GWML Electification

[ess1uk]

so what went wrong this week?

[Wickham Green too]

Whatever it was seems to have brought down the knitting on ALL the lines .......... and has now spread to the East Coast Main Line !

[ess1uk]

6 minutes ago, Wickham Green too said:

Whatever it was seems to have brought down the knitting on ALL the lines .......... and has now spread to the East Coast Main Line !

that was someone throwing things at Stevenage?

[RJS1977]

22 hours ago, ess1uk said:

so what went wrong this week?

 

I understand that the problem was at Hayes & Harlington, so would have been part of the Heathrow electrification project rather than the GWML electrification per se, which started a little beyond Airport Junction.

 

(edit - in fact, strictly speaking the GWML electrification project began at Maidenhead as Airport Junction-Maidenhead was part of the Crossrail project).

Edited September 21, 2022 by RJS1977

[jamie92208]

5 hours ago, RJS1977 said:

 

I understand that the problem was at Hayes & Harlington, so would have been part of the Heathrow electrification project rather than the GWML electrification per se, which started a little beyond Airport Junction.

On the Royal Train thread someone mentioned that it was near Hayes on the stretch that uses headspans so when one wire was brought down the whole lot came down.

 

Jamie

[Mike_Walker]

The incident took place around 06:35 between Hayes & Harlington and Southall West Junction and train involved was 1K01, the 05:34 Bedwyn to Paddington worked by 800024. 

 

This section of the GWML is still equipped with the headspans installed for the Heathrow electrification in the early 1990s and in such areas damage to the OLE above one line almost always results in damage to the wiring above all lines and this is what happened on Monday.  At the time of the incident the train is reported to have been travelling at 52mph as it was slowing to observe a 50mph temporary speed restriction commencing at Southall West Junction but it still managed to destroy around 2 miles of overhead line as well as the unit's pantograph.

 

The result was that not only was 1K01 halted but all trains in the area were brought to a stand and several had to be evacuated where they stood.  Network Rail repair crews did not reach the site until midday.  All services were cancelled between Reading and Paddington although a limited shuttle was established between Reading and Slough.  By late evening this was extended into Paddington.  On Tuesday a limited service operated between Paddington and Reading but this was suspended at 20:00 to allow crews unlimited access to complete the repair work.

 

An investigation is underway to determine the cause which basically is either a pantograph problem on the train or a defect on the OLE.  I understand that early indications are pointing to the latter.

[Wickham Green too]

10 minutes ago, Mike_Walker said:

.. either a pantograph problem on the train or a defect on the OLE. ...

Presumably could have been a relatively minor fault on both  -  each of which wouldn't have been disastrous by itself.

[Oldddudders]

Inevitably the GWR fleet has been displaced by the service disruption, so my semi-fast 14.36 Padd - Paignton is 5 vice 9, and overloaded over certain sections, causing delays at stations. It is bums out windows from St Davids, with the usual studente population heading back to NA and Torbay. 

[icn]

On 31/12/2021 at 19:16, The Stationmaster said:

Sorry to be  very late to ths party but something seems very amiss here and I wonder if it is the trains or the OLE?  In most designs of overhead electric train I have ever come across - including Class 373 Eurostars - run off OLE with the pan raised the pan will go overheight and auto lower.  No external controls of any sort are used - the pan will do that all on its own and controlled by whatever is built into the traction unit if it is not lowered by the Driver.    OLE design is (or rather in BR days was) planned to take account of this and a pan going overheight would not damage the OLE because the rise of the contact wire would be sufficient to make a pan safely go overheight without damaging the OLE.  A balise could no doubt do the same in a simpe, situation but that is not an excuse, nor should it be used as one, for the OLE to be planned and constructed without proper run off arrangements.

 

I can only speculate as I haven't seen any explanation of what could go wrong - but I think I can imagine what it might be. I could of course be completely wrong - but I suspect that in that case I may at least rile up someone with better knowledge to provide a better explanation.

 

Suppose you have an electrified double track main line, and a diverging unelectrified branch line - with a double junction as follows:

And now suppose you have an electric train running left to right on the bottom mainline (wrong direction for British practice I know), but it has erroneously been routed onto the branch line. And let's assume that there are only two wires - one above each main line. The pantograph will start rising just after the point (A'B'), and collide with the wiring above the Diamond. Depending on how fast the auto-lower mechanism kicks in and depending on the speed of the train this might not happen - but judging by the speeds I see in practice it seems very likely.

