ETCS, the 2012 Olympics, IEP & Intercity 225

[noiseboy72]

A rough count of trains through Grantham today indicated that only about half are electrified ( 95% 225s and a very few frieght) with the rest a mix of 125s, local sprinters, whatever those DMUs Hull Trains use and 66s pulling the frieght.

I would imagine that any more elctric trains would require a wholesale upgrade of the OHLE, as I understand that when the White Rose Eurostar 373s were running, they had to be used off peak as their power consumption was so much higher than a 225 that an extra electrical "path" was required for them.

 

Swapping locos is obviously a nonesense. As discussed, it leads to greater potential for failure, delays and accidents.

 

From my perspective as a ECML user, we need more seats and more line capacity so that the intercity trains can run unhindered at high speed, missing out the commuter stations south of Grantham and moving frieght to a dedicated line. When the GER was built, this was what was supplied. A "Towns" line for passenger with a slow and fast set for local and long distance and a "Country" line for frieght. The Beeching cuts eradicated the country line and so we are stuck with slow frieght on the main line. Quadrupling the main line in parts has helped, but many 2 line sections remain....But I digress !

 

The White Rose 373s were a fantastic train. I would schedule meetings so that I could use them. Fast, quiet and with so many more seats available, you could feel the acceleration. Something similar to replace the creaking, groaning, rocking draughty 225s and the more comfortable but slightly seedy 125s would be great.

 

Signaling aside, I can't see how you could run many services at 140MPH with the current level of slow trains on the line. I agree with the poster that faster accelerating trains would help, as would more fast lines direct through stations so that stopping trains can be overtaken by the intercitys.

[vc-10]

Are there not 4 tracks on the southern end of the ECML? 2 for stoppers and 2 for high speed trains. The GWML has 4 tracks from Didcot to Paddington. I remember Tornado getting stuck behind a commuter train on Top Gear.

 

Regarding joining/splitting trains, SWT split 159/158s all the time at Salisbury. Takes a few minutes, but it's not really a problem. The train leaves Waterloo in 2/3 portions, 1 or 2 carry on to Yeovil/Exeter (and I think Gillingham sometimes), 1 sometimes goes on to Bristol, and any remaining go into the traincare depot. On the journey up to London, the Bristol train arrives first into Salisbury (or a 'new' set from the depot) and sits in the platform, and then the western set arrives and joins up before the train continues to London. I don't see why a high speed unit (Voyager/180 style) couldn't run like this if properly designed!

[Ron Ron Ron]

......i do think that the development of the bi-mode concept is a grave waste of investment that could be better spent elsewhere......

There's no "waste of investment" as the Bi-Mode trains are just combinations of standard vehicles used in other SET formations. There's nothing unusual or special about them.

If electrification is later extended along a route where Bi-mode is employed, so that the "self powered" element is no longer needed, then the Bi-Mode train is simply re-configured to all-electric (swapping out one vehicle for another) and the surplus diesel/hybrid generator driving vehicle will be redeployed either to another Bi-Mode fleet or to an all-diesel/hybrid fleet.

 

The original IEP spec. "preferred" that surplus generator driving vehicles could be ultimately converted to electric driving vehicles if electrification eventually left them redundant, but it wasn't an exact requirement.

As I read it, Hitachi SET diesel/hybrid driving vehicles are of a different construction to all other SET vehicles (e.g. heavier constuction etc,) so may not be convertable or easily convertable to accomodate passengers, but I'm sure they could be converted to run as DVT style vehicles with the electric power kit fitted.

 

 

....Surely off the peg equipment would make more sense, buying tried and tested equipment (obviously shrunk to fit the british loading gauge).......

Frobisher has largely answered this....

 

Erm, Hitachi's SET proposal is pretty much completely "off the peg" - it certainly bears more than a passing resemblence to the Class 395 in the way the traction motors and power setup are done. The distributed traction motors set up is pretty much what all new train sets have had for the last ten years and the benefits of which are well known (Pendalino, Voyager, 395, plus certain multiple units).

Buying "off-the peg", "shrunk to fit the british loading gauge" is more or less what is being proposed and I doubt it would come cheaper in any other form.

