LUL Substations

[GraphitProjekt]

For quite a while I've been investigating traction substations and power systems on the national network, really just cataloguing what's there since - as opposed to say signalling - it's much more of an under-reported topic.

Anyway, I've found LUL and other TfL systems a lot more opaque compared to the national network and there's not a lot out there to go off. But I did finally come across a couple sources floating around the internet of what DC substations are around. Mainly this site: http://www.trainweb.org/tubeprune/tractioncurr.htm. But it is at least 25 years old and it's a bit unclear whether it's discussing actual sections between substations are sectionalisation areas which I've heard are meant to include several substations in a row.
But nonetheless it's the best source I have so I've compiled it into a map and am hoping others can help me fill in any blanks. Especially if any of these are TPHs or there are other sites that are TPHs

Some things that surprised me:
- Is Oxford Rd really only on the Bakerloo line
- Interesting that the Victoria Line (and to lesser extent JLE) mostly avoided re-using the names/sites of passenger stations
- On that point, I wonder if some of the central London ones are the same substation but with different names for different DC switching rooms (Hays Mews vs Bond Street, Green Park vs Dover Street)
- No s/s at Bank? I heard there was meant to be a TPH here on the W&C but it was never commissioned or something
- Nothing between Elephant & Castle and Old Street on the City branch is surprising
- Kennington was apparently only added for the Battersea Park extension

I'm also quite interested in the extent of the 22kV feeder network. I've found a small amount online which I've added to the map. I wonder if, say, the Central Line or outer reaches of the Met mainly works off 22kV simply because of how far out it reaches.

 

[Central]

Most train depots on LUL have substations.

 

[GraphitProjekt]

Yeah that's been another factor of confusion. As a general rule would they also be responsible for the main running lines? I'm assuming this is the case with Stratford Market. But like Morden? Perhaps not because South Wimbledon would be so close.

 

[Taunton]

Interesting link. I read the part about live rail gaps sufficiently long that the shoes on a car don't bridge into an isolated section, and wonder why the lights don't go out, or at least drop back to the emergency lighting, when passing over these.

 

[GraphitProjekt]

Interesting link. I read the part about live rail gaps sufficiently long that the shoes on a car don't bridge into an isolated section, and wonder why the lights don't go out, or at least drop back to the emergency lighting, when passing over these.

I remember quite a few years ago, like in the late 2000s it was quite common for lights to flicker in and out randomly on tube trains. I can't exactly recall which lines this was on, probably the Piccadilly. My dad explained this to me as acceleration drawing more power away - similar to the car radio dropping out when you start it. But it might make more sense that a substation gap is involved. Curiously this doesn't seem to happen anymore. Maybe there are low voltage wiring between cars? Or capacitors in the circuits or something.

 

[Mojo]

I remember quite a few years ago, like in the late 2000s it was quite common for lights to flicker in and out randomly on tube trains. I can't exactly recall which lines this was on, probably the Piccadilly. My dad explained this to me as acceleration drawing more power away - similar to the car radio dropping out when you start it. But it might make more sense that a substation gap is involved. Curiously this doesn't seem to happen anymore. Maybe there are low voltage wiring between cars? Or capacitors in the circuits or something.

This thread from a couple of years ago may interest you
https://www.railforums.co.uk/thread...-go-on-and-off-when-going-over-points.263915/. In summary this still happens but only on the older trains.

More so than sub gaps people probably only really noticed the lights going off and on when traversing pointwork.

 

[Taunton]

OK, it just seems a feature of modern lighting that it holds over short supply breaks, by various means. I do recall somewhere, it might have been Russia, or maybe New York, where they still had traditional tungsten, over breaks half the lights, alternately on each side, went off and on, then a moment later the other alternate ones did the same, fed apparently from opposite ends of the car, you could then see through the end door the same happening in sequence down the train. The wiring from each car end was zig-zagged to alternate lights on each side.

Back to substations!

 

[Dstock7080]

West Ham (District) has a reasonably new substation, not included in the information above

 

[bramling]

For quite a while I've been investigating traction substations and power systems on the national network, really just cataloguing what's there since - as opposed to say signalling - it's much more of an under-reported topic.

