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Author Topic: Great Western Main Line electrification - ongoing discussion  (Read 684846 times)
drandles
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« Reply #135 on: August 29, 2009, 05:42:46 pm »

My fear is that they will decide that stopping the wires at Newbury will be an excuse to buy loads of expensive bi-mode IEP trains.  I'd much rather that we had a few years of a few deisels under the wires than bi-mode trains cos once they are delivered they will be arround for 40 years and act as a disincentive to expand electrification duringtheir life.

I fear the same. Also note the ECML, and the fact that bi mods will be used on services beyond Leeds and Edinburgh.

Although the whole train is correctly referred to as 'bi-mode', in fact 9 of the 10 cars (or 4 of the 5) are exactly the same build as the full electric version. So they don't have to be around for 40 years in the as delivered condition, as long as further electric end cars can be built.  I think it is important to remember that the diesel end isn't really a 'power car' like in an HST, it is just a generator car for the distributed traction on the rest of the train, ie it cannot move on its own.  Even the full diesel IEP is really an 8 car EMU, sandwiched between its two diesel generator cars.

Paul

Unfortunately, as I understand, the performance of the bi-mode IEP when in diesel mode will be significantly inferior to present day HSTs, so that services worked by these trains are likely to be slower than present day services. While this may not matter for short extensions from eg Bristol to Weston or Swansea to Carmarthen, it becomes a more serious issue for Newbury-Penzance or Oxford-Hereford, or Swindon-Cheltenham.  So I anticipate that Devon and Cornwall will continue to be served by HSTs for many years. The all diesel version of the IEP has apparently been dropped.

Incidentally, I am told that the plan is to use bimode IEPs on a semi-fast service from Paddington to serve Hungerford, Bedwyn and probably Pewsey and Westbury. On the other hand, it seems that electrification from Newbury to Bedwyn in the inital phase  is not entirely ruled out.

A further downside of the electrification plan is that the new dmus for the Bristol area which were due to enter services from 2011-12 have also been cancelled and it will now be 2017-18 or so before any significant improvements are made to the Cardiff-Bristol-Portsmouth services, using second hand turbos from the Thames Valley.

David
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willc
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« Reply #136 on: August 29, 2009, 06:38:46 pm »

One important factor missing from this debate is the role of freight. A lack of infill electrification is a major hindrence to FOCs moving away from diesel haulage. It's no surprise that no new electric freight locos have been built since the introduction of the Class 92s in the early 1990s. Electrification that solely benefits passenger operations will cause major pathing issues for FOCs with their reliance on diesel traction.
The former chairman and owners of EWS (possibly the largest of the FOC's) had a policy of diesel traction, DB Schenker may have a different view after all the FOC's need to make their case and a commitment to use electrification, which I am sure they will.

I think you can take it for granted the Germans in particular will back wider use of electric traction where possible. The latest issue of rail says that DB Schenker is taking over haulage of Stobart Rail trains from DRS and will use Class 92s on the Daventry-Scotland services.
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eightf48544
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« Reply #137 on: August 30, 2009, 11:10:10 am »

Ian Walmsley writing in September's Modern Railway suggests what he calls a "schizo-Voyager" basically a Voyager with additonal panto graph/transformer car for running  electric under the wires and diesel off the wires. Given their over provision of power the addition of another 40 tonnes of train weight hardly dents the HP/tonne ratio on diesel. Plus there would be more seats or perhaps reinstate the buffet.

He reckons it would be 5 better overall from Bristol to Penazance with 13*90 second stops and 5 at Plymouth, than the current 225 minutes for an 8 car HST. Whereas an IEP bi mode would be 8 worse.

On a further question, if suitable balises were fitted could Super Voyagers tilt in Cornwall?

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paul7755
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« Reply #138 on: August 31, 2009, 04:53:26 pm »

Another snippet from Roger Ford's column in Sept Modern Rail is that electrification of the Severn Tunnel will use rigid bar conductor. The firm he mentioned is Furrer & Frey, if you look down this page of their 2007 news:
http://www.furrerfrey.ch/web/furrerfrey/en/news/news-2007.html
...there is an item about Sunderland North tunnel, this is where NR replaced the previous system with rigid bar because there were corrosion issues with the previous OHLE, which only dated from the Sunderland extension, somewhat less than ten years.  I think the same kit is used in the recently electrified tunnels between Waverley and Haymarket.

Paul
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« Reply #139 on: August 31, 2009, 07:27:12 pm »

Another snippet from Roger Ford's column in Sept Modern Rail is that electrification of the Severn Tunnel will use rigid bar conductor. The firm he mentioned is Furrer & Frey, if you look down this page of their 2007 news:
http://www.furrerfrey.ch/web/furrerfrey/en/news/news-2007.html
...there is an item about Sunderland North tunnel, this is where NR replaced the previous system with rigid bar because there were corrosion issues with the previous OHLE, which only dated from the Sunderland extension, somewhat less than ten years.  I think the same kit is used in the recently electrified tunnels between Waverley and Haymarket.
Paul
The rigid bar system is used on the Trowse Bridge (Norwich) (image from Wikipidia) when it was electrified in the 80's  A swinging cantilever system using the rigid conductor was installed in North Pole Depot to allow the road that was used for lifting could also be used for normal maintenance.
From what the OLE design engineers has told be the plan is to install portal type structures inside Seven Tunnel to support the contact system, also classic Booster Transformer or return conductor system will be used where as the rest of the GWML will be Auto Transformer system.  There are train speed limitations with rigid contact equipment
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willc
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« Reply #140 on: September 01, 2009, 12:03:37 am »

These limitations would be what exactly? The Furrer & Frey system has been tested up to 260kmh (that's 161mph for all those who seem to think using metric measurements is some kind of sinister European plot) in a tunnel in Austria, as I pointed out more than a year ago, when several people were busy insisting that the Severn Tunnel could never be electrified.
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paul7755
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« Reply #141 on: September 01, 2009, 11:44:22 am »

Getting back to rolling stock...

