Great Western IEP order - Are there too many Bi-modes ?

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PhilipW

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The order for Great Western IEPs is 21 electric 9-car trains (189 carriages) and 36 bi-mode 5-car trains (180 carriages). No electric 5-car trains have been ordered.

My initial assessment is that too many bi-mode trains have been ordered at the expense of electric versions.

Looking at the routes in turn:

Cardiff/Swansea with a service every 30 mins to Cardiff and one of the services proceeding onwards to Swansea to give it an hourly service.
A Paddington-Cardiff-Paddington turnround with appropriate layovers takes 5 hours requiring 5 train sets.
A Paddington-Swansea-Paddington turnround with appropriate layovers takes 7 hours requiring 7 sets making 12 sets in total. If we add another set to allow for a more frequent Swansea service in the peaks, this gives a requirement of 13 electric 9-car sets.
Taking also into account the 1 per day through service past Swansea to West Wales, this adds the need for one bi-mode 5-car set. Assuming that it will run as 10-car Swansea-Paddington this requires a second 5-car set which could be an electric set, though none have been ordered.

Bristol with a service every 15 mins via either Bath or Parkway.
A Paddington-Bristol-Paddington turnround can be done in 4 hours with appropriate layovers. This gives a requirement for 16 (4x4) sets. If we assume that one service an hour is extended to Weston-Super-Mare which will have to be a 5-car bi-mode, this reduces the Bristol requirement of electric sets to 12.
So already the core Cardiff/Swansea/Bristol service will require 25 sets (13 plus 12) which is more than the total of electric sets on order (21).
The Weston service will require 5, possibly 6, bi-modes plus the sets (4) to be detached at Temple Meads. Again these could be electric but none are on order. I am assuming platform lengths will stop 10-car sets running onwards to Weston.

So the full Weston/Bristol/Swansea/cardiff service requires 25 electric 9-car sets plus 12 bi-mode 5-car sets of which 5 could have been all electric.

The Hereford/Worcester service probably requires 7 bi-mode sets and the Gloucester service 6 sets, all restricted to single sets because of platform lengths.

These figures are all approximate and I'm sure some will disagree with the detail. The overall point I am trying to make is that I think the order is short of electric sets and has too many bi-mode sets. Having about 5 more 9-car electric sets, or 10 more 5-car electric sets, with a equivalent reduction of bi-modes looks a better fit to me. Switching 10 bi-mode sets to electric (50 carriages) saves 50 x £400,000 (equals £20 million) in construction costs alone plus running expenses. Big money.
 
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D365

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Are you sure you got some of your maths right? And did you take into account that electrifiction has (if I've read it correctly) been extended to Swansea. Unless you're thinking about services to the west.
 

150001

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It will be better to have too many bi mode trains than too many electrics. Bi modes can run under electric power just like any other and this provides flexibility on the diesel only parts. I don't really see any problem with too many of the bi modes
 

rail-britain

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The order for Great Western IEPs is 21 electric 9-car trains (189 carriages) and 36 bi-mode 5-car trains (180 carriages). No electric 5-car trains have been ordered.
What about the Exeter / Plymouth / Penzance services?
I would assume Bi-Mode will be required for these
This then gives flexibility to swap on to Cardiff / Swansea services
 

PhilipW

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What about the Exeter / Plymouth / Penzance services?
I would assume Bi-Mode will be required for these
This then gives flexibility to swap on to Cardiff / Swansea services

None of this order of IEPs is planned for the West Country services. These services all remain HST for the present. The DfT has not published plans for any replacement for these HSTs yet.
--- old post above --- --- new post below ---
Are you sure you got some of your maths right? And did you take into account that electrifiction has (if I've read it correctly) been extended to Swansea. Unless you're thinking about services to the west.

Yes, I think I have done the maths correctly and I have taken into account that electrification is being extended to Swansea.

13 sets required for Cardiff/Swansea service
12 sets required for the 3 services per hour that terminate at Bristol.
This gives a requirement for 25 electric 9-car sets of which only 21 have been ordered.

The 12 set requirement for Bristol is only that low because I am assuming that one service per hour will carry on to Weston or Taunton.
 
