Aylesbury electrification - how would this happen?

[GraphitProjekt]

(Also, I’ve always thought that third rail is the best idea for the tunnels out of Marylebone, particularly for already dual-voltage Aylesbury services)

yeah if new conductor rail was allowed this would be the best option. Would you have changover for Birmingham trains at Harrow on the Hill but Aylesbury trains remain DC until Amersham. You would probably need to invest in upgrading LUL's substations and their 22kV distribution network.

As a point of interest, new 3rd rail might be a possibility if the conductor rail has new safety features like automatic isolation around station platforms. Network rail's southern region seemed to be hopeful about this in reference to Ucksfield electrification

 

[Richard Scott]

yeah if new conductor rail was allowed this would be the best option. Would you have changover for Birmingham trains at Harrow on the Hill but Aylesbury trains remain DC until Amersham. You would probably need to invest in upgrading LUL's substations and their 22kV distribution network.

As a point of interest, new 3rd rail might be a possibility if the conductor rail has new safety features like automatic isolation around station platforms. Network rail's southern region seemed to be hopeful about this in reference to Ucksfield electrification

Other issue is LU us +420V on 3rd rail and -210V on 4th rail so not quite as simple as just adding a 3rd rail. Would need to make stock so could run on this system as doubt LU will want to change their system?
Maybe should start a new thread as massively drifting here?

 

[Dstock7080]

Other issue is LU us +420V on 3rd rail and -210V on 4th rail so not quite as simple as just adding a 3rd rail. Would need to make stock so could run on this system as doubt LU will want to change their system?

Most of the MET now uses 750V (+500 and -250) except around Neasden/Wembley for Jubilee trains and Rayners Lane-Uxbridge, the later will be increased after the old Piccadilly trains are gone.

 

[GraphitProjekt]

Other issue is LU us +420V on 3rd rail and -210V on 4th rail so not quite as simple as just adding a 3rd rail. Would need to make stock so could run on this system as doubt LU will want to change their system?

I kept my reply above kinda vague because they're a lot of potential solutions to this, none of which are that crazy, but also none of which I'm qualified to decide on.

(At the moment the parts of the LUL line where jubilee and met run side by side are 630V, but the rest of the subsurface lines are 750 or due to be. S7/8 trains are fine with both voltages)

1) use the old compramise voltage of 660V and bond the centre rail to the running rails. (As was previously done on the richmond branch/watford DC)

2) tell the jubillee line to upgrade their trains (like on subsurface/new piccadilly trains) to 750V and bond the centre rail to the running rails (as is currently done on the richmond branch)

3) upgrade the substations (which you'll need to do anyway) to allow 750V on the met and NR tracks, but also 630 on the jubilee ones.

4) the new chiltern rolling stock is fitted for 630V/750V 4th rail + AC overhead.

2 and 3 are probably the most expensive and complicated, 4 is a good idea but NR probably don't want a slightly different weird standard of dual voltage EMU although i think it'd be fine.

Maybe should start a new thread as massively drifting here?

I would be up for a Chiltern electrification thread for sure!

 

[sad1e]

I kept my reply above kinda vague because they're a lot of potential solutions to this, none of which are that crazy, but also none of which I'm qualified to decide on.

(At the moment the parts of the LUL line where jubilee and met run side by side are 630V, but the rest of the subsurface lines are 750 or due to be. S7/8 trains are fine with both voltages)

1) use the old compramise voltage of 660V and bond the centre rail to the running rails. (As was previously done on the richmond branch/watford DC)

2) tell the jubillee line to upgrade their trains (like on subsurface/new piccadilly trains) to 750V and bond the centre rail to the running rails (as is currently done on the richmond branch)

3) upgrade the substations (which you'll need to do anyway) to allow 750V on the met and NR tracks, but also 630 on the jubilee ones.

4) the new chiltern rolling stock is fitted for 630V/750V 4th rail + AC overhead.

2 and 3 are probably the most expensive and complicated, 4 is a good idea but NR probably don't want a slightly different weird standard of dual voltage EMU although i think it'd be fine.

I would be up for a Chiltern electrification thread for sure!

if you were to use bi mode 3rd rail and OHLE stock you wouldn't even have to order completely new stock , just order another batch of 377/7s , maybe something else for the longer distance Birmingham Journeys but if 377's run to Brighton they should be fine for Birmingham.

 

[43096]

if you were to use bi mode 3rd rail and OHLE stock you wouldn't even have to order completely new stock , just order another batch of 377/7s , maybe something else for the longer distance Birmingham Journeys but if 377's run to Brighton they should be fine for Birmingham.

You can't order more 377/7s. They are a design that has been out of production for some time.

