MML Electrification: progress updates

[GraphitProjekt]

The ATF is all cabled on that stretch. Some time ago, I was fortunate enough to talk with someone involved on ECPSU Phase 1 and he stated that the cabled ATF throughout was used because of the track layout.
On the GWML, MML & WCML (including the Trent Valley section), 1 pair of lines can be closed while the other pair remains open. Similarly, the OLE over those lines and 1 of the 2 ATFs could be isolated to allow work to be undertaken.
GWML:
|DM||UM||DR||UR|

MML/WCML (except Trent Valley):
|DF||UF||DS||US|

WCML (Trent Valley):
|DS||DF||UF||US| - Fast lines are, however, bi-directional

ECML:
|DS||DF||UF||US| - no bi-directional working

With the ECML's track configuration being the way it is, maintenance of the aerial ATF would require more frequent all-line closures.
A side note - as far as I know, the ATs at Welwyn, Langley Junction & Hitchin are operational, but the ones at Corey's Mill are not.

Is there another ATFS feeding Welwyn to Hitchin if the transformers in Corey's Mill aren't in use yet?

 

[chorx18]

Took a return trip from Derby to St Pancras on Friday. Coming back I could see the wooden pegs stretching northwards until somewhere between Sawley Level Crossing and Spondon, so up to about Milepost 122.

 

[WAO]

I think that the "pegs" and the information that Wigston is the (MPATS) boundary for Braybrooke ATFS show that the continuous stretch of route Northwards to Derby etc is under active preparation for wiring. This does not mean it is definite; just that the case is strong enough to invest a million or two in detailed design and surveying, the lack of which has been blamed for the HS2 etc fiascos.

Will Kegworth be a SFC site rather than an ATFS?

WAO

 

[Dazza12]

Hi,

[...]

Will Kegworth be a SFC site rather than an ATFS?

WAO

Given the ready availability of 400kV at Ratcliffe, a SFC is unlikely to be required.

Whether ATFS feeding is required will depend on the length of the sections fed and their anticipated loading.

ATFS and SFC are orthogonal things, one relates to how power is fed along the track and the other relates to how the power is converted between the supply and the track feeding point.

 

[InTheEastMids]

Will Kegworth be a SFC site rather than an ATFS?

I would think that given it's been planned since 2012, it would have been conceived as a conventional supply
Assumption has been that it would connect at a transmission tower (400 or 275 kV) adjacent to the railway, between Ratcliffe on Soar and Kegworth.

Given the ready availability of 400kV at Ratcliffe, a SFC is unlikely to be required.

Agree, the only reason I could think of for changing it is that by shifting to SFC technology that balances the load across all 3 phases (rather than pulling all power from a single phase as traditional transformers do) is that the reduction in imbalance releases capacity for other generation or demand customers to connect (there is an incredibly large pipeline of generation schemes looking to connect to the GB grid at all voltage levels in all locations).

 

[GRALISTAIR]

Hi,

Given the ready availability of 400kV at Ratcliffe, a SFC is unlikely to be required.

I am no expert but I totally agree.

 

[hwl]

Hi,

Given the ready availability of 400kV at Ratcliffe, a SFC is unlikely to be required.

Whether ATFS feeding is required will depend on the length of the sections fed and their anticipated loading.

ATFS and SFC are orthogonal things, one relates to how power is fed along the track and the other relates to how the power is converted between the supply and the track feeding point.

I would think that given it's been planned since 2012, it would have been conceived as a conventional supply
Assumption has been that it would connect at a transmission tower (400 or 275 kV) adjacent to the railway, between Ratcliffe on Soar and Kegworth.


Agree, the only reason I could think of for changing it is that by shifting to SFC technology that balances the load across all 3 phases (rather than pulling all power from a single phase as traditional transformers do) is that the reduction in imbalance releases capacity for other generation or demand customers to connect (there is an incredibly large pipeline of generation schemes looking to connect to the GB grid at all voltage levels in all locations).

