Possibility of untangling the LU subsurface lines?

[miklcct]

The subsurface Underground lines have a very complex running patterns shared on the same tracks for a city metro which is bad for reliability.

There are many conflicting moves on level junctions around the circle, and some of the circle only runs every 10 minutes.

I'm thinking how it's possible to untangle all the lines to improve reliability while keeping the current frequency, which means running the full circle every 5 minutes and the northern part every 2.5 minutes, with the ability to fine tune them without affecting other lines.

What I can think of now is
- Get rid of the Metropolitan from the circle by terminating them all at Baker Street
- Get rid of the District from the circle by terminating them all at High Street Kensington
- Run the circle and Hammersmith every 5 instead of 10 minutes, giving a headway of every 2.5 minutes in the northern part and every 5 minutes in the southern part.
- Half of the Hammersmith trains will terminate at Barking, with trains running to Upminster every 10 minutes

However, to make this work, we will still need to remove the conflicting moves at Pread Street Junction and Aldgate Junction. Specifically, we will need a way to separate the Circle and Hammersmith platforms at Edgware Road, and add a line to allow westbound Hammersmith trains to avoid the clockwise circle. Preferably Aldgate platforms are added to the Hammersmith line to change to southern circle as well as part of the improvement.

Are these two pieces of infrastructure improvement possible?

 

[yorkie]

- Get rid of the Metropolitan from the circle by terminating them all at Baker Street

Is there sufficient capacity for this? Both in terms of platform capacity for trains and also for the station to be able to accommodate huge numbers of passengers transferring between trains?

When you have several train loads, each with several hundred people on board, all wanting to transfer to onward services, would this not cause problems?

- Get rid of the District from the circle by terminating them all at High Street Kensington

Would there be sufficient capacity available to enable this? Or do you propose building new platforms?

 

[stuu]

The subsurface Underground lines have a very complex running patterns shared on the same tracks for a city metro which is bad for reliability.

There are many conflicting moves on level junctions around the circle, and some of the circle only runs every 10 minutes.

I'm thinking how it's possible to untangle all the lines to improve reliability while keeping the current frequency, which means running the full circle every 5 minutes and the northern part every 2.5 minutes, with the ability to fine tune them without affecting other lines.

What I can think of now is
- Get rid of the Metropolitan from the circle by terminating them all at Baker Street
- Get rid of the District from the circle by terminating them all at High Street Kensington
- Run the circle and Hammersmith every 5 instead of 10 minutes, giving a headway of every 2.5 minutes in the northern part and every 5 minutes in the southern part.
- Half of the Hammersmith trains will terminate at Barking, with trains running to Upminster every 10 minutes

However, to make this work, we will still need to remove the conflicting moves at Pread Street Junction and Aldgate Junction. Specifically, we will need a way to separate the Circle and Hammersmith platforms at Edgware Road, and add a line to allow westbound Hammersmith trains to avoid the clockwise circle. Preferably Aldgate platforms are added to the Hammersmith line to change to southern circle as well as part of the improvement.

Are these two pieces of infrastructure improvement possible?

66 million journeys are made on the Metropolitan line each year, a great many of them are into the city. Removing through trains would be wildly unpopular

The current set up works well, the busiest sections have higher frequencies. The SSL east of Baker St has a peak frequency of 32 tph. You are proposing to cut that to 24tph, which is very much not keeping the current frequency... whilst at the same time making tens of thousands of people change trains at Baker St. Not going to work

 

[zwk500]

The London Underground's been running for 150 years, it's got pretty good at spotting passenger trends through London. This looks a lot like map-tidying than actually trying to offer a better service

However, to make this work, we will still need to remove the conflicting moves at Pread Street Junction and Aldgate Junction. Specifically, we will need a way to separate the Circle and Hammersmith platforms at Edgware Road, and add a line to allow westbound Hammersmith trains to avoid the clockwise circle. Preferably Aldgate platforms are added to the Hammersmith line to change to southern circle as well as part of the improvement.

Are these two pieces of infrastructure improvement possible?

Possible: yes, in theory. But there's so much underground development in those locations that it may not be physically possible and if it is, the lines are only just below the surface so the cost of tunnelling anything will be astronomic.

