Great Western Electrification Progress

[Elecman]

Shame for all those OLE trainees who now won't have a job to go to.

 

[steverailer]

Shame for all those OLE trainees who now won't have a job to go to.

And so the cycle continues, so that when electrification takes off again there will be a lack of skill again!!!!

 

[furnessvale]

And so the cycle continues, so that when electrification takes off again there will be a lack of skill again!!!!

We can only hope that they see sense,continuing a more modest rolling programme that will see bi-modes displaced by straight electrics in due course, the bi-modes moving to other suitable extensions, or even having the engines removed, as required.

 

[SamYeager]

Once again it appears I will probably be proven correct.

I truly am Cassandra... less beautiful though obviously

Slow hand clap. I just hope I don't have to suffer a slew of posts throughout 2017 and beyond of you blowing your trumpet. :cry:

 

[LNW-GW Joint]

And so the cycle continues, so that when electrification takes off again there will be a lack of skill again!!!!

Looks like the GOBLIN team will finish next year (Murphy). I wonder what they will do next?
GW will continue for 4 years or so, NW and the West Midlands for about 2.
Scotland also has several years if they continue their planned programme.
It will be a great shame if, after all the efforts to build teams up, they are let go again.
HS2 is still a fair way away from OHLE work, and is a different kind of project.

I was also reading in MR of the start of the run-down of the TfL Crossrail team, currently tunnellers and designers.
HS2 and Crossrail 2 are too far off to reabsorb them yet.

 

[gareth950]

There's still announcements to be made regarding Swansea and Valley lines electrification...........
(Well, I can hope)

 

[LNW-GW Joint]

There's still announcements to be made regarding Swansea and Valley lines electrification...........
(Well, I can hope)

I think there's a good chance that modest urban schemes, sponsored by PTEs and the like, will survive and be developed.
They can be bog-standard 100mph max lines using Series 2 design.
I suppose the key to South Wales is the Cardiff-Swansea stretch (which needn't be the expensive 140mph Series 1 design).

 

[Dave1987]

In the January edition of MR in Roger Fords' column, there is a comment about a MP questioning why Selby-Hull electrification has been canned. The Transport Secretarys' response was the TOCs have ordered bi-modes so there was no need to electricify.

How can anyone now deny that bi-modes are now killing electrification? It's just far far too easy to cancel projects but still give passengers those shiny new trains. I doubt that GW electrification will be completed.

 

[Class 170101]

Can't remember if it was this thread or elsewhere on this board but I did say that Bi-modes will only get you so far. Nevermind the fact fuel prices are on the way up again.

Cancelling the electrification despite NRs faults is extremely short sighted.

 

[gareth950]

In the January edition of MR in Roger Fords' column, there is a comment about a MP questioning why Selby-Hull electrification has been canned. The Transport Secretarys' response was the TOCs have ordered bi-modes so there was no need to electricify.

How can anyone now deny that bi-modes are now killing electrification? It's just far far too easy to cancel projects but still give passengers those shiny new trains. I doubt that GW electrification will be completed.

There's no need for bi-modes to give passengers shiny new trains - straightforward DMUs can also give passengers shiny new trains with no electrification needed at all and DMUs are hardly new inventions are they? So it can't be solely the fault of bi-modes that electrification projects are not being completed.

 

[Dave1987]

There's no need for bi-modes to give passengers shiny new trains - straightforward DMUs can also give passengers shiny new trains with no electrification needed at all and DMUs are hardly new inventions are they? So it can't be solely the fault of bi-modes that electrification projects are not being completed.

Well all the evidence I'm reading seems to suggest that bi-modes are the biggest factor in it all. It seems they currently trying to negate the performance issues with the lack of wires and extended running on diesel. The language like 'bi-modes can bring benefits for passengers without disruptive engineering works' seems like they are going for the easier PR scoops. Yet some were suggesting the bi-mode would encourage them to electrify quicker, hmmm that's been proven complete bull!

More quotes;'given that the number of passenger benefits already being delivered without electrification', "there is almost no further benefit to justify further publicly funded investment and the disruption electrification would bring".

Bi-modes are killing electrification, pure and simple.

 

[LNW-GW Joint]

It's about 15 years since ATOC/RDG said passengers couldn't tell the difference between diesel and electric trains, and NR (John Armitt, no less) said electrification was "just another interface to go wrong".
DfT kept on about hydrogen fuel cells obsoleting electrification overnight.
And all before bi-modes appeared.