There are certainly some similarities to the Class 395's but this is an all-new train and quite different in many respects. Much of the technology comes from existing modern Hitachi units operating in or ordered for Japan, Korea, China, Taiwan, Singapore; and not forgetting the latest Hitachi N700 Series Shinkansen.

The diesel/hybrid technology is already beginning to be deployed elsewhere (e.g. Japan) and is being looked at by several train manufacturing companies around the world, even by GE for use in heavy US freight locos.

 

Pretty much any option for new IC trains designed to serve to the middle of the 21st century would include some of the latest technology available, balanced against realistic costs and technological risks. The proposed solution does seem to balance the "tried and tested" with the "new" quite well IMHO.

 

 

.

[Glorious NSE]

That's fast becomming an urban myth and I refer the honoprable gentleman to http://www.agilitytr...eleased-1_5.pdf That's 4MW as against a single HST power car's 2MW or a Class 91's 4.7MW. The distributed traction package (plus lighter overall weight) of the SET means that it will have superior acceleration to the slightly higher rated Class 91 plus MK4's.

 

Yet folk that do have a bit of experience/knowledge in this field are still saying it...see Informed Sources in MR Jan, still reckoning the diesel to need to run 30% of the time on electric.

 

Just saying is all...i'm not the engineer.

 

Regarding joining/splitting trains, SWT split 159/158s all the time at Salisbury. Takes a few minutes, but it's not really a problem. The train leaves Waterloo in 2/3 portions, 1 or 2 carry on to Yeovil/Exeter (and I think Gillingham sometimes), 1 sometimes goes on to Bristol, and any remaining go into the traincare depot. On the journey up to London, the Bristol train arrives first into Salisbury (or a 'new' set from the depot) and sits in the platform, and then the western set arrives and joins up before the train continues to London. I don't see why a high speed unit (Voyager/180 style) couldn't run like this if properly designed!

 

I'm with you entirely - SWT's operation there is textbook, well worth a visit if you're under the mistaken impression that it's impossible to join/split modern (well, those are 1980s/90s) trains in a sensible time with people on. Regularly.

 

And before you guys all say "but they are pre-onboard computer" - Southern do the same thing in places with 377s...

 

Design the train properly to do it and it will be able to do it. Boringly well, every day.

 

How so? If this idea was so good, why isn't it done with the 225's already so that the service could be run to Aberdeen?

 

GNXEACML...whatever they are called this week have to run lots of 125's at the moment as there are not enough 225s to run an all electric service anyhow, so diagramming a 225 to run off-wire would presumably mean a 125 was then running a service entirely under wire when it could be off up to Aberdeen...

 

I'll try and put that a bit more clearly, yes you could add/swap to a diesel to take a 225 set up north, but it makes absolutely no sense at the moment for them to do so as you don't have "spare" 225 sets doing nothing but you do have lots of 125 sets which you need to use somewhere - pretty obvious to use the diesel trains on the route that needs a diesel train and the electric train on the one that is electric!

 

It's a bit of a pointless argument.

[frobisher]

Yet folk that do have a bit of experience/knowledge in this field are still saying it...see Informed Sources in MR Jan, still reckoning the diesel to need to run 30% of the time on electric.

 

Just saying is all...i'm not the engineer.

 

There are plenty of vested interests out there, just saying... When looking to claims about a product that hasn't been built yet I'd prefer to believe what the manufacturer thinks its product is capable of rather than an expert who has made assumptions about the construction of said product.

 

GNXEACML...whatever they are called this week have to run lots of 125's at the moment as there are not enough 225s to run an all electric service anyhow, so diagramming a 225 to run off-wire would presumably mean a 125 was then running a service entirely under wire when it could be off up to Aberdeen...

 

I'll try and put that a bit more clearly, yes you could add/swap to a diesel to take a 225 set up north, but it makes absolutely no sense at the moment for them to do so as you don't have "spare" 225 sets doing nothing but you do have lots of 125 sets which you need to use somewhere - pretty obvious to use the diesel trains on the route that needs a diesel train and the electric train on the one that is electric!

