Short (under 15 miles) lines that would be useful to electrify

[Triang Hornby]

Micklefield to Hambleton Jct

 

[Uncle Buck]

Barrhead to Kilmarnock is an obvious one for me. If the GSW line services were run from Carlisle - Kilmarnock - Ayr connecting with electric services Kilmarnock to Glasgow, it could eliminate all regular DMU services into Central (I am aware that additional electric units are required for this service and the odd East Kilbride services still in the hands of 156s)

I was going to suggest this too but to my surprise this was further than fifteen miles. I would also think that residents of Dumfries would rather have a direct connection to Glasgow than to Ayr, if Ayr can still be accessed by changing at Kilmarnock?

I’d add the Maryhill Line and the gap between Maryhill and Westerton. This could open up new service patterns in north Glasgow. At any rate it would remove diesel from the Glasgow suburban network.

 

[Farigiraf]

It prevents having a microfleet of battery trains.

GWR need battery trains for:
- Windsor, Henley, Greenford, Marlow, Reading-Basingstoke
- MetroWest
- Devon Metro
- Gunnislake, Looe, Newquay, Falmouth, St Ives

Wouldn't call that a microfleet.

 

[The Planner]

Except that some XC trains run via the Camp Hill line, which is not electrified – and they all use the also not-electrified fast lines between Kings Norton and Longbridge. So it isn't quite as simple as subtracting the time at Bromsgrove from the time at Proof House Junction and saying they are under the wires for all that time!

Fast lines are getting electrified as part of Midlands Rail Hub, as for Camp Hill you deal with the reversal on the Manchesters and go via Selly Oak.

 

[Mgameing123]

GWR need battery trains for:
- Windsor, Henley, Greenford, Marlow, Reading-Basingstoke
- MetroWest
- Devon Metro
- Gunnislake, Looe, Newquay, Falmouth, St Ives

Wouldn't call that a microfleet.

The turbo's are kind of a Microfleet in the Reading area compared to the Electrostars.

 

[zwk500]

GWR need battery trains for:
- Windsor, Henley, Greenford, Marlow, Reading-Basingstoke
- MetroWest
- Devon Metro
- Gunnislake, Looe, Newquay, Falmouth, St Ives

Wouldn't call that a microfleet.

The Thames Valley, WECA area, Devon metro, and Cornish branches would likely be operated as mostly independent fleets.

However I agree that the number of BEMUs that would be required to be based in the Thames Valley, Bristol Area, Exeter area, and Plymouth/Penzance would on themselves be sufficient as to be beyond a microfleet.

 

[Zomboid]

It's 3 units required for Basingstoke now Green Park is open, isn't it? So assuming the e electric trains are no faster than turbos, that'd be 7 for the Thames Valley, plus whatever is needed for Bedwyn and Oxford. Probably looking at around 12-15 to be kept in the area including a couple of spares - certainly not a microfleet overall if they're the same trains as used in the other areas.

Though without some wiring being added to what's there now it's unlikely that the units would be able to have their pans up enough to last a whole day of shuttling. I don't know at what point the whole thing would fall into "just do the job properly and use proper electric trains" territory.

 

[Farigiraf]

It's 3 units required for Basingstoke now Green Park is open, isn't it? So assuming the e electric trains are no faster than turbos, that'd be 7 for the Thames Valley, plus whatever is needed for Bedwyn and Oxford. Probably looking at around 12-15 to be kept in the area including a couple of spares - certainly not a microfleet overall if they're the same trains as used in the other areas.

Though without some wiring being added to what's there now it's unlikely that the units would be able to have their pans up enough to last a whole day of shuttling. I don't know at what point the whole thing would fall into "just do the job properly and use proper electric trains" territory.

If you're electrifying strategically, you'd get wires up past Newbury as well as to Oxford by the time BEMUs come in. Battery units are far better suited for branch lines than intercity corridors.

IMO it's a better use of resources to electrify all the way to Penzance via both Westbury and Bristol, as then the branch line BEMUs could charge up from the mainline power, meaning you wouldn't need charging islands at every terminal station (as at West Ealing) which would bring costs down more in the long term. Plus the intercity routes could go all electric, of course.

 

[zwk500]

So assuming the e electric trains are no faster than turbos

I think it is a very safe assumption that any new BEMUs would be quite a bit faster than Turbos.

, that'd be 7 for the Thames Valley, plus whatever is needed for Bedwyn and Oxford. Probably looking at around 12-15 to be kept in the area including a couple of spares - certainly not a microfleet overall if they're the same trains as used in the other areas.

Though without some wiring being added to what's there now it's unlikely that the units would be able to have their pans up enough to last a whole day of shuttling. I don't know at what point the whole thing would fall into "just do the job properly and use proper electric trains" territory.

Oxford certainly does (it's already got 387s waiting to take over the service and a bi-modes that'd benefit), Basingstoke probably does (2tph + potential for bi-mode freight to use electric mode). The Branches less so. bedwyn on it's own wouldn't justify a project to finish it off but OLE out to Westbury/Castle Cary and potentially on to Taunton or Exeter might be able to make a case if the IETs were looking to replace gensets with battery packs.