 

[jimm]

Bi-modes are killing electrification, pure and simple.

If only they'd done what you told them to do and just slung up the wires - even, apparently, on parts of the GWR network where the economics of doing so were dubious to non-existent without other lines being wired as well - and then ordered some non-existent off-the-shelf UK-gauge electric express trains once the wiring was done, then all would have been just fine and dandy...:roll::roll::roll:

 

[TheKnightWho]

Well all the evidence I'm reading seems to suggest that bi-modes are the biggest factor in it all. It seems they currently trying to negate the performance issues with the lack of wires and extended running on diesel. The language like 'bi-modes can bring benefits for passengers without disruptive engineering works' seems like they are going for the easier PR scoops. Yet some were suggesting the bi-mode would encourage them to electrify quicker, hmmm that's been proven complete bull!

More quotes;'given that the number of passenger benefits already being delivered without electrification', "there is almost no further benefit to justify further publicly funded investment and the disruption electrification would bring".

Bi-modes are killing electrification, pure and simple.

So why do they want to electrify anything at all? This is a question you have still yet to answer, despite being asked it many, many times.

 

[doa46231]

If only they'd done what you told them to do and just slung up the wires - even, apparently, on parts of the GWR network where the economics of doing so were dubious to non-existent without other lines being wired as well - and then ordered some non-existent off-the-shelf UK-gauge electric express trains once the wiring was done, then all would have been just fine and dandy...:roll::roll::roll:

The point is WHY are the economics 'dubious' in Britain when virtually everywhere else there does not seem to be a problem?

 

[SamYeager]

Bi-modes are killing electrification, pure and simple.

Of course it has nothing at all to do NR's programme management, ORR refusing to allow applications for derogations from the more onerous rail safety standards not to mention incomplete plans of existing cables all leading to massive budget overruns. Politicians always look for ways to turn a sow's ear into a silk purse and claim the credit.

It seems my unwanted Christmas present is to see your one eyed posts on this subject over the coming year(s). :cry:

 

[HSTEd]

So why do they want to electrify anything at all? This is a question you have still yet to answer, despite being asked it many, many times.

Because what bi-modes do is not kill electrification per se, they simply destroy the network effect.

However the effect will be much the same since almost all areas with high enough traffic densities to justify electrification without the network effect are effectively completed.

Maybe the MML if you are lucky but I somewhat doubt it.
After that the electrification programme is dead as a dodo.

 

[NotATrainspott]

Because what bi-modes do is not kill electrification per se, they simply destroy the network effect.

However the effect will be much the same since almost all areas with high enough traffic densities to justify electrification without the network effect are effectively completed.

Maybe the MML if you are lucky but I somewhat doubt it.
After that the electrification programme is dead as a dodo.

I don't think so. Most of the lines in and around the north of England would be unsuitable for bi-modes and increasingly unsuitable for DMUs with increasing passenger numbers. Bi-mode trains without overhead wires are just heavier, more expensive DEMUs, which in themselves aren't really any better than standard DMUs. They're only useful when they spend a long time on intensively-worked electrified mainlines, as all of the Hitachi bi-modes ordered yet far will be doing every day. The Stadler units are a bit of an oddity but Stadler seem keen on their own self-powered concept, so it's hardly surprising that they stuck a pantograph on top of trains which won't spend long under the wires.

There's still a network effect in that straight EMUs will still be cheaper and easier to manage than a fleet of bi-modes. For instance, electrification to Kirby and Ormskirk from the non-Liverpool direction is unlikely to be worthwhile in isolation, but once you've done all the other lines in the area you may as well just get the job done. This is especially so when these services wouldn't be self-contained for efficiency's sake, as having a whole fleet capable of bi-mode operation just for the sake of a branchline or two would be quite a waste.

The cost and complexity of electrification can and will be brought down by judicious use of the enhanced battery technologies being used in road vehicles in the next decades. Onboard batteries need only be as large and powerful as required to get across the biggest impediment to electrification on a route. 80% of the electrification can be done for 20% of the cost and difficulty, at which point you would be mad not to electrify all the lines you possibly can. While the clearances used on Paisley Canal might not be permissible any more, the concept of doing wiring on the cheap through inventive engineering and management should be here to stay.