 

It's a bit of a pointless argument.

 

The reason that it's short NOW is because that's what there is. This goes back to when BR ordered the 225 sets. The argument, such as it is, is not "why isn't it being done NOW?" but "why wasn't it ever done?".

[Edwin_m]

There are plenty of vested interests out there, just saying... When looking to claims about a product that hasn't been built yet I'd prefer to believe what the manufacturer thinks its product is capable of rather than an expert who has made assumptions about the construction of said product.

 

Surely the manufacturer is potentially the greatest vested interest of all?

[Rhydgaled]

The reason that it's short NOW is because that's what there is. This goes back to when BR ordered the 225 sets. The argument, such as it is, is not "why isn't it being done NOW?" but "why wasn't it ever done?".

They have probablly never had enough 225s to warrant swaping the locos to extend services beoynd the wires since the electrification was completed along the whole length. In other words they probablly only ordered enough to run the required all-under-the-wires services. Even if that wasn't the case, when running with Mrk3s the 91 couldn't provide power to the coaches so the HST power car had to do this instead. Therefore it may be the case that a HST power car and pretty much any other deisel locomotive wouldn't be able to provide power to Mrk4 coaches.

 

Also those SIG bogies were fixed weren't they? by the British? Perhaps.

[Edwin_m]

That's fast becomming an urban myth and I refer the honoprable gentleman to http://www.agilitytrains.com/assets/pdf/AT-090205-Key_Facts-Released-1_5.pdf That's 4MW as against a single HST power car's 2MW or a Class 91's 4.7MW. The distributed traction package (plus lighter overall weight) of the SET means that it will have superior acceleration to the slightly higher rated Class 91 plus MK4's.

 

This table states that the bi-mode has 4MW on electric power, same as the electric version, and 2MW on diesel. Further down in the same link, it confirms what someone has already posted, that the diesel power car replaces one of the two pantograph/transformer cars. This halves the installed power when running on straight electric.

 

Hence I believe the quoted 4MW is the figure with the diesel running, and much more importantly, the experts quoted in Modern Railways interpret it this way too. Confusing, yes. Intentionally misleading, maybe.

[Rhydgaled]

This table states that the bi-mode has 4MW on electric power, same as the electric version, and 2MW on diesel. Further down in the same link, it confirms what someone has already posted, that the diesel power car replaces one of the two pantograph/transformer cars. This halves the installed power when running on straight electric.

 

Hence I believe the quoted 4MW is the figure with the diesel running, and much more importantly, the experts quoted in Modern Railways interpret it this way too. Confusing, yes. Intentionally misleading, maybe.

So, that clears that up, the bi-mode IEP/SET really would only have half the power, unless running on electrified lines with the diesel fired up as well.

 

How much older are the Intercity 125s than the 225s? It says in this document (on page 4 - under the heading "Intercity Express Program") that the 125s are life extended for service up to around 2016. With timescales for installation of cab signaling of 2015 - 2018, this document mentioning that somebody somewhere said ERTMS/ETCS should have been implemented here by 2010 but that the reply to this was that it couldn't be completed until 2015, it should just about be feasible and possible to have the 225s running at 140mph on the conventional lines. Admittadly the feasibilty is only marginal. If only the works could be brought forward, I would have a much stronger case then.

 

The high speed 1 deployment would allow the 225s to start running at 140 at a much earlier date, giving more 140mph useage and therefore making the money spent on fitting them with ERTMS/ETCS go further, so to speak. This should be enough, the problem might be with insufficent requirements for high speed 1 services or insufficent rolling stock to replace any 225s that move to high speed 1.

[The Stationmaster]

 

How much older are the Intercity 125s than the 225s? It says in this document (on page 4 - under the heading "Intercity Express Program") that the 125s are life extended for service up to around 2016. With timescales for installation of cab signaling of 2015 - 2018, this document mentioning that somebody somewhere said ERTMS/ETCS should have been implemented here by 2010 but that the reply to this was that it couldn't be completed until 2015, it should just about be feasible and possible to have the 225s running at 140mph on the conventional lines. Admittadly the feasibilty is only marginal. If only the works could be brought forward, I would have a much stronger case then.

