all the span lengths were equal. The reality is much more complex, as the waves set up by the moving pantographs travel along the contact wire and reflect back off discontinuities such as section insulators, anchor points and so on.

 

Jim

[olivegreen]

Technically, yes, but only if you kept the input vibration stationary and all the span lengths were equal. The reality is much more complex, as the waves set up by the moving pantographs travel along the contact wire and reflect back off discontinuities such as section insulators, anchor points and so on.

 

Jim

 

There are some interesting videos on these issues on youtube, showing how they are set up and the effect on a following pantograph; a number of them made by the French/SNCF in research for their high-speed lines.

[Pandora]

There are some interesting videos on these issues on youtube, showing how they are set up and the effect on a following pantograph; a number of them made by the French/SNCF in research for their high-speed lines.

There is a device known as  the Dogbone or Stockbridge Damper  used on overhead power lines to suppress unwanted oscillation of the line, ( the National Grid). Do they install such dampers on railway  25kV contact wires?

 

https://en.wikipedia.org/wiki/Stockbridge_damper

Edited March 3, 2018 by Pandora

[jim.snowdon]

There is a device known as  the Dogbone or Stockbridge Damper  used on overhead power lines to suppress unwanted oscillation of the line, ( the National Grid). Do they install such dampers on railway  25kV contact wires?

 

https://en.wikipedia.org/wiki/Stockbridge_damper

There is, and I am puzzled as to why no-one seems to have either tried them or investigated further.

 

Jim

[The Stationmaster]

Jim - If there is no damping, does that mean you can get standing waves set up in the OHLE wires?

 

Yes,  it was why Eurostar speeds on the ECML was constrained.  during test there was found to be vertical movement of the contact wire by as much as 6 inches either side of centre following the passage of the leading pantograph at 125mph. if the rear pan had been raised it would most likely have resulted in a dewirement.  Class 373 Eurostars are exceptional because of their high (by British standards) pantograph uplift forces and the UK pan had to be redesigned in order to reduce the uplift force.

[caradoc]

On a visit to Swindon today, noted that gantries/masts are now in place through the station, although very few fixings and certainly no wires ! Also had a quick trip on GW Class 387s from Didcot to Cholsey and back, the route diagrams above the doors show Paddington-Didcot plus Reading-Newbury; Obviously Oxford is as far away from seeing electric trains as ever.

[Northroader]

Actually I was looking at the Swindon Didcot stretch today, and thought the wiring is coming along well. The catenary and contact are done on both lines as far as the old Highworth Junction site at Swindon, excepting a stretch on the down at Bourton, and two stretches on the up at Uffington and Shrivenham. The auto transformer cable is behind with progress, gaps here and there, and there are bits of blue rope visible in places. This excludes the Steventon gap, on this stretch the masts, crossbeams, brackets, and insulators are all positioned, and there is a bit of earth cable, but no overhead wires at whatever height. On the Oxford line nothing more has happened for ages.

[uax6]

Technically, yes, but only if you kept the input vibration stationary and all the span lengths were equal. The reality is much more complex, as the waves set up by the moving pantographs travel along the contact wire and reflect back off discontinuities such as section insulators, anchor points and so on.

 

Jim

 

Also ground conditions play a part too. Being up on the Fens here, I can often watch a heavily loaded sand train go past the box, and then for some minutes watch the overhead bounce. This is due to stanchions moving with their concrete bases as the train goes by (the box moves a bit too!).  

 

As an aside, while they were pouring the bases for the electrification up here, one hole swallowed a whole train of concrete, (at least two big mixers worth, so about 20 tons) and still there was no evidence of it in the hole....

 

Andy G

Edited March 10, 2018 by uax6

[The Stationmaster]

An update on various items -

 

1.  Despite 1,000 tonnes of 'scrap' masts etc in store at Broughton aerodrome (I understand it's all unused material) going on sale there are numerous dumped foundation tubes and section of foundation tube littered around the GWML and adjacent work compounds - maybe they're the wrong kind of scrap?