 

[HSTEd]

I don't think so. Most of the lines in and around the north of England would be unsuitable for bi-modes and increasingly unsuitable for DMUs with increasing passenger numbers.

Taking the North of England as a model it is difficult to think of large numbers of DMU diagrams that do not spend a significant amount of time under overhead wiring.
Most of the inner suburban networks of most of the major cities are electrified already and thus most DMU diagrams operating out of them operating significant under wires.

Bi-mode trains without overhead wires are just heavier, more expensive DEMUs, which in themselves aren't really any better than standard DMUs.

DEMUs are probably the future however - the upsides in the face of an intensively worked railway seem to be telling now.
And since they are probably only a few percent more expensive if you turn them into electrodiesels will likely militate against building any more pure diesel units.

They're only useful when they spend a long time on intensively-worked electrified mainlines, as all of the Hitachi bi-modes ordered yet far will be doing every day. The Stadler units are a bit of an oddity but Stadler seem keen on their own self-powered concept, so it's hardly surprising that they stuck a pantograph on top of trains which won't spend long under the wires.

Well the existance of the Stadler units demonstrate that bi-modes are apparently economic with relatively little electric operation.
Pending advances in traction converters will also significantly reduce the weight and cost penalty of 25kV electric capable units by shrinking the transformer drastically.

There's still a network effect in that straight EMUs will still be cheaper and easier to manage than a fleet of bi-modes.

But a full fleet of electrodiesels will be easier to manage than a mixed fleet of electric and diesel units.

For instance, electrification to Kirby and Ormskirk from the non-Liverpool direction is unlikely to be worthwhile in isolation, but once you've done all the other lines in the area you may as well just get the job done. This is especially so when these services wouldn't be self-contained for efficiency's sake, as having a whole fleet capable of bi-mode operation just for the sake of a branchline or two would be quite a waste.

It should be noted that SNCF has decided not to purchase any more diesel units now that it has bought electrodiesel units.
They are doing precisely what you believe to be uneconomic.
But the point I am trying to make is that almost none of the surrounding routes will ever be electrified. Only the very high traffic density ones will be - especially given the escalting cost of electrification.
And none of the surrounding unelectrified routes are particularily high density.

The cost and complexity of electrification can and will be brought down by judicious use of the enhanced battery technologies being used in road vehicles in the next decades.

So your plan to reduce the cost of electrification.... is not to electrify most of the network?

 

[jimm]

The point is WHY are the economics 'dubious' in Britain when virtually everywhere else there does not seem to be a problem?

The lines I am referring to are the likes of the Cotswold Line and Swindon-Gloucester/Cheltenham, where there are frequent (and going to be more frequent with IEP) GWR services to and from London - but where electrification is not going to be viable until other wiring happens, such as Birmingham-Worceser and Birmingham-Bristol, allowing most of the services in Worcestershire and Gloucestershire to convert to electric traction - it is never going to be cost-effective to wire just for the GWR express services.

I don't know why you think other countries don't have a problem with the cost of electrification in some places. The French have a lot of bi-mode regional trains in service, now being joined by some long-distance sets, because there are places that they can't yet justify wiring work either.

DEMUs are probably the future however

Really? Does your amazing crystal ball know what the oil price is going to be in 10 or 20 years' time? Thought not - if it goes back to where it was not very long ago then electrification suddenly becomes a whole lot more attractive again.

 

[cjmillsnun]

Really? Does your amazing crystal ball know what the oil price is going to be in 10 or 20 years' time? Thought not - if it goes back to where it was not very long ago then electrification suddenly becomes a whole lot more attractive again.

The cost of fuel is already going up again. Even if oil prices remain stable, I suspect the pound is going to continue to fall relative to other currencies as Brexit kicks in. Electrification is going to look more attractive again when this happens. Hopefully the lessons learned from other projects can be applied making electrifying other lines cheaper and faster.

 

[GRALISTAIR]

Really? Does your amazing crystal ball know what the oil price is going to be in 10 or 20 years' time? Thought not - if it goes back to where it was not very long ago then electrification suddenly becomes a whole lot more attractive again.

The cost of fuel is already going up again. Even if oil prices remain stable, I suspect the pound is going to continue to fall relative to other currencies as Brexit kicks in. Electrification is going to look more attractive again when this happens. Hopefully the lessons learned from other projects can be applied making electrifying other lines cheaper and faster.