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mallard

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Having "too many" bi-modes is sensible, even if they mostly spend their time "under the wires". It adds flexibility for engineering diversions, allows introduction into service before the wiring is complete, future expansion of services, etc.
 

JamesRowden

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My guess would be that this order was formed before the confirmation of electrification to Swansea (and so does not include enough electric sets).
 
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None of this order of IEPs is planned for the West Country services. These services all remain HST for the present. The DfT has not published plans for any replacement for these HSTs yet.

I wonder if Electrification of the core cross country route goes ahead in CP6 then could the Bi modes used for services to and Gloucester and Cheltenham be replaced with 5 car electric IEP if Swindon to Stonehouse was electrified as well? The Bi modes freed up could then be used for services to the South West .
 

hwl

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My guess would be that this order was formed before the confirmation of electrification to Swansea (and so does not include enough electric sets).

DfT will have known about Swansea electrification for a while. The number of electric sets has been increased and bi modes decreased since the previous set of proposals so this is probably not the case.

My guess is that the IEPs will start to operate 3 years before full electrification of all the currently publicly planned routes is complete so a greater number of bi-modes will be required initially than are required at full electrification.

I suspect that some journeys will use bi-mode in electric only mode for the whole journey when the current electrification works are complete.

There is an option to purchase more IEPs for the west country routes. If we assume no further electrification, it might be that this would be a mixed order of electric and bi-mode, with the new electrics used to cascade some of the original bi-modes to the west country.

As a thought The Swindon - Kemble and North Cotswold lines redoubling projects will increase lines speeds and reduce journey times significantly and hence the number of units required to operate the service. Did the thread starter take this (and the timetable recast in general i.e. reduced Bristol journey time by x minutes) into account when assessing the number of bi-modes (or electrics) needed?
 

sprinterguy

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My guess would be that this order was formed before the confirmation of electrification to Swansea (and so does not include enough electric sets).
Incorrect, the number of electric IEP sets for the Great Western has been increased since the Great Western franchise consultation was published, in line with the more recent announcement of electrification to Swansea.
--- old post above --- --- new post below ---
My guess is that the IEPs will start to operate 3 years before full electrification of all the currently publicly planned routes is complete so a greater number of bi-modes will be required initially than are required at full electrification.
If the present deadlines for both IEP delivery and GWML electrification are adhered to, then this will not be the case. The full length of the GWML will be electrified at the time that the IEPs enter service.
 

PhilipW

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As a thought The Swindon - Kemble and North Cotswold lines redoubling projects will increase lines speeds and reduce journey times significantly and hence the number of units required to operate the service. Did the thread starter take this (and the timetable recast in general i.e. reduced Bristol journey time by x minutes) into account when assessing the number of bi-modes (or electrics) needed?

I attempted to. I certainly took into account the published new ferequencies, more difficult to calculate is the allowed layover times at Paddington, Swansea and Bristol. I accept that my numbers could be tweeted, either up or down, but I do believe the general thrust is valid.

The service to Weston seems to raise the most questions. I presume the TOC will want to run a 10-car train to Bristol, then decouple one of sets to run on to Weston. As it stands at the moment both sets will have to be bi-mode as no 5-car electrics have been ordered. To run an hourly service will require 9 or 10 sets, 4 just running to/from Bristol where they will be detached and await the next train from Weston to attach to and return to Paddington. These 4 sets will be running "under the wires" 100% of the time. Because they will be bi-mode they will have cost £2 million extra each set to build (5 times £400,000 per carriage)and have greater running costs and poorer performance under the wires. So getting the correct electric/bi-mode balance is in everyone's interest. I am far from convinced that we have it right.
 
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YorkshireBear

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Later order of electrics to displace bi modes to me sounds like a much better idea than removing diesels from bi modes to make them electric. Something i think that now swansea is being done will happen.
 
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Because they will be bi-mode they will have cost £2 million extra each set to build (5 times £400,000 per carriage)and have greater running costs and poorer performance under the wires.
If they have poorer performance under the wires, they will be outside of the IEP specification which requires them to match the all electric version.
 

PhilipW

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If they have poorer performance under the wires, they will be outside of the IEP specification which requires them to match the all electric version.