 

[Magdalia]

- Get rid of the Metropolitan from the circle by terminating them all at Baker Street
- Get rid of the District from the circle by terminating them all at High Street Kensington
- Run the circle and Hammersmith every 5 instead of 10 minutes, giving a headway of every 2.5 minutes in the northern part and every 5 minutes in the southern part.
- Half of the Hammersmith trains will terminate at Barking, with trains running to Upminster every 10 minutes

You assert that this maintains current frequencies, but actually it is savage cutbacks. The Baker Street-Liverpool Street section has already been mentioned, but the Tower Hill-Gloucester Road section is even worse, reducing from a train every 2 minutes to a train every 5 minutes, and with no through trains from either end of the District Line to key destinations such as Victoria, Westminster and Embankment.

This reminds me a bit of what the subsurface lines were like 40 years ago:

• Circle Line every 8 minutes
• Hammersmith and City every 8 minutes terminating Whitechapel except running through to Plaistow or Barking in the peaks
• Metropolitan all terminating Baker Street except in the peaks
• District Edgware Road-Wimbledon every 8 minutes
• District Richmond and Ealing Broadway every 8 minutes I can't remember which of these went to Upminster and which terminated at Tower Hill outside the peaks

One factor you don't take into account is station facilities: most are very cramped with narrow platforms and walkways. Some have no escalators or lifts, like Baker Street or the westbound platform at Liverpool Street. Large numbers of people changing trains is a significant consideration: have you ever been at Earls Court in the evening peak?

However, to make this work, we will still need to remove the conflicting moves at Pread Street Junction and Aldgate Junction. Specifically, we will need a way to separate the Circle and Hammersmith platforms at Edgware Road, and add a line to allow westbound Hammersmith trains to avoid the clockwise circle. Preferably Aldgate platforms are added to the Hammersmith line to change to southern circle as well as part of the improvement.

Are these two pieces of infrastructure improvement possible?

Grade separation on the subsurface lines is, in practical terms, impossible. These lines were built by cut and cover, not tunnelling. To change the layout you need to:

• demolish lots of buildings
• sever gas, water and sewage pipes plus electricity and telecommunications cables
• dig a big hole
• lay your new tracks, including tunnelling to get the grade separation
• put it all back together again

That's why we got the Elizabeth Line instead, and look what happened there.

I think there's a case for reviewing the current subsurface timetables, but not yet. A new timetable needs to be informed by:

• impact of Elizabeth Line on travel patterns
• impact of Working From Home, especially in the City and Whitehall
• impact of changes in tourism

Nobody knows the answers on any of those yet.

 

[Wolfie]

The subsurface Underground lines have a very complex running patterns shared on the same tracks for a city metro which is bad for reliability.

There are many conflicting moves on level junctions around the circle, and some of the circle only runs every 10 minutes.

I'm thinking how it's possible to untangle all the lines to improve reliability while keeping the current frequency, which means running the full circle every 5 minutes and the northern part every 2.5 minutes, with the ability to fine tune them without affecting other lines.

What I can think of now is
- Get rid of the Metropolitan from the circle by terminating them all at Baker Street
- Get rid of the District from the circle by terminating them all at High Street Kensington
- Run the circle and Hammersmith every 5 instead of 10 minutes, giving a headway of every 2.5 minutes in the northern part and every 5 minutes in the southern part.
- Half of the Hammersmith trains will terminate at Barking, with trains running to Upminster every 10 minutes

However, to make this work, we will still need to remove the conflicting moves at Pread Street Junction and Aldgate Junction. Specifically, we will need a way to separate the Circle and Hammersmith platforms at Edgware Road, and add a line to allow westbound Hammersmith trains to avoid the clockwise circle. Preferably Aldgate platforms are added to the Hammersmith line to change to southern circle as well as part of the improvement.

Are these two pieces of infrastructure improvement possible?

You have a fundamental misconception of how the sub-surface lines on the Underground work. The reality is that the Hammersmith and City and District lines are the key lines and the Circle line is overlaid on them.

Your proposal would be as popular as a hole in the head with the travelling public and would lead to utter carnage at the stations which you propose lines are terminated and people have to change.

This looks like yet more proposed change for the sake of it.

Edited to add: For clarity perhaps "in central London" should be added to the first sentence.

 

[miklcct]

Would there be sufficient capacity available to enable this? Or do you propose building new platforms?

The SSL east of Baker St has a peak frequency of 32 tph. You are proposing to cut that to 24tph, which is very much not keeping the current frequency...

The Baker Street-Liverpool Street section has already been mentioned, but the Tower Hill-Gloucester Road section is even worse, reducing from a train every 2 minutes to a train every 5 minutes, and with no through trains from either end of the District Line to key destinations such as Victoria, Westminster and Embankment.

