GWML Electification

[jim.snowdon]

Continental catenary tends to be more resistant to uplift force than BR version although I thought - from various past things said about it by NR - that the new GWML catenary is more highly tensioned than traditionla UK catenary hence the problem with Class 387 pantograph carbons.

 

But one BR catenary which is not good when it comes to resisting pantograph uplift force is the headspan stuff, French engineers were amazed how bad it was in resisting pantograph uplift.

Pretty well every other railway's OLE appears to be stiffer than that which has been installed on the GW, which seems particularly soft. Watching 8xx units go through West Drayton at line speed, the wire uplift is considerable and leaves quite large amplitude oscillations in the wire for the better part of five minutes. What is evident is that the GW catenary wire is flatter than many, which means that it is more highly tensioned. It also means that it is more susceptible to uplift as more of the wire mass is being carried by the tension. With greater sag, the uplift from the pantograph is balanced by more of the mass of the OLE.

 

Jim

[St. Simon]

Pretty well every other railway's OLE appears to be stiffer than that which has been installed on the GW, which seems particularly soft. Watching 8xx units go through West Drayton at line speed, the wire uplift is considerable and leaves quite large amplitude oscillations in the wire for the better part of five minutes. What is evident is that the GW catenary wire is flatter than many, which means that it is more highly tensioned. It also means that it is more susceptible to uplift as more of the wire mass is being carried by the tension. With greater sag, the uplift from the pantograph is balanced by more of the mass of the OLE.

Jim

Interesting, at Tilehurst it seems to me (admittedly I don't know enough about the physics behind OLE design) that there is hardly any uplift in the wire as Class 80x (or Class 387s) pass, uncertainly not as much as a Class 390 at Milton Keynes last weekend.

 

I wander if the stuff at West Drayton has just been used more than the stuff at Tilehurst making it softer?

 

Simon

[Mike Storey]

Pretty well every other railway's OLE appears to be stiffer than that which has been installed on the GW, which seems particularly soft. Watching 8xx units go through West Drayton at line speed, the wire uplift is considerable and leaves quite large amplitude oscillations in the wire for the better part of five minutes. What is evident is that the GW catenary wire is flatter than many, which means that it is more highly tensioned. It also means that it is more susceptible to uplift as more of the wire mass is being carried by the tension. With greater sag, the uplift from the pantograph is balanced by more of the mass of the OLE.

 

Jim

 

I bow to your far superior knowledge Jim, but my incidental observations of the new LGV from Tours to Bordeaux (Ocean, primarily headspan equipped), suggest that such disturbance to the OLE is not confined to the GW. My gast was actually flabbered when I sat watching the passing of trains some miles north of Angouleme, in the aftermath.

[Coryton]

Interesting, at Tilehurst it seems to me (admittedly I don't know enough about the physics behind OLE design) that there is hardly any uplift in the wire as Class 80x (or Class 387s) pass, uncertainly not as much as a Class 390 at Milton Keynes last weekend.

 

I wander if the stuff at West Drayton has just been used more than the stuff at Tilehurst making it softer?

 

Simon

 

Bending metals normally makes them harder. (Putting a bend in a piece of stiff wire is easy enough if it isn't too thick...straightening it out again is another matter...)

[woodenhead]

I suppose with all this pan down running under wires that the one side benefit of Bi-modes is shining through - when you have OHLE problems your trains can keep running subject to there not being a line or lines blocked.

[Gilbert]

I wonder if today's very high winds will have any effect on the catenary..

[Fat Controller]

I wonder if today's very high winds will have any effect on the catenary..

As they seem to have done on the ECML?

[The Stationmaster]

Interesting, at Tilehurst it seems to me (admittedly I don't know enough about the physics behind OLE design) that there is hardly any uplift in the wire as Class 80x (or Class 387s) pass, uncertainly not as much as a Class 390 at Milton Keynes last weekend.

 

I wander if the stuff at West Drayton has just been used more than the stuff at Tilehurst making it softer?

 

Simon

 

The same at Twyford - with 80X trains going through at full belt on the Mains (when they are running on electricity that is) there is very little movement in the contact wire.  A very stark contrast with ECML headspan wiring where a movement c.6" either side of normal height was measured when testing at 125mph and the oscillation took a long time to die down; far too long for 18 car E Class 373s to run at 125mph with the original BR pantographs.