 

The high speed 1 deployment would allow the 225s to start running at 140 at a much earlier date, giving more 140mph useage and therefore making the money spent on fitting them with ERTMS/ETCS go further, so to speak. This should be enough, the problem might be with insufficent requirements for high speed 1 services or insufficent rolling stock to replace any 225s that move to high speed 1.

 

The timescales sound well out of kilter. The version of ERTMS on the Cambrian (which is basically still only a trial) should, hopefully, now be operational next year, probably.

 

To provide it throughout British mainlines, or even on a single trunk route would not only be a huge task but one which requires development & design to be frozen in order to allow component manufacturing to start. Then the route has to be equipped and the train fleet integration designs (different for every type of train almost certainly) to be developed, tested, approved, and then fitted. Fitting new kit like this into existing trains is never easy and while the work can be scoped and timescaled things can easily go awry once it's found that the real train is 'a bit different from the drawings'.

 

I suspect that if anywhere at all on a mainline route we will first see a proper installation of a finalised UK version of ERTMS on the GWML which is effectively getting into a full route modernisation mode at present (assuming the money doesn't run out) to followed probably by the southern part of the GN mainline as resignalling becomes essential. And I don't think we'll see much beyond the GWML (if it is first) until the late 20teens - and who would then spend money on converting aged IC225 trains (unless any replacement is dropping back at least 10 years)?

[Ron Ron Ron]

.......This is where the bi-mode Super Express falls down, as the electric power is similar to a single HST power car so experts reckon the diesel would have to run most of the time to keep to schedule under the wires.

From what I've read, under electric power, it makes little difference compared with an all-electric train. In an interview with one of the senior engineers on the project (Rail or MR ?), he confirmed that only one electric driving car is needed to supply enough power to the traction package. There is some extra weight to carry in the unused diesel/hybrid generator in one driving vehicle, but this is much lighter than towing a dead loco and offset by the superior performance of the distributed traction package.

Don't forget the fact that the overall weight of the train is much lighter too.

 

That's fast becomming an urban myth and I refer the honoprable gentleman to http://www.agilitytr...eleased-1_5.pdf That's 4MW as against a single HST power car's 2MW or a Class 91's 4.7MW. The distributed traction package (plus lighter overall weight) of the SET means that it will have superior acceleration to the slightly higher rated Class 91 plus MK4's.

I agree it's become an urban myth. Both Hitachi and the IEP project engineers have given enough information on this issue.

 

 

Yet folk that do have a bit of experience/knowledge in this field are still saying it...see Informed Sources in MR Jan, still reckoning the diesel to need to run 30% of the time on electric.

Just saying is all...i'm not the engineer. .....

Unfortunately, even the most respected commentator in MR has the tendency to talk out of his A*** from time to time.

 

This table states that the bi-mode has 4MW on electric power, same as the electric version, and 2MW on diesel. Further down in the same link, it confirms what someone has already posted, that the diesel power car replaces one of the two pantograph/transformer cars. This halves the installed power when running on straight electric.

 

Hence I believe the quoted 4MW is the figure with the diesel running, and much more importantly, the experts quoted in Modern Railways interpret it this way too. Confusing, yes. Intentionally misleading, maybe.

All-electric or Bi-mode, under the wires the 10 car SET is capable of running off one electric driving vehicle.

Even though it is longer than a 225 set, a 10 car SET is lighter and has greater traction capability compared with a 225 (or 125 for that matter).

 

 

So, that clears that up, the bi-mode IEP/SET really would only have half the power, unless running on electrified lines with the diesel fired up as well....

Not at all. A Bi-Mode SET has the same power as an electric SET when under the wires.

Even if it did require part diesel power, the overall saving over the HST it replaces are quite significant.

Those savings are in weight, fuel consumption and economy, faster overall timings, lower emmisions, lower maintenance costs, more reliability, lower track wear etc; at the same time carrying more passengers per train.