 

[GraphitProjekt]

I don't think we should buy anymore electrostars/aventras. They have the wrong platform height by design.

I don't even think you can anyway, they're bombardier platforms and Alstom are (or will do if they win the contract) introducing their own stuff at Derby for the future Southeastern order.

 

[sad1e]

I don't think we should buy anymore electrostars/aventras. They have the wrong platform height by design.

I don't even think you can anyway, they're bombardier platforms and Alstom are (or will do if they win the contract) introducing their own stuff at Derby for the future Southeastern order.

A 377/7 is just an example, i think if new stock is ordered they should order something tried and tested so it doesn't end up like the 810s which are currently taking years to get working properly and to train on.
A shorter 700 wouldn't be that bad as long as they wouldn't have ironing boards.

 

[D365]

A shorter 700 wouldn't be that bad as long as they wouldn't have ironing boards.

Desiro City is also out of production.

I don't think we should buy anymore electrostars/aventras. They have the wrong platform height by design.

I don't even think you can anyway, they're bombardier platforms and Alstom are (or will do if they win the contract) introducing their own stuff at Derby for the future Southeastern order.

Reportedly the new Alstom 'Adessia' platform will include a low floor variant.

 

[I'm here now]

GWR could be a shout. Put them on Exeter-Cardiff Central services (as they'll become when the service to Penzance is split at Exeter) and allow the IETs on them to be used on more and longer intercity services. If there's a surplus then the frequency could be increased (at least between Taunton and Bristol); stations like Bridgwater could do with a higher frequency for the area its serving.

Why are they splitting at Exeter?

 

[TT-ONR-NRN]

Why are they splitting at Exeter?

To allow 175s to remain localised to the area.

 

[I'm here now]

To allow 175s to remain localised to the area.

Fair enough. Thanks.

 

[MatthewHutton]

Most of the MET now uses 750V (+500 and -250) except around Neasden/Wembley for Jubilee trains and Rayners Lane-Uxbridge, the later will be increased after the old Piccadilly trains are gone.

How difficult would it be to change to +750 and -0 and bond the middle track so you could use e.g. a class 769 for the Aylesbury-Marylebone trains? And would that be worthwhile in terms of performance?

And also on Chiltern if you converted more of the London-Birmingham service to locomotive driven could you make the High Wycombe-London stopping services use a class 168 and therefore speed that service up enough to have true half hourly service to Oxford/Birmingham and therefore have true half hourly service from London to High Wycombe?

 

[sad1e]

How difficult would it be to change to +750 and -0 and bond the middle track so you could use e.g. a class 769 for the Aylesbury-Marylebone trains? And would that be worthwhile in terms of performance?

And also on Chiltern if you converted more of the London-Birmingham service to locomotive driven could you make the High Wycombe-London stopping services use a class 168 and therefore speed that service up enough to have true half hourly service to Oxford/Birmingham and therefore have true half hourly service from London to High Wycombe?

Wouldn't a 230 with 3rd rail shoes be better for Aylesbury - Marylebone than a 769. The traction motors in the 230s are from tube stock so it would probably be a lot easier to run them off the met lines power supply.

 

[D365]

The traction motors in the 230s are from tube stock so it would probably be a lot easier to run them off the met lines power supply.

None of the completed 230s retain the Brush ’LT’ motors or the associated traction circuits.

 

[Zomboid]

The S stock should be capable of running on 0-660 rather than the usual 440 - 220, as it runs to Richmond and Wimbledon (I doubt the S8 would differ from the S7), though in that arrangement I doubt a 769 would be the answer, unless they're much faster accelerating now than they were as 319s.
Also LU would have to significantly change how they do their DC electrification to allow that as their running rails are not presently part of the circuit. It's doable, but expensive and wouldn't offer LU any benefits.

 

[GraphitProjekt]

How difficult would it be to change to +750 and -0 and bond the middle track so you could use e.g. a class 769 for the Aylesbury-Marylebone trains? And would that be worthwhile in terms of performance?

And also on Chiltern if you converted more of the London-Birmingham service to locomotive driven could you make the High Wycombe-London stopping services use a class 168 and therefore speed that service up enough to have true half hourly service to Oxford/Birmingham and therefore have true half hourly service from London to High Wycombe?

this arrangement already exists on the Richmond branch so it's for sure technically feasible. The only issue I can see is that the jubilee line currently shares the substations there so all LUL lines there run off the usual +440 -220. The conversion work on the substations to produce extra arrangements of voltages and to re-spec all the signalling are all possible but cause a lot of disruption and expense with no benefit to LUL.
The thing is though, any Chiltern electrification will involve new rolling stock being procured - so would it really be so bad to have a National Rail train with dual voltage AC and 630V 4th rail? It's not like it will ever encounter the 750V 3rd rail area.