Exactly. You don't electrify when the price of oil is >100 because you are then in a mad scramble to do it quickly etc. you make hay while the sun shines. So although the business case is not as good electrify while oil is circa 40$ and so when it hits 100$ you are fully prepared.

 

[steverailer]

The cost and complexity of electrification can and will be brought down by judicious use of the enhanced battery technologies being used in road vehicles in the next decades. Onboard batteries need only be as large and powerful as required to get across the biggest impediment to electrification on a route. 80% of the electrification can be done for 20% of the cost and difficulty, at which point you would be mad not to electrify all the lines you possibly can. While the clearances used on Paisley Canal might not be permissible any more, the concept of doing wiring on the cheap through inventive engineering and management should be here to stay.

This is from a bog standard linesman's point of view who's been working on this project.

The cost could be lowered by:

1. Disposing of some of the HOPS train sections, and letting conventional get on with the job. Too much time is lost at each end of a shift due to getting it in and out for the actual work it does, but because of its original cost and status it HAS to go out regardless.

2. When a section is to be done, go in in advance and get more RRV access points so the teams lose less travel time to the work location, this will payback on the actual construction and improve future maintenance as well.

3. Don't over spec the design. Are we actually ever going to see 140 mph? Do we need such large structures? Is it really necessary to have the high wire tensions over such a short wire run compared to elsewhere in the country?

4. Cut back the bureaucracy, each team has to send a report into at least 10 different people at the end of each shift stating what they have done and why they have not done something. The organisation is too top heavy, and not enough listening to the guys on the ground. Let the lads on the ground use some common sense to when it comes to installing, some of these guys have been doing this work for years, use that experience !!!

5. Let each discipline complete their works on a section before the next comes in, there is too much overlap of work, i.e sps being installed before steel has completed the location (tightening bolts or installing a strut) and then the SPS that has been installed is in the way of the steel machines getting to finish the job.

6. Install things correctly first time. Its seems that there is a rush for box ticking that things have been installed, sometimes this means that you are told to 'just put it up/in and we'll come back and sort it later'. This adds extra cost each time that location is returned to to 'sort it later', and frustrates the lads as they would rather do a job once that come back several times. Yes, the bosses get the numbers installed they are after, but the snagging takes a lot longer than it ever should.

Will any of this ever change? I very much doubt it, to be honest I can only see it getting worse.

 

[LNW-GW Joint]

This is from a bog standard linesman's point of view who's been working on this project.

Very interesting observations.
If I remember correctly you have also worked on the NW project (Series 2)?
I know that project had its problems in the early stages (probably still does!), but did it feel like a better managed project than GW?
NW (and probably EGIP) is more typical of the electrification programmes to come than the GW project with its quadruple track and 140mph spec.

I get the impression that clearance design issues and local authority permits have cost all the projects dear, irrespective of the construction issues.

I wonder what NR will say to the Goring Gap mafia when they review the completed installation as promised?
I can't see much "prettification" rework being sanctioned.

 

[steverailer]

Very interesting observations.
If I remember correctly you have also worked on the NW project (Series 2)?
I know that project had its problems in the early stages (probably still does!), but did it feel like a better managed project than GW?
NW (and probably EGIP) is more typical of the electrification programmes to come than the GW project with its quadruple track and 140mph spec.

I get the impression that clearance design issues and local authority permits have cost all the projects dear, irrespective of the construction issues.

I wonder what NR will say to the Goring Gap mafia when they review the completed installation as promised?
I can't see much "prettification" rework being sanctioned.

This project is a lot better managed than the NW was, but that's because Balfours aren't involved. From what I've heard from others the part that they are doing is just as bad as the NW was. It all depends on the managers though, I understand the Maidenhead to Reading is a different beast (more chaotic) to Reading westwards , both managed by Amey but different section managers.

 

[HSTEd]

Really? Does your amazing crystal ball know what the oil price is going to be in 10 or 20 years' time? Thought not - if it goes back to where it was not very long ago then electrification suddenly becomes a whole lot more attractive again.

The long term price of oil is fixed by the operating price of the swing supplier - which for the next couple of decades will be American Light Tight Oil.

And that is going to be something like $50-60/bbl.
And getting cheaper. Tar sands might even become the swing supplier with SAGD becoming economic about $60.