Plus SET's in this configuration can be easily converted to all-electric or all-diesel/hybrid by simply exchanging one vehicle and resetting the software.

 

 

p.s. On the subject of train splitting/joining; the IEP specification called for the ability to rapidly carry out these moves, but this involves full or half sets, not individual driving vehicles.

 

 

.

[frobisher]

This table states that the bi-mode has 4MW on electric power, same as the electric version, and 2MW on diesel. Further down in the same link, it confirms what someone has already posted, that the diesel power car replaces one of the two pantograph/transformer cars. This halves the installed power when running on straight electric.

 

That's quite an assumption and very much "diesel thinking". Electric power cars are NOT batteries or generators they are merely the method of current collection. Relatively speaking, without any traction equipment in the mx, the difference in size between a 2MW transformer and a 4MW one is negligable and it would be foolish in the extreme to have a single electric "power car" not be able to provide traction current for the entire train. You'll note that for the electric only version one panatograph is listed as "spare" and whilst there is trasnformer equipment listed in both PCs, this is what is known as "redundancy".

 

Hence I believe the quoted 4MW is the figure with the diesel running, and much more importantly, the experts quoted in Modern Railways interpret it this way too. Confusing, yes. Intentionally misleading, maybe.

 

As I said, "experts" have vested interests. Yes, manufacturers have them too, but Hitachi are currently not on record as saying that the diesel generator will be required to be run under the wires...

 

You'll note that the 5 car bi-mode units only have a listed output of 2MW despite having 4MW available to them "by your reckoning".

[frobisher]

They have probablly never had enough 225s to warrant swaping the locos to extend services beoynd the wires since the electrification was completed along the whole length. In other words they probablly only ordered enough to run the required all-under-the-wires services.

 

So there was a practical, operating consideration for why this was never done then..?

 

Even if that wasn't the case, when running with Mrk3s the 91 couldn't provide power to the coaches so the HST power car had to do this instead. Therefore it may be the case that a HST power car and pretty much any other deisel locomotive wouldn't be able to provide power to Mrk4 coaches.

 

You're confusing two seperate issues. The HST sets do not have a compatible ETH system with normal locomotive hauled stock, hence the requirement when the HST MK3 sets were used with the 91s. The Class 91 and MK4's have pretty much standard ETH. You'd need a seriously powerful diesel to both haul and heat a full MK4 set though.

 

 

Also those SIG bogies were fixed weren't they? by the British? Perhaps.

 

You'll also note that the fixes coincide with the limit to 125mph running...

[The Stationmaster]

That's quite an assumption and very much "diesel thinking". Electric power cars are NOT batteries or generators they are merely the method of current collection. Relatively speaking, without any traction equipment in the mx, the difference in size between a 2MW transformer and a 4MW one is negligable and it would be foolish in the extreme to have a single electric "power car" not be able to provide traction current for the entire train. You'll note that for the electric only version one panatograph is listed as "spare" and whilst there is trasnformer equipment listed in both PCs, this is what is known as "redundancy".

 

 

By definition a power car is a power car, i.e. it powers the train. So perhaps it is the wrong word to use for the IEP 'current collection car'. However I then get a little confused because if there are two of these vehicles instead of one it would surely not increase the available power? All it would seem capable of doing is adding a second point of power collection - a fairly radical departure from any British high speed electric train of the past and one which seems to add pointless cost and redundancy in respoect of what are basically known to be very reliable components. Why on earth cart around a second transformer,it costs money and adds weight (plus creates technical problems if it too happens to have the pan up at the same time as the one on the other 'current collection car').

 

Now I can readily understand that a diesel engine will not have enough poke to fully power all the distributed traction motors so on diesel alone the train performance will be reduced in comparison with one where electric power from the overhead allows more traction motors to be run. So presumably that is where the difference lies - one 'current collection car' can gather enough oomph from the ohle to transform and distribute through the train to get 4mw of driving power, one diesel generating car can only provide enough oomph to produce 2mw of distributed power. But where I run out of understanding is in the need to provide a second 'current collection car' with all the waste that entails?