The reality is that in the medium term there could be some convergence where you have 132/275/400kV and want a balanced supply:
SFC cost is largely a function of the input and output voltages as the higher the voltage the higher the number of layers of devices. e.g. if using 6.5kV rated IGBT you are limited to 4kV working voltage per layer hence 8 layers on the output side to cover the max OHLE voltage. Higher input voltage is worse for the impact on the number of layers hence you mighty see a hybrid where the supply side mirror new large third rail supplies (e.g. New Cross/Wimbledon) with 400kV to 33KV step down transformer (all 3 phase) but then used to feed a SFC to create +/-25kV for long range feeding in all directions from the supply point.

One interesting possibility is using SFC to do active power factor correction (supply and regen) to reduce rail's impact on Grid supply quality.

SFC is a moving target functionality wise hence why it may have gone a bit quiet.

Some of the new large scale battery storage systems could be set up to help reduce phase imbalances.

 

[GraphitProjekt]

Any indication of where the mid-point substation between kegworth and chesterfield would be? Purely by milage I'd expect the Duffield area

 

[InTheEastMids]

Some of the new large scale battery storage systems could be set up to help reduce phase imbalances.

Thanks for your post - very interesting, only thought I had here was the economics of phase balancing within T&D equipment versus using a battery, which would require NESO to buy a service.

Other thought - NESO TEC register suggests quite a lot of folk are looking at developing batteries adjacent to grid supply points that could tackle imbalance pretty much at the point of origination.
There is a 500 MW battery proposal near Braybrooke, for instance.

 

[WAO]

The reality is that in the medium term there could be some convergence where you have 132/275/400kV and want a balanced supply:
SFC cost is largely a function of the input and output voltages as the higher the voltage the higher the number of layers of devices. e.g. if using 6.5kV rated IGBT you are limited to 4kV working voltage per layer hence 8 layers on the output side to cover the max OHLE voltage. Higher input voltage is worse for the impact on the number of layers hence you mighty see a hybrid where the supply side mirror new large third rail supplies (e.g. New Cross/Wimbledon) with 400kV to 33KV step down transformer (all 3 phase) but then used to feed a SFC to create +/-25kV for long range feeding in all directions from the supply point.

One interesting possibility is using SFC to do active power factor correction (supply and regen) to reduce rail's impact on Grid supply quality.

The Hambleton SFC descriptions seemed to indicate a cost advantage together with higher performance quality (harmonics and power factor) and better line voltage maintenance and feeding distance.

It looks to me that the Potteric Carr SFC has step down transformers (new at the same time), so may indicate a lower input SFC. 400/132/33 transformers will be more "off the shelf" items than xxx/25kV.

A 33kV SFC input would improve the economics of dc/ac conversion as most have a 33kV cable supplying substations.

WAO

 

[hwl]

The Hambleton SFC descriptions seemed to indicate a cost advantage together with higher performance quality (harmonics and power factor) and better line voltage maintenance and feeding distance.

It looks to me that the Potteric Carr SFC has step down transformers (new at the same time), so may indicate a lower input SFC. 400/132/33 transformers will be more "off the shelf" items than xxx/25kV.

A 33kV SFC input would improve the economics of dc/ac conversion as most have a 33kV cable supplying substations.

WAO

So of the cost advantage was slightly disingenuous as they included a change in switchgear regulations at that point in time (reducing the quantity - not just rail but generally applicable including on the grid/DNO) that allowed cost savings so that the % reduction in cost looked bigger (it was still cheaper but not quite as cheap as made out). The reduction in switch gear requirements is seen at Braybrooke on an AT installation.
One of the plus point of SFC is that you can take a standard voltage transformer let the SFC do the rest provided the mismatch isn't to big as that pushed up the quantity of semiconductor devices required and hence cost.
33kV is phase to phase voltage but just ~19kV phase to nominal neutral.

Very new design rolling stock can also address power factor and harmonics issues far which is good for both the train and network - but it reduces the benefit of having and SFC to do it as there is less to do...