Anyway, I've found LUL and other TfL systems a lot more opaque compared to the national network and there's not a lot out there to go off. But I did finally come across a couple sources floating around the internet of what DC substations are around. Mainly this site: http://www.trainweb.org/tubeprune/tractioncurr.htm. But it is at least 25 years old and it's a bit unclear whether it's discussing actual sections between substations are sectionalisation areas which I've heard are meant to include several substations in a row.
But nonetheless it's the best source I have so I've compiled it into a map and am hoping others can help me fill in any blanks. Especially if any of these are TPHs or there are other sites that are TPHs

Some things that surprised me:
- Is Oxford Rd really only on the Bakerloo line
- Interesting that the Victoria Line (and to lesser extent JLE) mostly avoided re-using the names/sites of passenger stations
- On that point, I wonder if some of the central London ones are the same substation but with different names for different DC switching rooms (Hays Mews vs Bond Street, Green Park vs Dover Street)
- No s/s at Bank? I heard there was meant to be a TPH here on the W&C but it was never commissioned or something
- Nothing between Elephant & Castle and Old Street on the City branch is surprising
- Kennington was apparently only added for the Battersea Park extension

I'm also quite interested in the extent of the 22kV feeder network. I've found a small amount online which I've added to the map. I wonder if, say, the Central Line or outer reaches of the Met mainly works off 22kV simply because of how far out it reaches.


View attachment 204355

There’s a few inaccuracies on the above. Here is a list of LU traction substations

Bakerloo:
Stonebridge Park Depot
Kilburn Park
Baker Street
Oxford Circus
Embankment
Elephant & Castle

Central:
Ruislip Depot
Ruislip
Northolt
Greenford
Brentham
Ealing Broadway TCR
Park Royal
East Acton TCR
Wood Lane
Notting Hill Gate
Bond Street
Holborn
Liverpool Street
Bethnal Green
Bow
Leyton
Leytonstone
South Woodford
Woodford Sidings
Roding Valley
Loughton
Theydon Bois TCR
Epping
Redbridge
Newbury Park
Hainault

Victoria
Walthamstow Central TCR
Forest Road
Northumberland Park Depot
Seven Sisters
Manor House
Drayton Park
Cloudesley Road
Cobourg Street
Dover Street
Gillingham Street
Stockwell
Brixton
(The reason these tend to not be named after stations is because most of these are located at mid-tunnel sites, generally on the location of what was originally a construction site).

Jubilee:
Stanmore
Canons Park
Queensbury
Preston Road
Wembley Park
Neasden Depot
Neasden
Willesden Green
Kilburn (Exeter Road)
Finchley Road
St John’s Wood TPH
Baker Street
Hays Mews
Green Park TPH
Charing Cross
Waterloo
Redcross Way
Canada Water
North Greenwich
Canning Town TPH
Stratford Market Depot

Northern:
Edgware
Burnt Oak
Hendon
Golders Green
Golders Green Depot
Belsize Park
Camden Town
Euston
Leicester Square
Embankment
Lambeth
Nine Elms
Battersea
High Barnet
Totteridge & Whetstone
Woodside Park
Finchley Central
East Finchley
Highgate Sidings
Highgate
Kentish Town
Camden Town
Euston
Angel
Old Street
Elephant & Castle
Stockwell
Clapham Common
Balham
South Wimbledon
Morden

Piccadilly:
Cockfosters
Southgate
Arnos Grove
Wood Green
Manor House
Holloway Road
Russell Square
Holborn
Leicester Square
Hyde Park Corner
South Kensington
Earl’s Court
Barons Court
Ravenscourt Park
Chiswick Park
Acton Town
Northfields
Hounslow
Hounslow West TPH
Hatton Cross
Heathrow Central
Heathrow Terminal 5 TCR
North Ealing
Alperton
Sudbury Hill
Rayners Lane
Eastcote
Ickenham
Uxbridge

District:
North Ealing
Ealing Common Depot
Acton Town
Chiswick Park
Ravenscourt Park
Barons Court
Earl’s Court
Putney Bridge
Cromwell Curve
Notting Hill Gate
Bouverie Place
South Kensington
Victoria
Embankment
Mansion House
Tower Hill
Whitechapel
Campbell Road
West Ham
Plaistow
East Ham
Upney
Heathway
Hornchurch
Upminster
Upminster Depot

Metropolitan:
Chalfont
Chorleywood
Watford TCH
Croxleyhall
Northwood
Uxbridge
Ickenham
Eastcote
Rayners Lane
Harrow
Preston Road
Neasden Depot
Neasden
Willesden Green
Finchley Road
Marlborough Road
Baker Street

H&C
Hammersmith Depot
Shepherd’s Bush
Royal Oak
Bouverie Place
Baker Street
Chalton Street
Farringdon
Moorgate
Whitechapel
Campbell Road
West Ham
Plaistow
East Ham
Upney

Waterloo & City:
Waterloo & City (in Waterloo Depot)

 

[GraphitProjekt]

Thank you for this, very helpful. I'll set about adding them to the map. But considering how many were missing, might be more of a total redraw.