 

2. Confirming Northroader's comments above plus some additional information -

a.  Masts are now complete and many booms are in place through the 'Steventon gap' with register arms etc present on most structures east of the bridge at Steventon.

b. Full catenary is present on both lines starting from one section of wiring west of Steventon - the missing section will finish between the level crossings and not all fittings appear to be in place yet for that

 

c. Fully wired catenary then extends all the way to Swindon ending as far as the Up Main is concerned in the vicinity of the site of Swindon Goods Yard Signalbox and as far as the Down Main is concerned just east of Highworth Branch Jcn.   However there is a gap of one section immediately east of Shrivenham on the Up Main; the Uffington gap is now wired.   It wasn't clear if the crossovers at Bourton are wired, I suspect they might not be.  Highworth Loop is wired as well.

 

d. Masts appear complete from the east end of Swindon right through to Wootton Bassett East with many booms in place through the Swindon station area including a new design for the longer multitrack booms which I have not seen before. All the other booms are of the 'lighter' style as seen at Twyford and elsewhere, a pleasant change from the 'over-boomed' horrors of Didcot.

 

e. There is one section of catenary in place on the Up Main east of Hay Lane and another just east of Wootton Bassett, catenary is more extensive on the Down Main coming almost as far east as the site of Rushey Platt junction and extending west of the site of Hay Lane signalbox (the worksite in that area is one the Down side).

 

f.  I don't think much more in the way of catenary has appeared on the Badminton route but masts look fairly complete as far west as Westerleigh Jcn and most have fittings.  Many masts are in position between Westerleigh and Parkway and those on the extended Down platform at Parkway also have booms in place.

[APOLLO]

An update on various items -

 

1.  Despite 1,000 tonnes of 'scrap' masts etc in store at Broughton aerodrome (I understand it's all unused material) going on sale there are numerous dumped foundation tubes and section of foundation tube littered around the GWML and adjacent work compounds - maybe they're the wrong kind of scrap?

 

 Scrap masts - Good Lord what is going on ?. -Send them up here for the Bolton to Wigan line !!

 

Brit15

[Titan]

An update on various items -

 

1.  Despite 1,000 tonnes of 'scrap' masts etc in store at Broughton aerodrome (I understand it's all unused material) going on sale there are numerous dumped foundation tubes and section of foundation tube littered around the GWML and adjacent work compounds - maybe they're the wrong kind of scrap?

 

 

 

 

 Scrap masts - Good Lord what is going on ?. -Send them up here for the Bolton to Wigan line !!

 

Brit15

 

Network rails procurement seems to be rather poor, there is another place I know stocked with a large quantity of 'spare' OLE equipment that is looking for a home...

[Peter Kazmierczak]

Scrap masts - Good Lord what is going on ?. -Send them up here for the Bolton to Wigan line !!

 

Brit15

Indeed.

 

Unless each item is made to measure, surely they could be used elsewhere.

Why can't the Didcot - Oxford section be wired now?

 

This reminds me of the joke about the Great Northern petering-out in a field beyond Doncaster.

Though this electrification project is way past being a joke anymore.

[HillsideDepot]

I wonder if they have sold for scrap the various missing masts from the Chippenham area?

 

There are odd ones missing along the embankment west of Chippenham, none in the station area (although there are reports of numerous people visiting to look at the station footbridge and scratch their heads) and another "gap" between Friday Street (east of Christian Malford halt) and somewhere west of Dauntsey station site.

 

In the presentation NR gave to Wiltshire Council at the outset of the project they said that the station footbridge provided sufficient clearance, but it seems they've had a remeasure (either that or the new clearance regs have come into play) and found a problem. But, the area has seen no work on masts, not even piling. 

 

Still, its not just NR who can't plan. The new booking office at Chippenham is now open, along with gate line which caused the office redesign. However the new booking hall, which does look very smart, has no leaflet racks. Because no one thought of that....

[Mike Storey]

Perhaps a silver lining is that this is not being managed by Greek Railways. 11 of their number now in custody for flogging "scrap" on backhanders to, what is described by the Greek judiciary as, "Romanies".

[jamie92208]

Perhaps a silver lining is that this is not being managed by Greek Railways. 11 of their number now in custody for flogging "scrap" on backhanders to, what is described by the Greek judiciary as, "Romanies".