Slight deviation: most DC 3rd rail (or DC OHLE upto 3KV in other countries) supplies are 33kV 3 phase (or occasionally 11kV) feeding a pair of transformers with a star and delta configurations and very crude rectification known as a 12-pulse rectifier that produces DC as smooth as the north sea on bad day but is highly reliable, the on board traction electronics happily deal with it though. All the big electronics companies seem to be targeting SFC at AC OHLE rather than DC traction supplies.

== Doublepost prevention - post automatically merged: 17 Mar 2025 ==

Thanks for your post - very interesting, only thought I had here was the economics of phase balancing within T&D equipment versus using a battery, which would require NESO to buy a service.

Other thought - NESO TEC register suggests quite a lot of folk are looking at developing batteries adjacent to grid supply points that could tackle imbalance pretty much at the point of origination.
There is a 500 MW battery proposal near Braybrooke, for instance.

Thinking is moving very rapidly in this area, using battery for phase balancing could be good for everyone - it would indeed need NESO to buy a service but the service could be structured as small discount to charge from the least stressed phase(s) and conversely discharge to the most stressed phase.

And there is huge battery capability going in where the grid feed (via a very long "extension lead") to Marshal Meadows comes from (and the upgrade is in limbo).

 

[Trainman40083]

Any indication of where the mid-point substation between kegworth and chesterfield would be? Purely by milage I'd expect the Duffield area

My understanding was that it would be at Ambergate, where the lines split.

 

[59CosG95]

My understanding was that it would be at Ambergate, where the lines split.

Makes perfect sense to me. If the Matlock line was to be wired as part of the works (unlikely, but we can dream!), it would allow both the branch and the MML to be fed from either side of the proposed Neutral Section (i.e. from Kegworth or Hasland) in the event of one of them going offline for any reason.

Also, with the ATF part of the supply, it makes sense (IMHO) for passively providing power to the Erewash Valley Line, despite the latter's exclusion from the scope of MMLE.

 

[Bald Rick]

There is a 500 MW battery proposal near Braybrooke, for instance.

There’s 1GW going in about 10 miles east at South Kilworth.

 

[Class 170101]

Agree, the only reason I could think of for changing it is that by shifting to SFC technology that balances the load across all 3 phases (rather than pulling all power from a single phase as traditional transformers do) is that the reduction in imbalance releases capacity for other generation or demand customers to connect (there is an incredibly large pipeline of generation schemes looking to connect to the GB grid at all voltage levels in all locations).

Does using all three phases of the Grid mean NR gets more power for its buck so more Electric trains can be operated in the Feeder station's area of operation?

 

[Elecman]

Agree, the only reason I could think of for changing it is that by shifting to SFC technology that balances the load across all 3 phases (rather than pulling all power from a single phase as traditional transformers do) is that the reduction in imbalance releases capacity for other generation or demand customers to connect (there is an incredibly large pipeline of generation schemes looking to connect to the GB grid at all voltage levels in all locations).

Grid Supply Intakes at 132/275/400kV are technically derived from 2 phases not 1. And adjacent supply points are on different phase combinations to try and balance the load over the entire grid

 

[Richard123]

Hi,

Given the ready availability of 400kV at Ratcliffe, a SFC is unlikely to be required.

Whether ATFS feeding is required will depend on the length of the sections fed and their anticipated loading.

ATFS and SFC are orthogonal things, one relates to how power is fed along the track and the other relates to how the power is converted between the supply and the track feeding point.

Not completely; AT supports voltage along route by adding extra conductors, substations and transformers.

SFCs support voltage along route by parallel feeding and controlling supply voltages.

So while SFC plus AT is possible it's unlikely to be necessary.

All of which is academic if NR have already committed £40m+ already on a 400kV supply, connections at that voltage have to be procured many years ahead of the rest of a project.

 

[londonmidland]

This was posted on Facebook this morning.