[Afroal05]

I suppose with all this pan down running under wires that the one side benefit of Bi-modes is shining through - when you have OHLE problems your trains can keep running subject to there not being a line or lines blocked.

 

Absolutely, although when the wires came down outside of Paddington back in October and there was a total switch off, whilst you could have run diesels on the relief lines they were all blocked with stranded 387s! 

[Covkid]

I suppose with all this pan down running under wires that the one side benefit of Bi-modes is shining through - when you have OHLE problems your trains can keep running subject to there not being a line or lines blocked.

 

All very well for GWR with a full fleet of Bimode IETs. Not so good for the LNER 801s though when they are eventually gotten into traffic. Wires down at Carlton crossing Newark on Thursday night resulted in some northbound trains arriving 5 hours late. Still waiting to read how quickly an 801 can move using the solitary MTU for power  

[Titan]

All very well for GWR with a full fleet of Bimode IETs. Not so good for the LNER 801s though when they are eventually gotten into traffic. Wires down at Carlton crossing Newark on Thursday night resulted in some northbound trains arriving 5 hours late. Still waiting to read how quickly an 801 can move using the solitary MTU for power  

 

The LNER 801's still have one diesel engine that can provide traction power for emergency recovery, or provide ETS should it be trapped by other trains. It is just intended to be able to get the train to some live wire, not move it anywhere at any kind of speed.

Edited December 1, 2018 by Titan

[jamie92208]

The LNER 801's still have one diesel engine that can provide traction power for emergency recovery, or provide ETS should it be trapped by other trains. It is just intended to be able to get the train to some live wire, not move it anywhere at any kind of speed.

 

I have a vague memory that 20mph on level track has been quoted but can't be sure.   Just hope they don't operate over the Lickey.

 

Jamie

[Mike Storey]

I have a vague memory that 20mph on level track has been quoted but can't be sure.   Just hope they don't operate over the Lickey.

 

Jamie

 

Designed just to get them to the next station during a power failure Jamie. If that speed is true, it is 20mph faster than a Class 317 or 465 in such circumstances, for example!

[SouthernMafia]

Reading West this morning. Pan came down shortly after. IET came off Reading W Curve.

[Coryton]

Designed just to get them to the next station during a power failure Jamie. If that speed is true, it is 20mph faster than a Class 317 or 465 in such circumstances, for example!

 

Or presumably, if appropriate, to the next bit where there is power.

 

I know it doesn't help if the wires have been brought down, but I'm sure there will be times where there are intact wires but no electricity in them.

 

I believe that at present electric trains are sometimes permitted to coast through such an area - having an o-board engine to assist seems like an excellent plan to me - should make it much less likely that a train becomes stranded without power because the brakes didn't stay off or for any other reason.

[jamie92208]

Or presumably, if appropriate, to the next bit where there is power.

 

I know it doesn't help if the wires have been brought down, but I'm sure there will be times where there are intact wires but no electricity in them.

 

I believe that at present electric trains are sometimes permitted to coast through such an area - having an o-board engine to assist seems like an excellent plan to me - should make it much less likely that a train becomes stranded without power because the brakes didn't stay off or for any other reason.

 

Being a tad cynical it could provide enough power to keep phones/laptops charged on board and stop the passengers becoming revolting.   A friend of mine was on an ECML service when a foil party balloon caused a short circuit and brought the wires down in front of his train. He was not very complementary about his fellow passengers as they started to panic as their phone batteries ran down.   They were somewhere rural and none of them had the sense to turn their phones off and stop surfing the net.

 

Jamie

[Coryton]

Being a tad cynical it could provide enough power to keep phones/laptops charged on board and stop the passengers becoming revolting.   A friend of mine was on an ECML service when a foil party balloon caused a short circuit and brought the wires down in front of his train. He was not very complementary about his fellow passengers as they started to panic as their phone batteries ran down.   They were somewhere rural and none of them had the sense to turn their phones off and stop surfing the net.

 

Jamie

 

Nothing wrong with keeping passengers happy when things have gone very wrong.

 

Whether that alone justifies lugging around a diesel engine and a tank full of fuel for the occasional time it's needed is another matter.

[woodenhead]

Or presumably, if appropriate, to the next bit where there is power.

 

I know it doesn't help if the wires have been brought down, but I'm sure there will be times where there are intact wires but no electricity in them.