 

[Zomboid]

Leasing companies would probably want something that would work on conventional 3rd rail systems.
Though the jubilee line isn't relevant, as the lines join at Harrow on the Hill, so it'd be entirely possible to have a parallel 750V section (with it's own power supply) where the Jubilee runs.

25kV/ Battery would be more likely, using the battery for the Harrow to Amersham bit.

 

[BlueLeanie]

Leasing companies would probably want something that would work on conventional 3rd rail systems.
Though the jubilee line isn't relevant, as the lines join at Harrow on the Hill, so it'd be entirely possible to have a parallel 750V section (with it's own power supply) where the Jubilee runs.

25kV/ Battery would be more likely, using the battery for the Harrow to Amersham bit.

Battery life is now good enough to order a new S8 derivative and have Met services run all the way to Aylesbury.

 

[GraphitProjekt]

Yeah I think we all know any Chiltern electrification project in reality would use a battery/AC solution. It's interesting to speculate on what could be done though. The other question this brings to mind is whether the NwR tracks between Marylebone and Harrow on the Hill would actually receive any electrification system. It's definitely possible to run 25kV adjacent to LUL lines (like on LTS) but I'm sure some kind of expense is incurred for installing stray current mitigation.

The other benefit about having battery trains is that in the long run, you may want to remove the Chesham and Amersham branches from the Met line and run them on the Chiltern system which would mean you could fully separate LUL and NR systems since Moor Park to Harrow would be 2 double track railways adjacent to each other. To carry out a conversion like that in stages it'd be useful to have battery trains.

 

[Zomboid]

It'd be interesting to see what happens between Neasden and Marylebone. Presumably the station itself would need wires for charging, but would the tunnels or section adjacent to the underground? Would the station be enough to get a battery train to Amersham regularly? Assuming the wires pick up there for the run to Aylesbury.

I don't generally like the idea of discontinuous electrification on major routes, but I'm not sure Marylebone is really major enough, if there are wires from Neasden to Oxford/ Bicester and some more at the Birmingham end. And those tunnels are probably not going to be easy to wire.

 

[zwk500]

It'd be interesting to see what happens between Neasden and Marylebone. Presumably the station itself would need wires for charging, but would the tunnels or section adjacent to the underground? Would the station be enough to get a battery train to Amersham regularly? Assuming the wires pick up there for the run to Aylesbury.

I don't generally like the idea of discontinuous electrification on major routes, but I'm not sure Marylebone is really major enough, if there are wires from Neasden to Oxford/ Bicester and some more at the Birmingham end. And those tunnels are probably not going to be easy to wire.

Marylebone-Oxford/Birmingham should be wired throughout, but tbh Aylesbury could probably cope with the Greenford style fast-dump charging ports rather than needing to fuss about with OLE everywhere, at least until EWR is wired.

Battery units can quite happily cope with 50 mile ranges today, some up to 80. Harrow-on-the-Hill South Jn to Amersham is about 14.5 miles, Harrow to Great Missenden 20 miles, and Harrow to AVP 30.5 miles. With top-up from wires Harrow-Marylebone (7 miles) and then a fast-dump at Aylesbury/AVP the value of OLE on that section seems fairly limited.
If East-West rail was fully wired, and fed from the HS2 feeder, then I could see the value of extending electrification from Verney Jn to Amersham as part of making the MK-Aylesbury service fully EMU.

 

[MatthewHutton]

this arrangement already exists on the Richmond branch so it's for sure technically feasible. The only issue I can see is that the jubilee line currently shares the substations there so all LUL lines there run off the usual +440 -220. The conversion work on the substations to produce extra arrangements of voltages and to re-spec all the signalling are all possible but cause a lot of disruption and expense with no benefit to LUL.
The thing is though, any Chiltern electrification will involve new rolling stock being procured - so would it really be so bad to have a National Rail train with dual voltage AC and 630V 4th rail? It's not like it will ever encounter the 750V 3rd rail area.

Not just Richmond. Bakerloo north of Queens Park too.

And the Met line is already 750V north of the junctions just north of Harrow on the Hill.

== Doublepost prevention - post automatically merged: 13 Apr 2025 ==

Marylebone-Oxford/Birmingham should be wired throughout, but tbh Aylesbury could probably cope with the Greenford style fast-dump charging ports rather than needing to fuss about with OLE everywhere, at least until EWR is wired.