So why are some of them called TCR/TCH while others are TPR/TPH, I presume it's a variation on the same idea. But what could it mean? "Track Classification Room"?

Presumably Stonebridge Park Depot s/s is within LUL property and so makes the cut. I think there are a few Watford DC substations before there (Queens Park, Willesden, Harlesden).

Interesting to know that Cromwell Curve does supply DC, but not Mile End. Are there any other AC only substations out there (other than the six grid supplies)?

 

[bramling]

So why are some of them called TCR/TCH while others are TPR/TPH, I presume it's a variation on the same idea. But what could it mean? "Track Classification Room"?

Think this is just an outcome of being installed at different times so there’s no consistency. TCR is Track Coupling Room, the rest all follow on from that.

Presumably Stonebridge Park Depot s/s is within LUL property and so makes the cut.

Yes, precisely.

Interesting to know that Cromwell Curve does supply DC, but not Mile End. Are there any other AC only substations out there (other than the six grid supplies)?

Theres several switch houses. Cromwell Curve also has one, as is Mile End you mention. Add to that Cobourg Street, Neasden and Mansell Street.

There’s also a significant number of transformer rooms on stations that feed station services (primarily lifts & escalators).

 

[GraphitProjekt]

So now Hays Mews ("Mayfair") on Jubilee Line between Baker Street and Green Park?

And also, is it generally the case that transformer/rectifier sets for DC traction are not powered from 22kV? So, for instance, Cromwell Curve's DC power will be from the 11kV end, it just so happens that the substation steps down 11kV? I've seen mention that Stratford Mkt has a 22kV presence as well.

 

[Nym]

The majority of "Sub Stations" that include Transformer-Rectifiers have their Transformer-Rectifiers connected at 11kV. Very few in my time were 22kV direct Transformer-Rectifiers, even on the VLU (Victoria Line Upgrade) substations.

There's a lot more than the maps there indicate, and for hopefully obvious reasons I won't be listing them.

 

[Sad Sprinter]

There’s a huge substation between Clapham South and Clapham Common. Dominates the local surroundings a bit

 

[bramling]

So now Hays Mews ("Mayfair") on Jubilee Line between Baker Street and Green Park?

Apologies, missed off that one. I’ve amended the earlier post.

 

[GraphitProjekt]

There’s a huge substation between Clapham South and Clapham Common. Dominates the local surroundings a bit

That is Clapham Common substation I believe. Some substations are really quite domineering indeed. Even on new installations like JLE and NLE, I've been surprised by the scale. Southern Region substations also started out quite large but have become progressively smaller over the years to just a few shipping containers these days. But LUL sites have seemingly remained quite large.

== Doublepost prevention - post automatically merged: 22 May 2026 ==

Update to the map, still intriguing to me that there is nothing between Old Street and Elephant & Castle

 

[GraphitProjekt]

I found an interesting article in the Railway Gazette of substation renewal work in the 1950s-60s available on the Internet Archive (as many Railway Gazette issues are). Volume 115, Issue 20, 17th Nov, 1961, p573

The main objective was replacing motor generators with rectifiers and substations to be remotely controlled. The rectifiers were being fitted to allow use with both 33.3Hz and 50Hz supplies for the eventual transition to grid frequency.

But even at that time there was a mix of frequencies going on in that some substations were being renewed and connected into 11kV cables from Greenwich which was already generating at 50Hz as opposed to Neasden and then then Lots Road. These substations being supplied by Greenwich were Elephant & Castle, Whitechapel, Surrey Docks and Moorgate. This did require the use of alternators to then convert from 50hz to 33hz for existing signalling and lighting supplies. (Does LUL signalling still require 33.3Hz?).

Mention was made that at Kilburn Park and Eastcote, rectifiers were salvaged from closed tramways in south London.