Interesting. My knowledge is not that technical so I am not in a position to discuss this in any detail. However I shall look forwards to Roger Ford's technical comments in the next edition of 'Modern Railways' to see what he has to say. He certainly has been very critical of the performance of bi-modes in the past.

As bi-modes are heavier than all electrics because they have a big diesel plus fuel to carry around, this surely must mean that their electric components would have to operate to a higher standard if they are to match the performance of an all electric train. While anything is possible, that does seem rather unlikely to me.
 

tbtc

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Having "too many" bi-modes is sensible, even if they mostly spend their time "under the wires". It adds flexibility for engineering diversions, allows introduction into service before the wiring is complete, future expansion of services, etc.

It will be better to have too many bi mode trains than too many electrics. Bi modes can run under electric power just like any other and this provides flexibility on the diesel only parts. I don't really see any problem with too many of the bi modes

I agree with both of you - no harm in this way round (very dodgy to have it the other way round)

I wonder if Electrification of the core cross country route goes ahead in CP6 then could the Bi modes used for services to and Gloucester and Cheltenham be replaced with 5 car electric IEP if Swindon to Stonehouse was electrified as well? The Bi modes freed up could then be used for services to the South West .

My hunch is that as each line gets electrified the business case for further electrification increases, so a bi-mode IEP on Gloucester services could be replaced by a fully electric IEP, with the bi-mode unit moving to a service like XC or the South West ones that you mention. The bi-modes then get cascaded round the country as each route is electrified (e.g. they could do London - Sunderland, then when that's electrified move onto London - Holyhead...)
 

LE Greys

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And of course there's always the option for a follow-up order of straight-electric units to allow some electro-diesels (my opinion on the term 'bi-mode' is well-known) to cascade to Laira to replace the remiaining HSTs (Laira seems the natural place to keep them). I can't really see a small pool of HSTs surviving that long just for one route.
 

Mystic Force

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How much do passengers weigh? Well according to wikipedia the average UK citizen is 84.0 kg so if we look at the weight of an engine quoted as 1.2 tonnes in another thread. That equals 14.3 passengers. It would have to be a very terrible train if it could not stick to a diagram because there were 14 extra passengers in each coach.
 

John55

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How much do passengers weigh? Well according to wikipedia the average UK citizen is 84.0 kg so if we look at the weight of an engine quoted as 1.2 tonnes in another thread. That equals 14.3 passengers. It would have to be a very terrible train if it could not stick to a diagram because there were 14 extra passengers in each coach.

I think you are in danger of being the victim of a female lynch mob if you suggest the average UK adult is 84kg. Try 77kg which allows for the average weight of the female population at 70kg.

Your point is valid. If you allow 1900kg for an engine (from a different other thread), 500kgs for an alternator and 2000kg for a fuel tank the extra weight of the diesel gubbins is less than that of the passengers in a full coach.
 

swt_passenger

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If they have poorer performance under the wires, they will be outside of the IEP specification which requires them to match the all electric version.

Correct. Roger Ford explained all this last June (2011), basically that the change to underfloor engines, combined with the decision taken NOT to order or build any 10 car bi-modes meant that the performance under the wires issue was negated.

Only the 10 car bi-mode had this problem, because it did not have space for enough transformer power for full electric operation, and this meant the diesel engine would be needed under the wires, but that was on the original spec, the one with an end power car for the diesel engine, and a single transformer car at the other end.

Just to emphasise again, the problem would not have occured with the 5 car bi-modes as originally offered anyway.
 

Erniescooper

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I think you are in danger of being the victim of a female lynch mob if you suggest the average UK adult is 84kg. Try 77kg which allows for the average weight of the female population at 70kg.

Your point is valid. If you allow 1900kg for an engine (from a different other thread), 500kgs for an alternator and 2000kg for a fuel tank the extra weight of the diesel gubbins is less than that of the passengers in a full coach.

The engine raft in a 180 weighs 3200kg "wet"(this does not include transmission), the cooler group weighs 2100kg "wet" and it has a 2500 litre fuel tank. As your trying to get similar performance out of 3 engines in 10 car train those engines, cooler groups and fuel tanks are going to have to be very very big and 3 pretty big generators as well.
 