A screenshot of a Facebook post, showing SPL Powerlines intention to use the compound yard at Syston.

 

[WAO]

33kV is phase to phase voltage but just ~19kV phase to nominal neutral.

Doesn't 33/3 rectify to about 44kV dc?

Good news about Syston compound - "de-vegetation" next!

WAO

 

[59CosG95]

This was posted on Facebook this morning.

They've set up a similar compound at Loughborough, west of the Platform 1 access gate.

 

[Meerkat]

Is it just me that whilst welcoming it finds this stealth electrification a bit weird - wouldn't the companies building these compounds normally be shouting about new contracts etc?

 

[GRALISTAIR]

Is it just me that whilst welcoming it finds this stealth electrification a bit weird - wouldn't the companies building these compounds normally be shouting about new contracts etc?

Possibly. However, I don’t want to get too much into speculative territory but perhaps the government/DfT/HMT have said, please don’t make a fuss and just quietly get on with it.

 

[takno]

Is it just me that whilst welcoming it finds this stealth electrification a bit weird - wouldn't the companies building these compounds normally be shouting about new contracts etc?

If it was fully new business I'd expect the contractor to want to shout about it. If it's just ongoing work then much less so. From Network Rail's point of view it's always better to talk about finished work and tangible outputs.

It's not stealth, it's just business as usual

 

[GraphitProjekt]

It always seems like things go better when there's less media/political attention

 

[Trainbike46]

It always seems like things go better when there's less media/political attention

If the politicians forget a project is happening, they're less likely to interfere. In recent history, political interference has usually brough an increase in costs, a delay, or both.

Then again, no oversight also leads to problems, so a balance must be struck there

 

[sh24]

A low profile, low expectation rolling programme of electrification is exactly what we need. Not unrealistic expectations being dashed against the hard rocks of reality.

 

[GraphitProjekt]

A rolling programme would be great. The way that other countries have been able to electrify so much so cheaply is because instead of building electrification they were building delivery pipelines. That needs an industrial strategy to create the supply chain and training opportunities. If they're so secretive of their intentions then it might be hard for the electrification industry to know how to scale itself.
But i think the bigger question is, how are electrification projects like this one funded at the moment? Is it taken out of control period funding, or does Network Rail approach DfT for a separate fund for each project? In which case, they will always be continually at the mercy of ministers' flights of fancy. I was under the impression that progress is slow at the moment because funding has not being given to proceed any further.

 

[76020]

Here is a Network Rail article about track lowering work at a railway bridge in Barrow Upon Sor near Loughborough this weekend.

Crucial track work near Loughborough affecting London journeys this weekend

Network Rail teams will be carrying out essential track lowering work near Loughborough this weekend as part of wider multi-million-pound Midland Main Line improvements.

www.networkrailmediacentre.co.uk

 

[duffield]

Here is a Network Rail article about track lowering work at a railway bridge in Barrow Upon Sor near Loughborough this weekend.

Crucial track work near Loughborough affecting London journeys this weekend

Network Rail teams will be carrying out essential track lowering work near Loughborough this weekend as part of wider multi-million-pound Midland Main Line improvements.

www.networkrailmediacentre.co.uk

Unlike stuff like pegging out, ground investigations, replacing life expired items with new ones with provision for electrification and so forth, track lowering hardly seems like preliminary or otherwise justified work, more like a serious and expensive part of an actual, approved programme!

If they were rebuilding the bridge, there might be the "excuse" that it was life expired or deficient in some way, but that does not apply for track lowering, which only has one purpose here.

And yet we hear nothing official. Unless somehow this is network rail's cunning plan to slip in so much expensive "prep" work under the radar that they can seriously cut the headline cost of the "actual" electrification?

It's going to look pretty bonkers if further electrification does end up getting cancelled (but it still wouldn't surprise me).

 

[Bald Rick]

But i think the bigger question is, how are electrification projects like this one funded at the moment? Is it taken out of control period funding, or does Network Rail approach DfT for a separate fund for each project?

The latter