[frobisher]

By definition a power car is a power car, i.e. it powers the train. So perhaps it is the wrong word to use for the IEP 'current collection car'. However I then get a little confused because if there are two of these vehicles instead of one it would surely not increase the available power?

 

How could it, your available power supply depends upon current running through the overhead line? Hence there are limits on the the numbers of units drawing current within particular track sections on electrified systems. If you go to a 13 amp wall socket, all you can draw is 13 amps. sticking a 4 gang extension into that does not allow you to draw 13 amps from each of those sockets simultaneously as they are being fed from a 13 amp supply. It's as simple as that.

 

All it would seem capable of doing is adding a second point of power collection - a fairly radical departure from any British high speed electric train of the past

 

Especially the APT which had, wait for it two power cars, each with a pantograph, only one of which was actually used at a time and which were connected by a 25KV bus.

 

and one which seems to add pointless cost and redundancy in respoect of what are basically known to be very reliable components. Why on earth cart around a second transformer,it costs money and adds weight (plus creates technical problems if it too happens to have the pan up at the same time as the one on the other 'current collection car').

 

Erm, you have a simple system of interlocks to prevent problems there - plus if you note there is a 25KV bus bar running along the top of the Hitachi SET proposal so I don't think it would actually be a problem in the main part...

 

Given that modern single arm pantographs are "handed", there is doubtless a preferered orientation for running - two pantographs gives you that luxury.

 

Now I can readily understand that a diesel engine will not have enough poke to fully power all the distributed traction motors so on diesel alone the train performance will be reduced in comparison with one where electric power from the overhead allows more traction motors to be run. So presumably that is where the difference lies - one 'current collection car' can gather enough oomph from the ohle to transform and distribute through the train to get 4mw of driving power, one diesel generating car can only provide enough oomph to produce 2mw of distributed power. But where I run out of understanding is in the need to provide a second 'current collection car' with all the waste that entails?

 

It's no more "waste" than having two power cars in the HST - a more efficent system would be to have a single power car (either at one end or in the centre), with a bigger generator. Hitachi would however seem to agree with you in regards the 5 car electric units as these only have a single power car, the other driving trailer having no current collection gear at all, but these are for shorter routes where the risk of failure is more acceptable and more quickly rectified.

[Edwin_m]

if you note there is a 25KV bus bar running along the top of the Hitachi SET proposal so I don't think it would actually be a problem in the main part...

 

I think you are saying that one transformer car can provide 4MW worth of power. This being so why do you need the 25kV bus along the train? It would only be used in the very unlikely event that the pan at one end had failed at the same time as the transformer at the other.

[The Stationmaster]

 

 

Especially the APT which had, wait for it two power cars, each with a pantograph, only one of which was actually used at a time and which were connected by a 25KV bus.

 

(and re my comment about not seeing the point of a second pantograph and transformer arrangement and the problems potentially caused by having two pantographs)

 

Erm, you have a simple system of interlocks to prevent problems there - plus if you note there is a 25KV bus bar running along the top of the Hitachi SET proposal so I don't think it would actually be a problem in the main part...

 

Given that modern single arm pantographs are "handed", there is doubtless a preferered orientation for running - two pantographs gives you that luxury.

 

 

But I still can't see the point of the second pan - the APT was little more than experiment by largely non-rail experienced engineers; all our other high speed electric trains have operated with a single pan for years, in fact the second pan was taken away from many ac electric locos are it was found to be redundant and not needed.

 

Modern pans operate perfectly adequately in both directions at speeds of 180+mph (they do so in everyday service on Eurostars and a huge fleet of TGV and Thalys sets) with no problems beyond the wear rate of the carbons; and their operation, unlike the British situation, includes lowering and raising pantographs at high speed.

[mikeh]

2 MW or 4 MW it's all a bit academic really...

 

This SET nonsense is well on the way to being a dead duck because we can't afford it. The country is bust or hadn't you noticed? Where is the money going to come from? Let's see what happens after the election and the truth emerges, not just the spin as the current lot try and cling to power. Banker's bonuses or new trains - I think I know who's going to get my money - literally!