 

[Zomboid]

think it is a very safe assumption that any new BEMUs would be quite a bit faster than Turbos

With the pan up, sure. But there will be a performance/ range/ battery lifespan compromise that will need to be made on routes like those in the Thames valley where a pretty small proportion will be on electrified sections. They might actually end up only matching the turbos.

Reading to Basingstoke and Didcot to Oxford are both sections of trunk routes and should justify having the job done properly. It's not imminent but Bi modes will come to XC as well, which will be able to make use of both sections.

 

[zwk500]

With the pan up, sure. But there will be a performance/ range/ battery lifespan compromise that will need to be made on routes like those in the Thames valley where a pretty small proportion will be on electrified sections. They might actually end up only matching the turbos.

I think they'd have to be extremely conservative to get equal performance to a Turbo from a new BEMU, even in end-of-life condition. I would expect all Thames Valley branches to have the bay platforms electrified and a length up the branch suitable for shunting in and out if the battery plays up.
I would expect normal operation to be only to raise and lower the pan when stationary though.

Reading to Basingstoke and Didcot to Oxford are both sections of trunk routes and should justify having the job done properly. It's not imminent but Bi modes will come to XC as well, which will be able to make use of both sections.

I agree on both counts. Even if a BMMU cascade to XC is quite a long way off.

 

[Farigiraf]

Reading to Basingstoke and Didcot to Oxford are both sections of trunk routes and should justify having the job done properly. It's not imminent but Bi modes will come to XC as well, which will be able to make use of both sections.

At Basingstoke you'd have the issue of having both OHLE and 3rd rail in the same station. Then the question of whether it's worth converting the third rail network to OHLE arises.

To make use of electric power in as many places as possible, a new XC intercity unit would require pantographs, batteries, third rail shoes as well as a diesel engine as a backup. A highly complex ask for any train manufacturer.

 

[Zomboid]

agree on both counts. Even if a BMMU cascade to XC is quite a long way off.

The key thing with those sections (also Sheffield to Derby, though possibly to a lesser extent) is that there are services running today which would benefit, and in future the benefits will multiply further.

== Doublepost prevention - post automatically merged: 24 Apr 2026 ==

At Basingstoke you'd have the issue of having both OHLE and 3rd rail in the same station. To make use of electric power in as many places as possible, a new XC intercity unit would require pantographs, batteries, third rail shoes as well as a diesel engine as a backup. A highly complex ask for any train manufacturer.

If batteries are deployed then you can forget the diesel. If the battery can't be relied upon in situations which can be forseen then it shouldn't be used at all.

And dual voltage traction goes back many decades. It would be a bit more complex than a two mode train, but DC BEMUs and AC BEMUs will be a thing in the not too distant future, so this isn't a reinvention of the wheel.

 

[zwk500]

At Basingstoke you'd have the issue of having both OHLE and 3rd rail in the same station.

At Basingstoke it would be easy to keep the OLE into Platform 5 and not have an extremely short un-electrified crossover keeping the DC separate. AC and DC are a serious issue if on the same track, but if kept isolated from each other then even on parallel tracks they're much less of a problem for each other.

To make use of electric power in as many places as possible, a new XC intercity unit would require pantographs, batteries, third rail shoes as well as a diesel engine as a backup. A highly complex ask for any train manufacturer.

I imagine that by the time XC are being ordered new units, fitting them with internal combustion gensets will be banned. The 777s are capable of being fitted with 3rd Rail + Pan or 3rd rail + battery, it's only space that prevents all 3 being fitted at the same time. XC units would presumably be long enough to solve that issue.

 

[Zomboid]

Basingstoke it would be easy to keep the OLE into Platform 5 and not have an extremely short un-electrified crossover keeping the DC separate. AC and DC are a serious issue if on the same track, but if kept isolated from each other then even on parallel tracks they're much less of a problem for each other

A smaller scale version of Reading!

 

[zwk500]

A smaller scale version of Reading!

Reading, Highbury & Islington, and the DC lines from Queens Park to Watford Junction.

 

[Zomboid]

Reading, Highbury & Islington, and the DC lines from Queens Park to Watford Junction.

Allerton/ Hunts Cross, the LTS along the district line...
There's loads of examples where it's not an issue, so shouldn't be impossible at Basingstoke either

 

[MadMac]

Muirhouse South Junction - Larkfield Junction. As matters stand, if there’s a problem around the Muirhouse area, electrics coming from Barrhead/East Kilbride are stuck with no way around it.

Winchburgh - Dalmeny. As above.

Ayr-Girvan is just outwith the criteria at 17 miles.

As Oxenholme-Windermere has been mentioned, wasn’t that supposed to be done as an addon to the Blackpool electrification, the justification being reduction of diesel empty stock moves to/from Manchester?