 

That'll no doubt be the lot that did a stock take of locomotives a couple of years ago and found several missing believed scrapped.

 

Jamie

[jim.snowdon]

An update on various items -

 

Despite 1,000 tonnes of 'scrap' masts etc in store at Broughton aerodrome (I understand it's all unused material) going on sale there are numerous dumped foundation tubes and section of foundation tube littered around the GWML and adjacent work compounds - maybe they're the wrong kind of scrap?

 

These days, it seems that no Network Rail job is complete without a trail of leftover components littering the sides of the railway, probably because arranging the posessions to go out and collect them is difficult, costs money and does nothing for the project delivery. As for having a thousand tons of "scrap" material, that is either a severe case of bad planning on the part of the contractor, or if it material that could be used elsewhere, then at least it should be taken into stock and kept. Very little about OLE needs to be custom designed for a particular location.

 

Jim

[Trog]

You can also have the situation where unloading materials counts as project progress which looks good on the spread sheet, and is done despite there being no real chance of installing them.

 

WCRM unloaded miles of new rail for this reason which then laid in the cess for several years. The relaying work it was for having been cancelled as the WCRM program fell behind. The rail was then scrapped due to the risk that corrosion pits under the foot where it had been resting on the ground might cause rail breaks.

[Pandora]

It must be around 7 or 8 years back  NR made scrap clearance a priority and allocated budget for  OTMs and plant to run up and down line possessions "de-littering" of the PW, some examples of the scrap had become well- known landmarks for  train drivers braking points!

 

The railway was certainly a lot tidier in my neck of the woods at the end.

[phil-b259]

It must be around 7 or 8 years back  NR made scrap clearance a priority and allocated budget for  OTMs and plant to run up and down line possessions "de-littering" of the PW, some examples of the scrap had become well- known landmarks for  train drivers braking points!

 

The railway was certainly a lot tidier in my neck of the woods at the end.

 

Problem is, like vegetation clearance, scrap clearance needs to be a year round activity to be effective.

 

In a recent team brief, the head bods of the route put out a document with a few photos saying how wonderful it was that they had cleared away some scrap rail which had been sitting round for ages.

 

Only problem is that even before we got to be briefed about it, it seems as though the p-way had identified the newly cleared area as an ideal place to dump some scrap rail from another 'emergency' job......

 

I also know of a place where there has been redundant CWR sitting in the 4ft for what must be around 5 years now. Every so often we get the p-way to chop a bot off the end where it is starting to damage our (S&t) kit as it shuffles along with train vibration....

[corneliuslundie]

There have been five lengths of CWR flat bottomed rail in the four foot in Newtown station for well over a year. Not sure how one uses five lengths, especially as the platforms themselves are still bullhead!

Jonathan

[The Stationmaster]

Indeed.

 

Unless each item is made to measure, surely they could be used elsewhere.

Why can't the Didcot - Oxford section be wired now?

 

This reminds me of the joke about the Great Northern petering-out in a field beyond Doncaster.

Though this electrification project is way past being a joke anymore.

 

The big difference between what is (or isbn't) happening on the GWML now/recently and what happened on the ECML is that Don Heath isn't the Project Manager.  So we have 'progressed' from a situation where - as he should - the Project Manager was actually keeping an eye on the project and closely managing it to one where that clearly has not been happening.  From a situation where budgetted money was being wisely spent/ saved (which allowed electrification work to continue northwards beyond the original GN suburban scheme boundary) to one where costs have run way beyond budget and very plainly some of that is a consequence of abysmal use of resources and waste of money  (spending an 8 hour shift of a loco and train to unload a single foundation tube strikes me as gross waste and a nigh unequalled level of mismanagement).

 

Similarly putting out to tender 1,000 tonnes of steelwork which could be used on uncompleted electrification work also seems to me to be a scandalous waste unless it can somehow be replaced at less that the current scrap steel price of £100 per tonne.  I wonder how many masts and booms they are holding in stock to replace any material damaged by derailments or even events from outside the railway fence?