 

The thrust of Ian Walmsley's article in MR was not about the technical prowess or otherwise of the SET but how much cheaper the loco and stock alternative would be. And this from someone who knows about buying trains.

 

Reading some of the posts above I could almost believe some posters might work for the DfT :icon_wink:

[frobisher]

(and re my comment about not seeing the point of a second pantograph and transformer arrangement and the problems potentially caused by having two pantographs)

 

There is a well known problem with stress on catenary when running two pantographs too close together (and especially at higher speeds) on the same wire - that's what the APT thing was about.

 

But I still can't see the point of the second pan - the APT was little more than experiment by largely non-rail experienced engineers; all our other high speed electric trains have operated with a single pan for years, in fact the second pan was taken away from many ac electric locos are it was found to be redundant and not needed.

 

The second pantograph on the AC electrics was for 6.25KV supply and when this was no longer any form of issue, it was no longer required... Oh, and you did say that no British high speed train ever had two.

 

Modern pans operate perfectly adequately in both directions at speeds of 180+mph (they do so in everyday service on Eurostars and a huge fleet of TGV and Thalys sets) with no problems beyond the wear rate of the carbons; and their operation, unlike the British situation, includes lowering and raising pantographs at high speed.

 

Hence I said "preferred" and "luxury" rather than "necessary". Obviously the aerodynamic drag of a pantograph is overall negligble in the whole picture but for a single arm panto it will present less drag in one orientation than the other - my gut instinct says elbow forward will be better but there may be other factors, but I severely doubt that both orientations will have the same drag characteritics.

[Dagworth]

Various points:

 

Loco changes and timings. Refer to Ipswich, May 85 to May 87. 86s worked from london to Ipswich and then came off to be replaced with 47s for the rest of the journey to Norwich. Timings allowed were 12 minutes on the Up road, and 8 minutes on the Down. I still have timetables somewhere to prove this but know it as I was one of the guys doing those loco changeovers day in and day out. (also seen in model form on Dagworth!)

 

Pantographs on early AC locos were not separate pans for 6.25 Kv and 25 KV, both pans were in parallel. the voltage change was effected by a switch in the transformer. The locos ran with the rear pan raised, the idea being that in the event of a pan being damaged by the OLE the leading pan should have passed under the damaged area unaffected and could then be raised to carry on.

 

APT had the two power cars in the middle of the train because the powers that be in the days when it was built weren't happy with the idea of a 25Kv cable running along the passenger vehicles. As has already been said, high speed running with more than one pan up causes problems with the wire bouncing leading to loss of contact on the rear pan. the french TGV took the opposite approach and allowed the through train 25kv cable.

 

Andi

[The Stationmaster]

There is a well known problem with stress on catenary when running two pantographs too close together (and especially at higher speeds) on the same wire - that's what the APT thing was about.

 

 

Hence I said "preferred" and "luxury" rather than "necessary". Obviously the aerodynamic drag of a pantograph is overall negligble in the whole picture but for a single arm panto it will present less drag in one orientation than the other - my gut instinct says elbow forward will be better but there may be other factors, but I severely doubt that both orientations will have the same drag characteritics.

 

 

Actually the problem with two pantographs occurs when they are widely separated - not when they are close together. That is why the APT adopted the rather peculiar (and operationally expensive) idea of marshalling the power cars together in the centre of the train.

 

And the reason for the problem when the pans are widely separated is that, particularly with BR MK3 ohle, there is a lack of 'rigidity' (for want of a better word) in the contact wire. The passage of the first pan causes the wire to move and thus when the second pan arrives the contact wire can almost be whipping (to the extent that the carrying structures allow).

 

At higher speeds (and I'm not even talking within the BR definition of 'high speed) the oscillation/movement in the contact wire can, in extreme circumstances, result in dewiring the second pan but invariably leads to intermittent loss of contact and damage to the carbons. At high speed things can become dangerous with a very strong risk of dewiring the rear pan or bringing down the catenary.

 

The aerodynamic issue you mention seems to of little impact - it hardly seems to have troubled SNCF. But aerodynamics are an important factor in the design of pantograph heads - mainly to ensure they remain in touch with the contact wire at high speeds without the need for excessive uplift force (which results in much faster carbon wear and can lead to damage to ohle, especially if the ohle is a relatively 'bargain basement' design such as the BR Mk3).