 

[Taunton]

ORR refusing to allow applications for derogations from the more onerous rail safety standards

We have always suspected that some of the more academic standards imposed are just a result of bureaucrats triumphing over reality, but can our correspondents identify any specific items which ORR or their acolytes have turned down.

Regarding the bi-modes, I suppose it was only to be expected that the UK rail industry would embrace something designed to work with a job half done. Electrification, in this case.

 

[NotATrainspott]

Taking the North of England as a model it is difficult to think of large numbers of DMU diagrams that do not spend a significant amount of time under overhead wiring.
Most of the inner suburban networks of most of the major cities are electrified already and thus most DMU diagrams operating out of them operating significant under wires.

A good number of the line in and around the North are natural candidates for electrification. Hills, tight curves (making acceleration/deceleration more important), reasonably closely spaced stops and a lot of people who'll need to commute into busy city centres makes a compelling case for traditional electrification. Once these lines are done, the lines left can plausibly be electrified for the sake of making the network simpler to run. For instance, once the Atherton line is done and linked to electrified Caldervale services, it would be grossly inefficient to rely upon a huge bi-mode fleet for the sake of not extending the wires to Kirkby/Skelmersdale.

DEMUs are probably the future however - the upsides in the face of an intensively worked railway seem to be telling now.
And since they are probably only a few percent more expensive if you turn them into electrodiesels will likely militate against building any more pure diesel units.

A considerable chunk of the benefit of electrification boils down to making things simpler and lighter, which bi-modes can't do. You might have improved acceleration using distributed electric traction but you won't have the reduced mass which multiplies that effect.

Well the existance of the Stadler units demonstrate that bi-modes are apparently economic with relatively little electric operation.
Pending advances in traction converters will also significantly reduce the weight and cost penalty of 25kV electric capable units by shrinking the transformer drastically.

But a full fleet of electrodiesels will be easier to manage than a mixed fleet of electric and diesel units.

ICEC aren't getting a full fleet of bi-mode IEPs. There's still an additional upfront and ongoing cost involved in taking around more diesel engines than are actually required. The trains can be designed in a modular fashion so that the bi-modes are simply the electric-only units with diesel engines added on, but then most of the difficulty of having two separate fleets disappears.

It should be noted that SNCF has decided not to purchase any more diesel units now that it has bought electrodiesel units.
They are doing precisely what you believe to be uneconomic.
But the point I am trying to make is that almost none of the surrounding routes will ever be electrified. Only the very high traffic density ones will be - especially given the escalting cost of electrification.
And none of the surrounding unelectrified routes are particularily high density.

The area around the North West is pretty ideal for electrification. It's hardly rural and it's only a short distance away from major city centres with employment and other attractions to generate lots of traffic.

So your plan to reduce the cost of electrification.... is not to electrify most of the network?

Where did you get that idea from? The idea is to avoid the most expensive parts of electrification, so that the money can instead be spent on wiring up more plain-line route. For instance, a big chunk of the cost of wiring up the Wigan-Kirkby/Skelmersdale line will be getting electrification clearnace under the WCML just west of Wallgate station. With batteries, such clearance would never be required, as trains could drop their pans at the platform, go under the bridge using battery power alone and then raise the pan again when the wires return. Electrifying a plain-line route is almost always easy; it's when you have low bridges or old tunnels or hard-to-electrify stations that the costs really pile up. The battery solution could also neatly decouple electrification from track changes and remodelling works, as it wouldn't be necessary to wait until all of them are done before the wires can be installed. The short unelectrified sections can be returned to when the time is right and the resources are available to do it properly.

 

[HSTEd]

A good number of the line in and around the North are natural candidates for electrification. Hills, tight curves (making acceleration/deceleration more important), reasonably closely spaced stops and a lot of people who'll need to commute into busy city centres makes a compelling case for traditional electrification.

However most of the un-electrified sections of these routes are run at relatively low traffic densities. A tiny handful of vehicles per hour is not a good case for electric operation given the now enormous cost of the capital.
The trunks of these routes might justify electrification but with bi-modes unless an entire route justifies it there is little reason to do so.

For example the Buxton Line already has the benefits of electric operation as far as Hazel Grove but the remaining section is not heavily enough operated (and is unlikely to ever be so) to justify electrification on its own merits. As there is now effectively no fuel saving credit for eliminating under wires running.