 

I believe that at present electric trains are sometimes permitted to coast through such an area - having an o-board engine to assist seems like an excellent plan to me - should make it much less likely that a train becomes stranded without power because the brakes didn't stay off or for any other reason.

Coasting is something acceptable on the ECML and I guess and IEP can coast quite some way before putting on the diesel to get it home - in fact I imagine powered coasting with the get me home engine might further the coasting distance until finally it succumbs to 20 mph.

 

Being a tad cynical it could provide enough power to keep phones/laptops charged on board and stop the passengers becoming revolting.   A friend of mine was on an ECML service when a foil party balloon caused a short circuit and brought the wires down in front of his train. He was not very complementary about his fellow passengers as they started to panic as their phone batteries ran down.   They were somewhere rural and none of them had the sense to turn their phones off and stop surfing the net.

 

Jamie

The main thing people do is complain on Facebook, Twitter and to the BBC about how delayed their train is, a bit of video too in the hope of going viral and maybe a Skype to the BBC news desk so you can describe the horrendous conditions in your metal box safe from the elements whilst an orange brigade try and fix the situation regardless of the weather.

[Coryton]

The main thing people do is complain on Facebook, Twitter and to the BBC about how delayed their train is, a bit of video too in the hope of going viral and maybe a Skype to the BBC news desk so you can describe the horrendous conditions in your metal box safe from the elements whilst an orange brigade try and fix the situation regardless of the weather.

 

I'd agree with your implication that people often exaggerate how bad things are.

 

But I think people stuck on a train for hours this summer with no air conditioning or opening windows really did have something to complain about. They would have been better off out in the elements rather than in their metal box.

[Chris116]

The failures of current electrification projects just show how sensible BR were to do the London to Manchester scheme by starting with Crewe to Manchester. If they had started in London the project would have been cancelled by the time they got to Coventry or maybe Birmingham!

 

If the GWML project had started at Penzance and Swansea there is no chance that the London end would have been cancelled by our wonderful masters! Trouble is BR were reasonably independent while the DafT lot have far too many thumbs in pies they do not understand.

Edited December 10, 2018 by Chris116

[Trog]

Coasting is something acceptable on the ECML and I guess and IEP can coast quite some way before putting on the diesel to get it home - in fact I imagine powered coasting with the get me home engine might further the coasting distance until finally it succumbs to 20 mph.

 

 

A driver I knew had his loco fail at Bourne End Neutral Section, and he coasted from there eventually having to stop at a red signal half way down Camden Bank ( about 25 miles further on). He then used the SPT to report to Euston Box that his loco had failed at Bourne End.

[The Stationmaster]

Puzzling sight of the day.  I noticed today that at Swindon the 'Cheltenham bay' has full catenary in place and I must admit to wondering why because it is too short to hold any electric unit currently operating on the GWML or (on present information) ever likely to do so.  In fact I wonder if there are any 2 car 25kv powered EMUs anywhere on the network now?

[bimble]

Puzzling sight of the day.  I noticed today that at Swindon the 'Cheltenham bay' has full catenary in place and I must admit to wondering why because it is too short to hold any electric unit currently operating on the GWML or (on present information) ever likely to do so.  In fact I wonder if there are any 2 car 25kv powered EMUs anywhere on the network now?

 

Wikipedia lists a handful of 3 car units (such as the 331 or 334), though no two car units...

[david.hill64]

Puzzling sight of the day.  I noticed today that at Swindon the 'Cheltenham bay' has full catenary in place and I must admit to wondering why because it is too short to hold any electric unit currently operating on the GWML or (on present information) ever likely to do so.  In fact I wonder if there are any 2 car 25kv powered EMUs anywhere on the network now?

Two car 25kV EMUs have I think always been a rare beast. I can think only of the Clacton sets, but then my memory isn't what it was.

 

Perhaps the bay has been electrified as a charging point for Vivarail................................

[St. Simon]

Puzzling sight of the day.  I noticed today that at Swindon the 'Cheltenham bay' has full catenary in place and I must admit to wondering why because it is too short to hold any electric unit currently operating on the GWML or (on present information) ever likely to do so.  In fact I wonder if there are any 2 car 25kv powered EMUs anywhere on the network now?

 

Chances are that it was just for ease and for passive provision just in case 2 or 3 car electric units are used later on. The Sectional Appendix shows the platform is 80m long, is in theory it is long enough for a 4-car Electrostar, but I doubt you can actually fit on in unless you kiss the buffers!

 

Simon