Sorry I have miscalculated the District Line frequency above. The above is all based on off-peak frequency.

Instead, my proposal should be:
* Hammersmith line running every 5 minutes for the whole way.
* Circle line running every 5 minutes for the whole circle, and short working between Tower Hill and Edgware Road every 5 minutes.

Of course if we can grade-separate the Gloucester Road junction we can separate the district line into two, one running into the circle, another terminating at High Street Kensington without conflicting moves.

The main point here is to get rid of all conflicting moves which limit scheduling and train addition. Without any conflicting moves we can easily change a 24 tph timetable to a 34 tph timetable as long as the signalling system supports close running.

 

[Magdalia]

You have a fundamental misconception of how the sub-surface lines on the Underground work. The reality is that the Hammersmith and City and District lines are the key lines and the Circle line is overlaid on them.

I agree with this. Having lived most of my life outside London, but worked there for most of my career, I'd say it was a misconception that I arrived with but quickly discarded.

If I was a Londoner, I'd just junk the Circle Line entirely. I know that I quickly devised workarounds so that I didn't have to use it and I expect that a lot of Londoners do the same. I see the Circle Line as a sort of quarantine for country people travelling between the London Main Line stations, passing through without having to know anything about what's in between.

 

[Bletchleyite]

I agree with this. Having lived most of my life outside London, but worked there for most of my career, I'd say it was a misconception that I arrived with but quickly discarded.

If I was a Londoner, I'd just junk the Circle Line entirely. I know that I quickly devised workarounds so that I didn't have to use it and I expect that a lot of Londoners do the same. I see the Circle Line as a sort of quarantine for country people travelling between the London Main Line stations, passing through without having to know anything about what's in between.

I used to think that, but now it's not a continuous circle it's pretty reliable.

I think if I was going to do anything I'd rename the Circle "Circle and Hammersmith", double its frequency and extend some or all Met services to Upminster instead of the H&C service.

 

[Magdalia]

I think if I was going to do anything I'd rename the Circle "Circle and Hammersmith", double its frequency and extend some or all Met services to Upminster instead of the H&C service.

But you would have to take out paths for District Line trains between Aldgate and Gloucester Road in order to accommodate the doubled frequency on the Circle Line. And you would not have enough platform capacity at Edgware Road, unless you cut the District out of there too. Now you have a fistful of District Line trains coming in from Ealing, Richmond and Wimbledon with nowhere to go.

 

[MarkyT]

...I think there's a case for reviewing the current subsurface timetables, but not yet. A new timetable needs to be informed by:

• impact of Elizabeth Line on travel patterns
• impact of Working From Home, especially in the City and Whitehall
• impact of changes in tourism

Nobody knows the answers on any of those yet.

The north part of the circle will remain the best way to get from Paddington and beyond to the Euston Road area and it's main line termini. Might be worth extending Wimbleware Districts beyond Edgware Road, but not at expense of any Met services whose demand shouldn't be affected by the Lizzy at least. Untangling Praed St - Edgware Road, might be worth looking at, widening the existing c&c tunnel by a track or two on the same level over a relatively short distance.

 

[stuu]

The north part of the circle will remain the best way to get from Paddington and beyond to the Euston Road area and it's main line termini. Might be worth extending Wimbleware Districts beyond Edgware Road, but not at expense of any Met services whose demand shouldn't be affected by the Lizzy at least. Untangling Praed St - Edgware Road, might be worth looking at, widening the existing c&c tunnel by a track or two on the same level over a relatively short distance.

The junction is here. I strongly suspect you would need to demolish everything on one side of road (and possibly both) for ~300m to do that. I wonder what the BCR would be?

 

[MarkyT]

The junction is here. I strongly suspect you would need to demolish everything on one side of road (and possibly both) for ~300m to do that. I wonder what the BCR would be?

Not good at all with that extent of work! The street's quite wide for most of the length though, nearly 20m including pavements, so it might be plausible to add a third track for simultaneous run-ins from the west at least. Close most of the width of the north side pedestrian pavement and one lane of traffic for the duration of works and add a new trench immediately adjacent to the existing tunnel, roofing it over and restoring the street and pavement surface. Near Edgware Rd station, under the Hilton hotel and Marks & Spencers store might be more of a problem...