LE Greys

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How much do passengers weigh? Well according to wikipedia the average UK citizen is 84.0 kg so if we look at the weight of an engine quoted as 1.2 tonnes in another thread. That equals 14.3 passengers. It would have to be a very terrible train if it could not stick to a diagram because there were 14 extra passengers in each coach.

I think you are in danger of being the victim of a female lynch mob if you suggest the average UK adult is 84kg. Try 77kg which allows for the average weight of the female population at 70kg.

Your point is valid. If you allow 1900kg for an engine (from a different other thread), 500kgs for an alternator and 2000kg for a fuel tank the extra weight of the diesel gubbins is less than that of the passengers in a full coach.

Allow the extra few kilos for luggage, food, etc (except when I'm carrying a case that's half my weight). Plus extra fuel to carry the extra weight.
 

WatcherZero

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Correct. Roger Ford explained all this last June (2011), basically that the change to underfloor engines, combined with the decision taken NOT to order or build any 10 car bi-modes meant that the performance under the wires issue was negated.

Only the 10 car bi-mode had this problem, because it did not have space for enough transformer power for full electric operation, and this meant the diesel engine would be needed under the wires, but that was on the original spec, the one with an end power car for the diesel engine, and a single transformer car at the other end.

Just to emphasise again, the problem would not have occured with the 5 car bi-modes as originally offered anyway.

That was negated when they increased the transformer capacity from 3mw to 3.4mw.
 

jimm

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In answer to to the initial post, any assumptions about IEP deployment should have taken into account the considerable increase in portion working proposed with IEP to enhance frequencies.

This is how Gloucester/Cheltenham and the Cotswold Line to Worcestershire are supposed to go to hourly off-peak London services throughout the day, while ensuring adequate seating capacity between London and Oxford/Swindon using 2x5-car formations.

If you were to couple a 5-car bi-mode on the front of a 5-car electric set out to Swindon or Oxford that's fine on paper, so long as nothing goes wrong, but if the bi-mode develops a fault, then the train will immediately be cancelled once the wires run out, whereas if both are bi-modes then both have the ability to continue the journey.

The number of bi-modes ordered is an operational necessity, not a luxury. And if enhanced frequencies bring yet more passengers, you may want to increase those frequencies yet again, but you wouldn't be able to do that with all-electric sets unless and until wires go up. Note that the Cotswold Line timetable has seen a series of extra services steadily added over the years since the early 1990s when there was a switch to through running to and from London most of the day and success has bred more success, with the route now enjoying its most frequent service ever.
 

PhilipW

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In answer to to the initial post, any assumptions about IEP deployment should have taken into account the considerable increase in portion working proposed with IEP to enhance frequencies.

Fair points you make for Gloucester and Worcester. Point taken.

If you reread my initial post you will see that one of my main points was that the 21 electric 9-car sets will be hard pushed to satify all the Swansea/Cardiff/Bristol diagrams where no portion working is required. I estimated those journies as requiring 25 sets, and that with assuming that 1 of the 4 Bristol journies per hour would be 2 x 5-car bi-mode because of extending one 5-car to Weston.

...... now if only the 20 miles to Weston was electrified too ..... it would make such a difference to the required fleet composition.
 

anthony263

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Fair points you make for Gloucester and Worcester. Point taken.

If you reread my initial post you will see that one of my main points was that the 21 electric 9-car sets will be hard pushed to satify all the Swansea/Cardiff/Bristol diagrams where no portion working is required. I estimated those journies as requiring 25 sets, and that with assuming that 1 of the 4 Bristol journies per hour would be 2 x 5-car bi-mode because of extending one 5-car to Weston.

...... now if only the 20 miles to Weston was electrified too ..... it would make such a difference to the required fleet composition.

I have to agree with you about wiring to Weston Super Mare maybe the Severn Beach branch along with the line to Portishead if it is re-opened.

Hopefully these will be done in CP6
 

Martin222002

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There won't be any double 5 car formations running off peak. The DfT has been quoted as saying "the planned use of 5 car sets enables affordable off peak frequencies to be increased." In over words Operation Princess Mk2.