The establishment of remote control is interesting as the article mentions that several new power control stations were being set up at this time: Cromwell Curve, Aldgate and Baker Street. As opposed to the centralised Leicester Square that perhaps came later.

There is also this nice graphic of the rebuilding of "Charing Cross" substation which I think is now called Embankment because the Jubilee line built it's own "Charing Cross" s/s

The staging of the work with very rough commencement dates was:
Phase 1 (1953): Bond Street, Whitechapel, Surrey Docks
Phase 2 (1957?): Charing Cross, South Kensington, Earls Court, Moorgate, Eastcote, Kilburn Park
Phase 3 (1959): Croxleyhall, Hyde Park Corner, Acton Town, Baker Street, Belsize Park, Euston, Elephant & Castle, Finchley Road, Hounslow, Kentish Town, Northwood, Willesden Green
Phase 4 (1961?): Bouverie Place, Canons Park, Golders Green, Harrow, Holborn, Ickenham, Lambeth, Liverpool Street, Mansion House, Neasden, Old Street, Putney Bridge, Ravenscourt Park, Russel Square, Stockwell.

It also mentions that out of a total of 87 substations, 45 were within the overall modernisation programme as they were over 40 years of age. So possibly newer branches from the 1930s onwards were always operating with rectifiers and maybe at 50Hz? This could also refer to electrification that was originally built by a grouping railway company like on the Hammersmith branch or on the District east of Whitechapel.

 

[Daniel]

still intriguing to me that there is nothing between Old Street and Elephant & Castle

Intriguing to the line controllers too - always a difficult one when needing to switch power off in an emergency. With such a large section you're almost guaranteed to trap a train mid section.

 

[Mawkie]

Intriguing to the line controllers too - always a difficult one when needing to switch power off in an emergency. With such a large section you're almost guaranteed to trap a train mid section.

I have zero knowledge of the Northern Line, but surely there are some Section Switches?

 

[GraphitProjekt]

Intriguing to the line controllers too - always a difficult one when needing to switch power off in an emergency. With such a large section you're almost guaranteed to trap a train mid section.

It definitely seems like the longest gap in substations for the central area. I'm surprised it can keep up with the power demand since I think the City branch has a slightly more intensive service than the Charing Cross branch (22tph vs 20).

The substation distances in general are a bit strange, they tend to bunch up
Euston – Angel: 1.870
Angel – Old Street: 1.550
Old Street – Elephant & Castle: 3.720
Elephant & Castle – Kennington: 0.850

And otherwise:
Euston – Leicester Square: 2.060
Leicester Square – Embankment: 0.870
Embankment – Lambeth: 1.230
Lambeth – Kennington: 1.030

 

[bramling]

It definitely seems like the longest gap in substations for the central area. I'm surprised it can keep up with the power demand since I think the City branch has a slightly more intensive service than the Charing Cross branch (22tph vs 20).

The substation distances in general are a bit strange, they tend to bunch up
Euston – Angel: 1.870
Angel – Old Street: 1.550
Old Street – Elephant & Castle: 3.720
Elephant & Castle – Kennington: 0.850

And otherwise:
Euston – Leicester Square: 2.060
Leicester Square – Embankment: 0.870
Embankment – Lambeth: 1.230
Lambeth – Kennington: 1.030

Can only assume there isn’t really a need for the section to be broken up. It would have been very easy to utilise the Jubilee Line Extension’s Redcross Way substation, which is physically connected to the Northern Line tunnels just south of London Bridge.

The Bakerloo also has a long section from Kilburn Park to Baker Street.

 

[Daniel]

I have zero knowledge of the Northern Line, but surely there are some Section Switches?

There are a couple - but not massively useful in the situation described - they’re not remotely controlled. LU doesn’t approach stalled trains like Network Rail does - the aim is to have everyone off of a train within an hour.

 

[Nym]

There are a couple - but not massively useful in the situation described - they’re not remotely controlled. LU doesn’t approach stalled trains like Network Rail does - the aim is to have everyone off of a train within an hour.

That is the aim. But given the oversight and decision paralysis that seems to have fallen on all control rooms recently, I've not seen it achieved for a while.

 

[Daniel]

That is the aim. But given the oversight and decision paralysis that seems to have fallen on all control rooms recently, I've not seen it achieved for a while.

Agree to disagree - the vast majority of stalled trains are resolved in less than 60 minutes. You just don’t hear about them unless it all goes wrong!