Something like this perhaps:

 

[stuu]

Not good at all with that extent of work! The street's quite wide for most of the length though, nearly 20m including pavements, so it might be plausible to add a third track for simultaneous run-ins from the west at least. Close most of the width of the north side pedestrian pavement and one lane of traffic for the duration of works and add a new trench immediately adjacent to the existing tunnel, roofing it over and restoring the street and pavement surface. Near Edgware Rd station, under the Hilton hotel and Marks & Spencers store might be more of a problem...

Something like this perhaps:
View attachment 117313

I can see that would be plausible from a rail operations point of view, but I would seriously doubt whether it is possible to build without demolition. Working next to a 160 year old tunnel in the middle of a major city is going to be a little risky, to put it mildly

 

[cle]

One thing I did once read was some work at Paddington (Hammersmith platforms) to add a middle road and a third road - from the old Greenford platform, the room is there in the tunnel - and enable a platform for short runs from Hammersmith. Edgware Road would be ideal, but not likely possible while keeping the stabling roads.

That would at least allow another 6tph Hammersmith shuttles or so, if ever needed - or if through trains needed to be cut a little to allow more Met ones or to relieve Edgware Road. With Crossrail now, Paddington will be a far more useful hub (it already was) - e.g. if headed to Farringdon or the City. Plus West End. Bit of a hike over the bridge.

 

[MarkyT]

One thing I did once read was some work at Paddington (Hammersmith platforms) to add a middle road and a third road - from the old Greenford platform, the room is there in the tunnel - and enable a platform for short runs from Hammersmith. Edgware Road would be ideal, but not likely possible while keeping the stabling roads.

That would at least allow another 6tph Hammersmith shuttles or so, if ever needed - or if through trains needed to be cut a little to allow more Met ones or to relieve Edgware Road. With Crossrail now, Paddington will be a far more useful hub (it already was) - e.g. if headed to Farringdon or the City. Plus West End. Bit of a hike over the bridge.

Two of those short platforms were connected for through running in the distant past. It'd be a good idea to split up waiting passengers by direction on different platforms as the single island and its access routes can get very crowded.

 

[Bald Rick]

I can see that would be plausible from a rail operations point of view, but I would seriously doubt whether it is possible to build without demolition. Working next to a 160 year old tunnel in the middle of a major city is going to be a little risky, to put it mildly

that is putting it mildly! There is absolutely no way that it would be possible to put an extra track down there without demolishing everything on at least one side of the road.


the premise for this thread is hilarious.

 

[MarkyT]

that is putting it mildly! There is absolutely no way that it would be possible to put an extra track down there without demolishing everything on at least one side of the road.

I wonder if the road was closed completely for construction, perhaps the entire old structure might be opened up and removed with new trench walls built outside it. Not saying it wouldn't be horrendously expensive and disruptive. I doubt very much it would be worth it, and the current arrangement seems to work reasonably well.

 

[Bald Rick]

I wonder if the road was closed completely for construction, perhaps the entire old structure might be opened up and removed with new trench walls built outside it. Not saying it wouldn't be horrendously expensive and disruptive. I doubt very much it would be worth it, and the current arrangement seems to work reasonably well.

it still would mean demolishing the buildings.

 

[stuu]

I wonder if the road was closed completely for construction, perhaps the entire old structure might be opened up and removed with new trench walls built outside it. Not saying it wouldn't be horrendously expensive and disruptive. I doubt very much it would be worth it, and the current arrangement seems to work reasonably well.

Ignoring the physical practicalities, if you can close a piece of infrastructure for ~3 years, then it probably doesn't need upgrading in the first place

 

[Basil Jet]

One way to deal with Praed Street junction would be to build new tube gauge tunnels between Royal Oak and Paddington Bakerloo Line station, and reconstruct the Hammersmith branch platforms to be part of the Bakerloo Line, with the current Queens Park terminators sent down there. Paddington (Bishops Road) station would be disused, although Circle & Hammersmith ECS would still go through there. The Paddington Bakerloo platforms are 9 metres lower than Royal Oak platforms, with about 900 metres to make the climb, but I have no idea if Crossrail tunnels might be in the way to make the climb unachievable.

Then you recast the Circle, H&C, Wimbledon - Edgware Road and Wimbledon - Tower Hill / Barking services as follows:

Wimbledon - Edgware Road - Liverpool Street - Victoria - Wimbledon (every 8 minutes clockwise and every 8 minutes anticlockwise)
Barking - Liverpool Street - Edgware Road - Victoria - Tower Hill, with half continuing to Barking (every 8 minutes clockwise and every 8 minutes anticlockwise).

There is no reason why all of these services could not be coloured yellow on the map and called "The Circle Line".