My best guess is that the 9 car electrics will work the Swansea, Cardiff and Bristol via Bath services, with the Bristol via Parkway, Cheltenham, Worcester/Great Malvern/Hereford, Westbury/Exeter/Paignton semi-fast services using the 5 car bi-modes off peak.
 

swt_passenger

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There won't be any double 5 car formations running off peak. The DfT has been quoted as saying "the planned use of 5 car sets enables affordable off peak frequencies to be increased." In over words Operation Princess Mk2.

My best guess is that the 9 car electrics will work the Swansea, Cardiff and Bristol via Bath services, with the Bristol via Parkway, Cheltenham, Worcester/Great Malvern/Hereford, Westbury/Exeter/Paignton semi-fast services using the 5 car bi-modes off peak.

As you say, a best guess, and your own interpretation of what DfT have said may be completely wrong anyway, as it doesn't actually rule out at least some 10 car trains, as written.

It seems that IEP semi-fast services on the Westbury/Exeter/Paignton route have not been mentioned explicitly at all, in either of last week's announcements, ie including the IEP and GW ITT.

Portion working of IEPs beyond Oxford would be far more like SWT's Waterloo - Bournemouth - Weymouth service, and no-one ever seems to refer to that as an 'Operation Princess Mk 2', presumably because it is known to work properly...
 

jimm

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There won't be any double 5 car formations running off peak. The DfT has been quoted as saying "the planned use of 5 car sets enables affordable off peak frequencies to be increased." In over words Operation Princess Mk2.

Presumably you don't spend much time riding on off-peak services between Oxford and Paddington, which start or end their journeys at Worcester or Malvern, where adding/dropping Turbos at Oxford has been going on to varying degrees ever since 1993, to help match capacity to passenger numbers on the legs of journeys east and west of Oxford.

Setting aside whatever may happen on Bristol and South Wales off-peak services, the DfT quote relates to plugging the gaps that exist in current off-peak timetables to the likes of Worcester/Malvern and Gloucester/Cheltenham and being able to do this rather more cheaply than running HSTs full of empty seats off-peak west of Oxford/north of Swindon.

When FGW first got rid of 180s in 2008-9 it tried HSTs on most Cotswold Line services but soon took fright at the costs set against revenue outside the peak periods and brought back Turbos on most off-peak services. These are now giving way to 180s again - as long as they stop breaking down - and there are a number of services where a lone 180 will clearly struggle to cope with the loadings between Oxford, Reading and London but splitting/joining 180 formations isn't an option due to the lengthy process involved, whereas IEP is designed to make this straightforward.

A suggested track layout for a redesigned Oxford station included in the 2010 Great Western RUS by Network Rail has scissor crossovers, which would appear intended to assist with portion working. See page 248 at http://www.networkrail.co.uk/browse...trategies/great western/great western rus.pdf
 

CC 72100

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Bristol via Parkway, Cheltenham, Worcester/Great Malvern/Hereford, Westbury/Exeter/Paignton semi-fast services using the 5 car bi-modes off peak.

This worries me slightly. How many Plymouth/Penzance services will remain? If it is a case that there will still be an hourly HST from Pad to Plymouth or Penzance, then that is fine. (8 coaches an hour through exeter is fine)

However, if you were to run a HST to Plymouth and Penzance every 2 hours, with an Exeter service the other hour (so 14:06 PAD - EXD, 15:06 PAD - PLY etc.) then I'd be a little concerned with overcrowding on that. (5 coaches an hour to Exeter seems a bit tight)

At this stage however we can only try and guess how the timetables will work, and what the service frequency will be like, and I'll admit that I haven't done much reading into the subject, although if it was as I've written in the second paragraph, I would be slightly concerned.
 

swt_passenger

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At this stage however we can only try and guess how the timetables will work...

You seem to be asking about frequencies, not the actual timetable, so you could always follow the links to the DfT website in the GW ITT thread:

http://www.railforums.co.uk/showthread.php?t=69167

It's the 'train service requirement' that you need.

In any case, as I posted earlier, they haven't mentioned anything about IEPs ruunning on the B&H at all...
 
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