[Ron Ron Ron]

The requirement for multiple pantographs probably reflects the need for redundancy in case of failure, just as there are fewer single system components in the power and traction packages. This isn't unique to the SET but appears to be a feature of most modern express and high speed trains in both mainland Europe and Japan.

 

Far from being "unnecessary waste", I would have thought this sort of built-in redundancy is essential for operation on modern highly utilised railways. If that's at variance with the way of thinking in the days of BR, then so be it; perhaps the "old thinking" is no longer good enough?

 

On the subject of redundancy, I understand that the SET would also carry an auxillary power unit on all versions (electric, self powered and Bi-mode). Apart from providing back up electrical supply, I think the intention is that it will be able to provide emergency power to the traction package to allow the train to "rescue itself" if stranded.

 

 

Multiple Pantographs.

 

I note that the Class 390 Pendolino's have two pantograph vehicles, but I think they only use one of those.

 

DB's ICE 2 and ICE 3 use dual pantographs, sometimes at the same time.

 

I've also noticed that some Continental electric freight locos have 4 panto's !!!

Two of each for dual voltage work perhaps?

 

.

[Fat Controller]

The requirement for multiple pantographs probably reflects the need for redundancy in case of failure, just as there are fewer single system components in the power and traction packages. This isn't unique to the SET but appears to be a feature of most modern express and high speed trains in both mainland Europe and Japan.

 

Far from being "unnecessary waste", I would have thought this sort of built-in redundancy is essential for operation on modern highly utilised railways. If that's at variance with the way of thinking in the days of BR, then so be it; perhaps the "old thinking" is no longer good enough?

 

On the subject of redundancy, I understand that the SET would also carry an auxillary power unit on all versions (electric, self powered and Bi-mode). Apart from providing back up electrical supply, I think the intention is that it will be able to provide emergency power to the traction package to allow the train to "rescue itself" if stranded.

 

 

Multiple Pantographs.

 

I note that the Class 390 Pendolino's have two pantograph vehicles, but I think they only use one of those.

 

DB's ICE 2 and ICE 3 use dual pantographs, sometimes at the same time.

 

I've also noticed that some Continental electric freight locos have 4 panto's !!!

Two of each for dual voltage work perhaps?

 

.

Pendolinos normally run with only one pantograph raised- from what I observed at Euston last week, it would appear to normally be the trailing one.

The four pantographs on some continental locos would be for use under different overhead systems- there are some circumstances where two might be raised; notably starting off under load on a (relatively) low voltage DC network, to reduce the heating effect on the contact strip. The second pantograph would then be lowered when the train is moving- I've noticed French multi-voltage locos do this.

Eurostars run with pantographs raised at both ends, but they're effectively two separate single-ended TGVs working in multiple.

395s regularly run in multiple with one pantograph on each set raised- I suspect, from reading something by Richard Catlow some years ago, that these have to be the ones at either end of the train if the train is to run at line speed.

[edin_bry2x]

There is a well known problem with stress on catenary when running two pantographs too close together (and especially at higher speeds) on the same wire - that's what the APT thing was about.

 

is this the reason that they were running a test train at night on the east coast main line with a set of Mk4s with a 91 at both ends? i did wonder at the time when i seen the pictures what the test was all about.

 

bry

[The Stationmaster]

is this the reason that they were running a test train at night on the east coast main line with a set of Mk4s with a 91 at both ends? i did wonder at the time when i seen the pictures what the test was all about.

 

bry

 

A large amount of test running was done with a Regional Eurostar set in an effort to make it safe to use both pans at speed and there was also high sopeed testing in France with the various pan head designs which were tested as the hoped for solution to the ECML problem. But then I suppose the data from all those tests was probably lost when Eurostar was heavily trimmed some years back. But the French might have kept their copies

 

It's a regrettable result of our method of rail privatisation that things like this have to be done several times over because there is no longer a corporate M&EE and Research organisation.