 

[BayPaul]

Why does the circle line need to be kept? Realistically the only useful journeys it provides are Liverpool Street to the southern part of the circle, and between the Western and Southern side, both of which are simple changes.

If you really wanted to untangle (and I'd also argue its uneccesary and a backwards step), why not get rid of circle journeys, and use the extra capacity to allow more services on the other routes.

My personal (utterly impossible to build!) SSL upgrade plan would be to build a new express tunnel from Baker St to Farringdon, and then extensions from Moorgate into East London, and from Aldgate or Aldgate East into South London, allowing the SSL to be separated into 3 pretty much independent lines as follows:
District: Upminster - Ealing B/Richmond /Wimbledon via Victoria
Metropolitan: Uxbridge / Amersham / Chesham / Watford - East London via the new Baker St - Farringdon tunnel
New Name Line: Hammersmith / Wimbledon - South London via King's Cross

As I said, totally impractical to build, but it would massively increase capacity, especially in South and East London, which are both under served.

 

[Magdalia]

My personal (utterly impossible to build!) SSL upgrade plan would be to build a new express tunnel from Baker St to Farringdon, and then extensions from Moorgate into East London, and from Aldgate or Aldgate East into South London

Replace Baker Street with Paddington, Aldgate with Whitechapel and that has already been done. Its called the Elizabeth Line.

 

[BayPaul]

Replace Baker Street with Paddington, Aldgate with Whitechapel and that has already been done. Its called the Elizabeth Line.

I know. And one day it will be full, and more capacity needed. At Baker Street various branches combine into one 'main line', which is the capacity pinch point. If it were possible to remove that pinch point, it would effectively double capacity on the branches, but I am not claiming it would be practical!

 

[mr_jrt]

My own variation of the impractical SSL changes stems from my opinion the DLR's Bank extension was a mistake. I would have diverted the District up at Tower Hill to use the L&B viaduct, then extending that to Custom House. Then branching with one route essentially being the Crossrail route, and the other running up to Beckton and thence across to Dagenham Dock and along to Grays. The Met then replacing the District on the Upminster line.

...and that's just the east side.

On a more serious note, would knocking through platform 4 at Baker St. and having platform 3 as the bay not improve things by removing almost all conflicts? If platform 1 was only used in the peak it could remove all of them in offpeak, I would imagine.

 

[Magdalia]

On a more serious note, would knocking through platform 4 at Baker St. and having platform 3 as the bay not improve things by removing almost all conflicts? If platform 1 was only used in the peak it could remove all of them in offpeak, I would imagine.

One of the oddities of the sub surface lines is that Baker Street does not have the terminating platforms in the middle, and the through lines on the outside, like Edgware Road, Aldgate or Tower Hill. Is there a reason for this?

 

[stuu]

One of the oddities of the sub surface lines is that Baker Street does not have the terminating platforms in the middle, and the through lines on the outside, like Edgware Road, Aldgate or Tower Hill. Is there a reason for this?

History/Geography. The bays weren't built until much later. By the time they were added I would guess it was too difficult/expensive to build them in the centre of the alignment. The tracks are both curving and sloping - the western bay is notably higher at the buffers than the Circle Line platforms

 

[mr_jrt]

I can't say I'd noticed the height being different, but that's probably just me being oblivious. Presumably given the through lines exist the bay's trackbed could be regraded to meet the circle's level, though. I suspect if there is a height aspect the bays would have been deliberately raised up to aid inward braking and outward acceleration.

I recall reading somewhere years ago that full grade separation was once planned/considered, but platform 1 was going to naturally have to be tunnelled, so heaven knows how far back the junction for that road would have to have been.

 

[HamworthyGoods]

I’ve seen all the discussion here but I’m not quite sure what problem is actually trying to be solved here?

 

[stuu]

I can't say I'd noticed the height being different, but that's probably just me being oblivious. Presumably given the through lines exist the bay's trackbed could be regraded to meet the circle's level, though. I suspect if there is a height aspect the bays would have been deliberately raised up to aid inward braking and outward acceleration.

I recall reading somewhere years ago that full grade separation was once planned/considered, but platform 1 was going to naturally have to be tunnelled, so heaven knows how far back the junction for that road would have to have been.

The through Met platforms are on quite a gradient, the western bay is broadly flat, it's probably 1m or so higher than the Circle line. Grade separating would have been interesting - there was a pre-war proposal to build tunnels to Edgware Road though, which became the Bakerloo line to Stanmore instead