 

Is this similar to the situation in Cardiff? I don't know, I'd have to go there to find out.

[The Stationmaster]

20 hours ago, icn said:

 

I can only speculate as I haven't seen any explanation of what could go wrong - but I think I can imagine what it might be. I could of course be completely wrong - but I suspect that in that case I may at least rile up someone with better knowledge to provide a better explanation.

 

Suppose you have an electrified double track main line, and a diverging unelectrified branch line - with a double junction as follows:

And now suppose you have an electric train running left to right on the bottom mainline (wrong direction for British practice I know), but it has erroneously been routed onto the branch line. And let's assume that there are only two wires - one above each main line. The pantograph will start rising just after the point (A'B'), and collide with the wiring above the Diamond. Depending on how fast the auto-lower mechanism kicks in and depending on the speed of the train this might not happen - but judging by the speeds I see in practice it seems very likely.

 

Is this similar to the situation in Cardiff? I don't know, I'd have to go there to find out.

You are completely wrong.  In the Hayes are all running lines are electrified and in any case there are no facing points between Airport Jcn and Southall East and from what Mike Walker says above the train didn't even get to Southall East.

 

In any case what you surmise would only happen at a major junction where there is no run off on the divergent line(s) and there aren't many of those for normal direction running which are approached at speed on the GWML.

 

The wider impact of this de-wirement , or whatever it was, might well have been lessened if the original proposal in the GWML electrification scheme to eliminate headspan wiring west of Acton station had been fully implemented but, no doubt to save money, it hasn't been.  

[Mike_Walker]

Actually it was Southall West which is facing from UR to UM and DM to DR.  I think all the junctions on to non-electrified lines off the GWML have run-off wiring for just such eventualities.

[icn]

On 02/10/2022 at 12:41, The Stationmaster said:

You are completely wrong.  In the Hayes are all running lines are electrified and in any case there are no facing points between Airport Jcn and Southall East and from what Mike Walker says above the train didn't even get to Southall East.

 

In any case what you surmise would only happen at a major junction where there is no run off on the divergent line(s) and there aren't many of those for normal direction running which are approached at speed on the GWML.

 

The wider impact of this de-wirement , or whatever it was, might well have been lessened if the original proposal in the GWML electrification scheme to eliminate headspan wiring west of Acton station had been fully implemented but, no doubt to save money, it hasn't been.  

I was responding to a post asking about the oddities in Cardiff, where the 800s have to switch to Diesel while remaining under the wires - admittedly neither the quoted section nor my post made that explicit.

[St. Simon]

5 hours ago, icn said:

I was responding to a post asking about the oddities in Cardiff, where the 800s have to switch to Diesel while remaining under the wires - admittedly neither the quoted section nor my post made that explicit.

Hi,

 

See page 233 for the full argument about Cardiff :)

 

[icn]

On 08/10/2022 at 19:08, St. Simon said:

Hi,

 

See page 233 for the full argument about Cardiff :)

 

I've read that page, but that's precisely what I'm referring to:

 

Specifically these sentences: "it is because  the risk of a significant de-wirement event, should the driver get it wrong and a pantograph still be raised when the wires ran out, was too great, and frankly, it turns out it is needed at Cardiff." and "The issue is that if it started off to Swansea or the Valley (? Sorry, can't remember from the scheme plan) with it's pan up then it would do very significant damage to the OLE."

 

No one has explained why this damage would occur. No one seems to dispute that the pantograph will come down eventually, so presumably there has to be something that the pantograph could hit after leaving the wires and before it automatically drops?

[St. Simon]

37 minutes ago, icn said:

I've read that page, but that's precisely what I'm referring to:

 

Specifically these sentences: "it is because  the risk of a significant de-wirement event, should the driver get it wrong and a pantograph still be raised when the wires ran out, was too great, and frankly, it turns out it is needed at Cardiff." and "The issue is that if it started off to Swansea or the Valley (? Sorry, can't remember from the scheme plan) with it's pan up then it would do very significant damage to the OLE."

 

No one has explained why this damage would occur. No one seems to dispute that the pantograph will come down eventually, so presumably there has to be something that the pantograph could hit after leaving the wires and before it automatically drops?

Hi,

 

Ah, I see, the problem is that there are OLE wires for a wired route crossing the unwired route a train could be travelling along.

 

By the time the trains reached this, having run off the wires for it’s own route, the pantograph head would be between the contact wire and caternary wire and therefore tear through the wire and in turn bring down the OLE wires across the entire junction.