Battery units can quite happily cope with 50 mile ranges today, some up to 80. Harrow-on-the-Hill South Jn to Amersham is about 14.5 miles, Harrow to Great Missenden 20 miles, and Harrow to AVP 30.5 miles. With top-up from wires Harrow-Marylebone (7 miles) and then a fast-dump at Aylesbury/AVP the value of OLE on that section seems fairly limited.
If East-West rail was fully wired, and fed from the HS2 feeder, then I could see the value of extending electrification from Verney Jn to Amersham as part of making the MK-Aylesbury service fully EMU.

If you are doing Marylebone to Oxford/Birmingham you have to do Aylesbury for the depot access. Is it not worth doing Amersham-Aylesbury and Harrow on the Hill to Wembley at the same time?

 

[BlueLeanie]

Yeah I think we all know any Chiltern electrification project in reality would use a battery/AC solution. It's interesting to speculate on what could be done though. The other question this brings to mind is whether the NwR tracks between Marylebone and Harrow on the Hill would actually receive any electrification system. It's definitely possible to run 25kV adjacent to LUL lines (like on LTS) but I'm sure some kind of expense is incurred for installing stray current mitigation.

The other benefit about having battery trains is that in the long run, you may want to remove the Chesham and Amersham branches from the Met line and run them on the Chiltern system which would mean you could fully separate LUL and NR systems since Moor Park to Harrow would be 2 double track railways adjacent to each other. To carry out a conversion like that in stages it'd be useful to have battery trains.

This is going way off-topic but...

Given that TfL goes as far as Reading, I don't see why TfL shouldn't extend the Met to Aylesbury with four services an hour using battery hybrid stock, ending Chiltern services to Aylesbury via Harrow.

This would then ideally release some Chiltern DMUs to operate additional semi-fasts to AVP via High Wycombe.

And eventually get the knitting up to Oxford, Banbury and AVP/Calvert, to allow Class 93 hauled Mk5s. (93s to allow the services to extend out to the BMW line).

 

[Zomboid]

If you are doing Marylebone to Oxford/Birmingham you have to do Aylesbury for the depot access

If you're electrifying the Chiltern line then the turbo depot is pretty irrelevant. The hypothetical new electric trains will almost certainly get their own new depot somewhere along the way.

 

[zwk500]

If you are doing Marylebone to Oxford/Birmingham you have to do Aylesbury for the depot access. Is it not worth doing Amersham-Aylesbury and Harrow on the Hill to Wembley at the same time?

Between Wembley LMD, Oxford, Banbury and Tyseley, would you still need to have EMU access to Aylesbury?

 

[JonathanH]

Given that TfL goes as far as Reading, I don't see why TfL shouldn't extend the Met to Aylesbury with four services an hour using battery hybrid stock, ending Chiltern services to Aylesbury via Harrow.

The concern with that is that Chiltern currently provides additional capacity on the Amersham to London corridor. Can all those passengers be accommodated on the Metropolitan Line south of Harrow-on-the-Hill, once the Uxbridge trains are taken into account?

 

[sad1e]

This is going way off-topic but...

Given that TfL goes as far as Reading, I don't see why TfL shouldn't extend the Met to Aylesbury with four services an hour using battery hybrid stock, ending Chiltern services to Aylesbury via Harrow.

This would then ideally release some Chiltern DMUs to operate additional semi-fasts to AVP via High Wycombe.

And eventually get the knitting up to Oxford, Banbury and AVP/Calvert, to allow Class 93 hauled Mk5s. (93s to allow the services to extend out to the BMW line).

The Elizabeth line only goes as far as Reading for operational convenience. If TFL had their way , the GWR Didcot stopper didn't exist , and there was space at Maidenhead for terminating plats the Elizabeth line would Terminate at Maidenhead.

 

[MatthewHutton]

Between Wembley LMD, Oxford, Banbury and Tyseley, would you still need to have EMU access to Aylesbury?

Chiltern sends Oxford trains to Aylesbury regularly. You can see it in the timetable.

== Doublepost prevention - post automatically merged: 13 Apr 2025 ==

If you're electrifying the Chiltern line then the turbo depot is pretty irrelevant. The hypothetical new electric trains will almost certainly get their own new depot somewhere along the way.

Doesn’t giving them a new depot add costs?

 

[zwk500]

Chiltern sends Oxford trains to Aylesbury regularly. You can see it in the timetable.

But does it have to? Given any depot will be being rebuilt for EMUs, why would it not be possible to reconfigure Banbury or Wembley to do what Aylesbury does today?

Doesn’t giving them a new depot add costs?

It does, but the new trains will probably need the existing depots rebuilt if not provided with a new depot, and a new depot can allow for more efficient operations.