Based on a quick skim of the GWML RUS draft I linked to earlier, the bi-mode trains will be pairs of 5 cars, with splitting and joining. If this is the correct interpretation it seems to remove the problem of underpowered trains off the wires, but with the knock on effect of the 10 car train only having 8 x 26m passenger coaches...

This supports something I posted a while back, where I pointed out that the initial plans for IEP had most of the 10 car bi-mode trains on the ECML...

Paul
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willc
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« Reply #142 on: September 01, 2009, 07:19:04 pm »

Section 8.7 of the RUS, starting on page 165 lays out a potential programme of future wiring for the region.
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Electric train
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« Reply #143 on: September 01, 2009, 08:59:31 pm »

These limitations would be what exactly? The Furrer & Frey system has been tested up to 260kmh (that's 161mph for all those who seem to think using metric measurements is some kind of sinister European plot) in a tunnel in Austria, as I pointed out more than a year ago, when several people were busy insisting that the Severn Tunnel could never be electrified.
Not sure that a rigid OHLE contact system has been used in the UK at any thing approaching high speed.  I've never seen the Seven Tunnel as an impossible to electrify it is quite a large diameter tunnel a little damp in places but not the wettest of tunnels that have had 25kV run through them and lets face it 25kv runs through carriage washing plants  Grin

Furrer & Frey is the system being used to rewire the GE between Liverpool St and Shenfield / Southend, having seen some of it in the sky it looks a bit light weight compared to it predecessor but apparently it is performing very well.
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drandles
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« Reply #144 on: September 02, 2009, 07:42:12 am »


Unfortunately, as I understand, the performance of the bi-mode IEP when in diesel mode will be significantly inferior to present day HSTs, so that services worked by these trains are likely to be slower than present day services. While this may not matter for short extensions from eg Bristol to Weston or Swansea to Carmarthen, it becomes a more serious issue for Newbury-Penzance or Oxford-Hereford, or Swindon-Cheltenham.  So I anticipate that Devon and Cornwall will continue to be served by HSTs for many years. The all diesel version of the IEP has apparently been dropped.

David

After some further reading, I have to correct myself here. It seems that a 2x5car IEP bi-mode train working on diesel will have much higher power at the rail (2x2MW) than a 2+8 HST (1x1.3MW) so that there should be no performance loss compared with present day services. Moreover there is very little performance difference on electric between the bi-mode and all electric versions which have the same power at the rail, although the bi-mode unit is slightly heavier and has fewer seats.
David


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onthecushions
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« Reply #145 on: September 02, 2009, 11:28:03 am »

Having digested both the facts and learned arguments put forward about GW Electrification, my conclusions are:

1. It's the rolling stock, stupid.

2. New diesels aren't viable, replacement stock is (if it's electric).

3. Modernish emu's are cascadable for lives of at least 50 years (like HST's!).

4. Diesels under the wires are doubly wasteful, when they are needed elsewhere.

5. No one knows what to do when the wires end. This is what bothers people most.

I suspect that we'll end up with the new all-electric IEP's being hauled by the class 67's, beyond the wires. There are 30 of them, looking for a home, can put down about 1.9MW at rail and have high top speed if they can reach it. They are however only BoBo and weigh in at only 88t - could they climb the Devon banks?

For the 319's, either we terminate at Turbo shuttles beyond Oxford, Newbury and Swindon or use Turbos under the wires when they are needed elsewhere. The class 210 power car comes idly to mind....

( http://www.anteater.freeuk.com/MUgallery/demu/210oxf.htm)

All this is a long time ahead of course.

OTC

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grahame
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« Reply #146 on: September 02, 2009, 12:14:16 pm »

Having digested both the facts and learned arguments put forward about GW Electrification, my conclusions are:

4. Diesels under the wires are doubly wasteful, when they are needed elsewhere.

All this is a long time ahead of course.


Can I take it that you also consider weekday diesel services that are on 3rd rail lines throughout are also wasteful ... and that would apply equally from next May as from 'a long time ahead'?   I'm trying to get my head round the logic of transferring the 158 that's been running the morning TransWilts to Swindon servivce  onto the Lymington branch.
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FlyingDutchman
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« Reply #147 on: September 02, 2009, 01:22:20 pm »

I would like to see the electrification extended to Exeter from Bristol.

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paul7755
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« Reply #148 on: September 02, 2009, 01:28:36 pm »

After some further reading, I have to correct myself here. It seems that a 2x5car IEP bi-mode train working on diesel will have much higher power at the rail (2x2MW) than a 2+8 HST (1x1.3MW) so that there should be no performance loss compared with present day services.

Have you seen this David?

http://www.agilitytrains.com/assets/pdf/AT-090205-Key_Facts-Released-1_5.pdf Hitach Data Sheet

I think I may have posted it before, but it gives all the figures needed. You seem to have worked out (as I did) that the 'power problems' are really only applicable to a 10 car bi-mode.

Paul
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paul7755
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« Reply #149 on: September 02, 2009, 01:54:59 pm »

I would like to see the electrification extended to Exeter from Bristol.



It will be eventually, as far as Plymouth, according to the earlier NR electrification strategy. IIRC it is one of the phases of the XC NE/SW route, to follow on from Bromsgrove - Bristol.  Once it is done they intend to do Newbury - Taunton, which will allow Paddington - Plymouth. 

In other words the business case comes more from XC pax than locals.

Paul
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