 

Simon 

Edited October 15, 2022 by St. Simon

[Banger Blue]

On 30/10/2021 at 13:54, St. Simon said:

The reason for providing the Automated Back Up via ETCS Packet 44 Data was NOT because of a 'lack of trust' of signallers or drivers, it is because  the risk of a significant de-wirement event, should the driver get it wrong and a pantograph still be raised when the wires ran out, was too great, and frankly, it turns out it is needed at Cardiff. There are other ends of OLE on the Great Western that don't have Balises installed as has been assessed to be low risk if the driver gets it wrong.

Would I be right then, in thinking, that these Balises weren’t installed in the Newbury area?

[Mike_Walker]

They are but something went wrong with 1C78 today - either the balise or on the train.  It's happened there before apparently.

[St. Simon]

4 hours ago, Banger Blue said:

Would I be right then, in thinking, that these Balises weren’t installed in the Newbury area?

Hi,

 

There are Balises for end of OLE protection for the limit of OLE at Newbury on the approach to Newbury, but the (manual) Power Change-Over area is on the approach to Newbury Racecourse station with the 'Stop Immediately if Pantograph not lowered' sign on immediate approach to the junction at Newbury Racecourse.

 

I’m guessing something has happened there?

 

Simon

Edited August 14, 2023 by St. Simon

[Grovenor]

On 15/10/2022 at 13:43, St. Simon said:

Hi,

 

Ah, I see, the problem is that there are OLE wires for a wired route crossing the unwired route a train could be travelling along.

 

By the time the trains reached this, having run off the wires for it’s own route, the pantograph head would be between the contact wire and caternary wire and therefore tear through the wire and in turn bring down the OLE wires across the entire junction.

 

Simon 

So a rather silly attempt to save a bit on the OLE design. Penny wise pound foolish!

[Banger Blue]

2 hours ago, St. Simon said:

Hi,

 

There are Balises for end of OLE protection for the limit of OLE at Newbury on the approach to Newbury, but the (manual) Power Change-Over area is on the approach to Newbury Racecourse station with the 'Stop Immediately if Pantograph not lowered' sign on immediate approach to the junction at Newbury Racecourse.

 

I’m guessing something has happened there?

 

Simon

Oops, something hasn’t worked then!
The pantograph on 800316 lost an argument with a bridge on the Westbury side of Newbury today.

[St. Simon]

3 minutes ago, Banger Blue said:

Oops, something hasn’t worked then!
The pantograph on 800316 lost an argument with a bridge on the Westbury side of Newbury today.

Hi,

 

Hmmmmmmm, I’ll ask around tomorrow!

 

Simon

[jamie92208]

1 hour ago, Banger Blue said:

Oops, something hasn’t worked then!
The pantograph on 800316 lost an argument with a bridge on the Westbury side of Newbury today.

Maybe that bridge wilbe one as famous as the tunnel just West of Dollands Moor. I believe several Eurostar pantograph were caught there before HS1 opened. 

 

Jamie

[Mike_Walker]

13 hours ago, Grovenor said:

So a rather silly attempt to save a bit on the OLE design. Penny wise pound foolish!

Not really, the automatic end operation of the pantograph and engine management at the boundary of the OLE takes a task out of the driver's responsibility allowing him to concentrate on the safe operation of the train.  In this case not all trains stop at Newbury to effect a manual changeover.   The driver can see this has happened correctly from the TMS display in the cab and should therefore intervene if it does not.  As mentioned, the pan on 800316 failed to lower yesterday and hit the first bridge beyond the end of the OLE which at Newbury extends far enough west of the station to enable a turnback move to be made over the crossover.  To early to say what/why but no doubt several "please explains" have been circulating.

 

It is quite permissible to switch manually between diesel and electric only operation at full line speed in specifically designated areas and elsewhere at low speed (IIRC up to 20mph).

[40052]

Are these trains not fitted with ADD, or is the distance between the end of the OLE and the bridge insufficient to allow the ADD to be effective in time? 

[Mike_Walker]

Yes they are and the distance between the end of the OLE and the next bridge is 33 chains.  1C78 was non-stop so potentially was travelling at up to 110mph so whether this allows sufficient time for the ADD to activate I can't say.  

 

13 hours ago, Grovenor said:

So a rather silly attempt to save a bit on the OLE design. Penny wise pound foolish!

Given that automated power changes take place probably hundreds of times daily across the GW network (and elsewhere) without incident and those such as this can be counted on the fingers of one hand since they were introduced would suggest that is far from the case.