Once these lines are done, the lines left can plausibly be electrified for the sake of making the network simpler to run. For instance, once the Atherton line is done and linked to electrified Caldervale services, it would be grossly inefficient to rely upon a huge bi-mode fleet for the sake of not extending the wires to Kirkby/Skelmersdale.

Why would you need a huge bi-mode fleet. We have mixed electric and diesel fleets now. You would simply have a mixed electric and bi-mode fleet.
Additionally why would you electrify the Atherton line? It is relatively lightly trafficked and bi-modes would enable you to use the electrification between Salford Crescent and central Manchester.
Two short DMUs an hour is not a business case. Traffic would have to treble or more before it starts to look reasonable.

A considerable chunk of the benefit of electrification boils down to making things simpler and lighter, which bi-modes can't do. You might have improved acceleration using distributed electric traction but you won't have the reduced mass which multiplies that effect.

The weight of the diesel engine-generators is pretty negligible however, they weigh less than the passengers do. The primary saving of electrification is the reduction in use of the engine with fuel and maintenance savings. A diesel engine that only runs half the time will require considerably less maintenance than one that hs to be used all day every day.
And energy from electricity remains considerably cheaper than from diesel, even with current low fuel prices.

ICEC aren't getting a full fleet of bi-mode IEPs. There's still an additional upfront and ongoing cost involved in taking around more diesel engines than are actually required. The trains can be designed in a modular fashion so that the bi-modes are simply the electric-only units with diesel engines added on, but then most of the difficulty of having two separate fleets disappears.

Thus enabling a mixed fleet of bi-modes and electrics. Which rather demolishes your argument that total electrification would be pursued to eliminate the electrodiesel subfleet.

The area around the North West is pretty ideal for electrification. It's hardly rural and it's only a short distance away from major city centres with employment and other attractions to generate lots of traffic.

It's not that good. It has numerous lightly trafficked routes going in various directions that mean that you get terrible utilisation on the overhead wiring equipment.
If there was one line between Manchester and Liverpool with branches off of it it would have been electrified in the 60s - but because the traffic was spread over several it could never justify it.

Where did you get that idea from? The idea is to avoid the most expensive parts of electrification, so that the money can instead be spent on wiring up more plain-line route. For instance, a big chunk of the cost of wiring up the Wigan-Kirkby/Skelmersdale line will be getting electrification clearnace under the WCML just west of Wallgate station. With batteries, such clearance would never be required, as trains could drop their pans at the platform, go under the bridge using battery power alone and then raise the pan again when the wires return. Electrifying a plain-line route is almost always easy; it's when you have low bridges or old tunnels or hard-to-electrify stations that the costs really pile up.

What's the difference between this and simply using a diesel engine instead of a battery?
You are proposing to electrify only those parts of the network that can justify it on their own merits.
However you seem to be suggesting that electrifying short sections on a route with gaps in between is a good idea - that just makes me think of horrifying numbers of pans getting ripped off on bridges or having their ADDs triggered because they are going up and down like a yo-yo.

When faced with the threat of so many delay minutes the operators will just opt to use diesel engines instead.
To be honest a return to 6.25kV or even 1500V would be more economic than discontinuous electrification - even with the insane EU requirements the clearance would be far smaller.

 

[NotATrainspott]

However most of the un-electrified sections of these routes are run at relatively low traffic densities. A tiny handful of vehicles per hour is not a good case for electric operation given the now enormous cost of the capital.
The trunks of these routes might justify electrification but with bi-modes unless an entire route justifies it there is little reason to do so.

For example the Buxton Line already has the benefits of electric operation as far as Hazel Grove but the remaining section is not heavily enough operated (and is unlikely to ever be so) to justify electrification on its own merits. As there is now effectively no fuel saving credit for eliminating under wires running.

It is in the nature of commuter rail systems to branch and branch as they get further away from the city centre until you're left with 2tph or less. A naive look at number of carriages per hour on a section of track would make you think that it wouldn't be worth wiring up these sections. However, if you only wire up the trunk, every single train would have to carry around a diesel engine anyway, significantly reducing the value of the electrified section. This reduction in value is reasonable on busy mainline routes like the GWML where bi-modes off of the very long rural branches will then need to act as high-capacity units on the mainline core. On a branching suburban network the additional weight, cost and complexity of bi-modes has to be considered against the idea of just saving the money on electrifying the trunk in the first place, as you could plausibly run the entire network unelectrified and save the capital cost of doing anything.