 

[Mgameing123]

At Basingstoke you'd have the issue of having both OHLE and 3rd rail in the same station. Then the question of whether it's worth converting the third rail network to OHLE arises.

To make use of electric power in as many places as possible, a new XC intercity unit would require pantographs, batteries, third rail shoes as well as a diesel engine as a backup. A highly complex ask for any train manufacturer.

Why can’t OHLE and Third Rail coexist? Are we forgetting about Ashford International or the Thameslink Core?

 

[Zomboid]

Why can’t OHLE and Third Rail coexist? Are we forgetting about Ashford International or the Thameslink Core?

It's possible but very complicated.

One benefit of batteries could be to eliminate the complexities of dual electrification on the same track.

 

[Falcon1200]

Why can’t OHLE and Third Rail coexist? Are we forgetting about Ashford International or the Thameslink Core?

And Euston, surely?!!

 

[fwsmVor]

Only if you opened a station for Heysham itself and extended the Morecambe service onto there. But that's getting a bit off-topic.

Is there any single gap 15 miles or less in length that would allow a service to immediately be replaced by EMUs?

I think the North Downs line's gaps are less than 15 miles in total?

 

[61653 HTAFC]

The Thames Valley Branches could still make sense. It prevents having a microfleet of battery trains.

Marlow will always need a "micro-fleet" of some sort. The current Turbos still based at Reading excepted though it's a smaller fleet than it used to be. Whether you put the wires up on the full length of each branch or use batteries, you still need a few non-standard 2-car units to do the Bourne End reversal.

 

[Mgameing123]

Marlow will always need a "micro-fleet" of some sort. The current Turbos still based at Reading excepted though it's a smaller fleet than it used to be. Whether you put the wires up on the full length of each branch or use batteries, you still need a few non-standard 2-car units to do the Bourne End reversal.

And also one other thing. What’s the point of not electrifying the Greenford Branch when it anyways needs electrification when it becomes Chilterns turn to be electrified?

 

[Paul AC]

As others have said, having dc and ac electrification at the same location is possible (clearly) but best avoided. It causes complications with the earthing and return current wiring. (AC) transformers really don't like even small levels of dc current flowing through them, and one maxim for electrical gear is that unless you absolutely prevent current from passing via a particular route it will find some way of doing so.

Euston is the most difficult location, with the long stretch of duplicate electrification up to Camden Jn. A strange effect occasionally seen here is when the magnetic field from under-track dc power cables due to dc trains accelerating up the hill trigger the APC receiver on an AC train, causing the latter to think it's entered a neutral section.

At Ashford International, the connecting lines between the high speed (25 kV only) and the station area (both electrifications) had special isolations in the running rails but these were found to cause damage to some of the equipment in Class 374 trains passing over the 'gap'. This caused the 3784s to be barred from calling at Ashford for a while. The problem was fixed by adding some extra electrical switchgear.

 

[WAO]

The problem with a microfleet is micro capacity. Having just been to Alton (from Reading) and had the joy of 12 cars off-peak from Ash Vale after the stuffed 3 car ND Turbo to North Camp (cancellations galore), it's high time the BEMU nonsense for busy lines ceased.

WAO

 

[Falcon1200]

As others have said, having dc and ac electrification at the same location is possible (clearly) but best avoided. It causes complications with the earthing and return current wiring. (AC) transformers really don't like even small levels of dc current flowing through them, and one maxim for electrical gear is that unless you absolutely prevent current from passing via a particular route it will find some way of doing so.

Interesting, thanks for the detail. Where overhead and third rail systems meet, for example at Basingstoke should the Reading line ever be wired, would changing over on the move be feasible, to allow a section of dual electrification on the double line approaching Basingstoke? Presumably Eurostars changed over on the move, pre HS1.

 

[Zomboid]

Interesting, thanks for the detail. Where overhead and third rail systems meet, for example at Basingstoke should the Reading line ever be wired, would changing over on the move be feasible, to allow a section of dual electrification on the double line approaching Basingstoke? Presumably Eurostars changed over on the move, pre HS1.

Possible - absolutely. Whether it's the best thing to do would be up to the designers of the system should it be built (and would also be subject to other factors such as whether the AC was going to continue beyond Basingstoke).

What's most likely IMO is that future dual voltage trains will be fitted with smallish batteries so that the systems can be kept separate. Both Basingstoke and Reading are good examples of where that would be useful. Future BEMUs for XC ought to be dual voltage and if P5 at Basingstoke is wired they'd have to drop the pan on the approach and run on battery into the station, then lower the shoes.

 

[Falcon1200]

What's most likely IMO is that future dual voltage trains will be fitted with smallish batteries so that the systems can be kept separate.

That would be a sensible and relatively simple solution.

 

[Zomboid]

That would be a sensible and relatively simple solution.

I would even advocate it for some existing changeovers, such as Thameslink where the equipment to try and control the return current is spectacularly complex. Just chuck it in the bin and use a battery between City TL and Farringdon. At least when it's time to renew those trains!