Why would you need a huge bi-mode fleet. We have mixed electric and diesel fleets now. You would simply have a mixed electric and bi-mode fleet.

Because you just said:

But a full fleet of electrodiesels will be easier to manage than a mixed fleet of electric and diesel units.

I'm arguing that you can have a mixed electric/bi-mode fleet, but that's only possible if you use bi-modes sparingly on branch line routes alone. With the argument you had above, you wouldn't be able to have any electric-only units, as eventually every line gets to the point where electrification isn't worth it.

Additionally why would you electrify the Atherton line? It is relatively lightly trafficked and bi-modes would enable you to use the electrification between Salford Crescent and central Manchester.
Two short DMUs an hour is not a business case. Traffic would have to treble or more before it starts to look reasonable.

Look at it. It's an unelectrified suburban route connecting two important electrified areas. It has closely spaced stops and is a feeder route into a major city. The reason why electrification isn't currently planned for it is that then there wouldn't be a balance across Manchester, so services would have to inefficiently terminate in the city centre rather than running through. It's like the Whifflet Line up in Glasgow, which has now been successfully folded into the electrified Argyle Line network despite having only a 2tph short DMU service beforehand. Wiring it up gave another electrified diversionary route for mainline traffic (the Whifflet wiring was designed for 11-car Pendolinos).

Electric operation of a bi-mode set is not a tick-box exercise, and using the wires only after Salford Central would be a pointless tick-box exercise. At that point, you may as well just run a mechanical DMU all the way.

The weight of the diesel engine-generators is pretty negligible however, they weigh less than the passengers do. The primary saving of electrification is the reduction in use of the engine with fuel and maintenance savings. A diesel engine that only runs half the time will require considerably less maintenance than one that hs to be used all day every day.
And energy from electricity remains considerably cheaper than from diesel, even with current low fuel prices.

A diesel engine that doesn't exist needs even less maintenance than one that's used half of the time.

Thus enabling a mixed fleet of bi-modes and electrics. Which rather demolishes your argument that total electrification would be pursued to eliminate the electrodiesel subfleet.

ICEC's fleet does thousands of route miles each day, covering an amount of track which would be totally unfeasible to electrify quickly within the age of the trains. The suburban network around Manchester or another Northern city is a different issue altogether.

It's not that good. It has numerous lightly trafficked routes going in various directions that mean that you get terrible utilisation on the overhead wiring equipment.
If there was one line between Manchester and Liverpool with branches off of it it would have been electrified in the 60s - but because the traffic was spread over several it could never justify it.

Possibly so, but passenger use of the railways is changing and in a direction which lends itself to electrification. More and more people want to head into city centres from suburban stations. When routes are improved, passenger numbers grow and we're seeing little sign of that changing any time soon.

What's the difference between this and simply using a diesel engine instead of a battery?
You are proposing to electrify only those parts of the network that can justify it on their own merits.
However you seem to be suggesting that electrifying short sections on a route with gaps in between is a good idea - that just makes me think of horrifying numbers of pans getting ripped off on bridges or having their ADDs triggered because they are going up and down like a yo-yo.

When faced with the threat of so many delay minutes the operators will just opt to use diesel engines instead.
To be honest a return to 6.25kV or even 1500V would be more economic than discontinuous electrification - even with the insane EU requirements the clearance would be far smaller.

The fundamental difference is that this battery isn't there to get a train all the way up from Hazel Grove to Buxton, but to get it under a low bridge without coasting. The cost of wiring up a route could be slashed by doing this, making it economical to wire up lines that wouldn't be otherwise. It wouldn't be practical to have long neutral sections under bridges near stations or signals today because trains wouldn't be able to coast through, so you have to go to the expense of raising the bridge and/or lowering and rebuilding the station. This size of battery could be a standard fit across an entire EMU fleet and require none of the special equipment and maintenance needed by diesel power packs (e.g. refuelling roads, engine shops, emissions controls). If there's mechanical clearance for the pantograph but not the necessary electrical clearance then you just need to splice in a non-electrified section of wire so that the pantograph is always pushing against something.