Northern City Line southern extension

[VT 390]

If cost was not an issue would it be possible to extend the Northern City Line south from Moorgate to London Bridge via Bank or possibly further south. As this line is above the Northern line would new tunnels need to be dug beside the northern line?
The reason why this extension would be good is that it would help relieve overcrowding on the Northern lines bank Branch between Old Street and London Bridge as well as taking passengers from the Northern City line further in to the city of London.
If Crossrail 2 were to take over the Hertford North and Welywn Garden City local services then could the line from Alexandra Palace to Moorgate and this extension be converted to London Underground operation with a more frequent service operating.

 

[SteveOfTheStow]

The biggest problem under the City is space. There are many underground vaults and railways have to thread between them. As the Northern City is above the Northern line, it doesn't have a lot of space to work with. At Bank you've got many lines intersecting so you'd have to cross those, and then once you hit the Thames you need to be deep enough to go under the river. It'd be easier to abandon the alignment via Moorgate and go to the east nearer Aldgate if you wanted to go further south, I think.

 

[4-SUB 4732]

The biggest problem under the City is space. There are many underground vaults and railways have to thread between them. As the Northern City is above the Northern line, it doesn't have a lot of space to work with. At Bank you've got many lines intersecting so you'd have to cross those, and then once you hit the Thames you need to be deep enough to go under the river. It'd be easier to abandon the alignment via Moorgate and go to the east nearer Aldgate if you wanted to go further south, I think.

Indeed.

We were talking about the DLR extension etc. Old Street - Liverpool Street - Tower Hill - Shadwell is plausible. The DLR not going to Bank wouldn't be a major issue as Tower Hill, Liverpool Street and Old Street are all in the City; and of course the interchanges are available at other places. Central line (Liverpool St), Northern line (Old St), Circle & District (Tower Hill) and there would be a new connection for Crossrail.

If the DLR went up to Finsbury Park (subterranean), you would have the option of using Welwyn and Hertford onto Crossrail 2 via new infrastructure south of Finsbury.

 

[Clip]

Bank/Monument is pretty much full of nowhere to go I would say as this great picture illustrates

 

[Bald Rick]

The biggest problem is that a few metres beyond the end of the tunnels at Moorgate is the Crossrail station and passageways, which go just above the Northern line at right angles to it. Another few hundred metres in and you run into the vaults of the Bank of England, amongst many things.

Because the Northern line is below the NCL, it would mean boring new tunnels from well north of Old Street, splaying out, around and under the Northen, going very deep beneath it. And at that point you may as well build a whole new line.

 

[adamedwards]

The other key issue is the NCL is a 6 car railway in a 12 car world.

 

[Fred26]

Would it be possible to run a new line from Old Street into Liverpool Street, connecting with Crossrail?
If so I can envisage a route to Chingford, and down to Gray's via Barking. As far as the second goes, it would stop at Liverpool Street, Whitechapel, Stratford, Maryland, Forest Gate, Woodgrange Park, Barking, Dagenham Dock, Rainham, Purfleet, Grays. Obviously work in addition to a new tunnel would be needed - flyover/diveunder at Liverpool Street, a flyover between Forest Gate and Woodgrange Park, and a flyover at Barking (which must be happening anyway as part of the GOBLIN extension).

 

[VT 390]

Would it be possible to run a new line from Old Street into Liverpool Street, connecting with Crossrail?
If so I can envisage a route to Chingford, and down to Gray's via Barking. As far as the second goes, it would stop at Liverpool Street, Whitechapel, Stratford, Maryland, Forest Gate, Woodgrange Park, Barking, Dagenham Dock, Rainham, Purfleet, Grays. Obviously work in addition to a new tunnel would be needed - flyover/diveunder at Liverpool Street, a flyover between Forest Gate and Woodgrange Park, and a flyover at Barking (which must be happening anyway as part of the GOBLIN extension).

The northern city will already interchange with Crossrail at Moorgate and at barking it the goblin will use exsistin flyovers used by c2c service to Liverpool Street.

 

[si404]

I suggest that, 6-car and stuff-in-the-way issues, the best extension would be a diversion south of Old Street, and a line functioning at least somewhat as Northern Line relief into the City from South London.

Option 1: Old Street - Barbican - St Pauls - Mansion House - Bankside?/Borough? - Elephant & Castle - Camberwell - Loughborough Junction - Brixton (possible extension south)

Option 2: Old Street - Liverpool Street - Aldgate - Tower (Hill/Gateway / Fenchurch St) - London Bridge - Borough? - Elephant / Bricklayers Arms - Camberwell - Loughborough Junction - Brixton (possible extension south)

Either route would be served by a as-high-a-frequency-as-possible between Bounds Green (where there's a terminating siding) and the southern terminus.

 

[camjkerman]

This is an interesting idea to ponder on if I do say so myself. With the NCL, I wouldn't want to have its extension be popping out anywhere near Blackfriars, London Bridge, Elephant and Castle or Loughborough Junction, it should, ideally pop out going the other way, to not directly compete with the Thameslink Core and its 8 and 12 car trains. So, what I envisage (feel free to pick it to death) is swinging a sharpish turn to head West from Moorgate, with stations at St Pauls, Holborn, Leicester Square and South Kensington, where it joins the District Line and continues along it until just before Richmond, before swinging on to the Hounslow Loop, terminating at Hounslow.

 

[VT 390]

Either route would be served by a as-high-a-frequency-as-possible between Bounds Green (where there's a terminating siding) and the southern terminus.

Do you mean Bowes Park?

Also could all Northern City trains run on the Bowes Park/Hertford North giving a more frequent service and the Welwyn branch b served by Cross Rail 2 by an extension from New Southgate?

 

[si404]

Do you mean Bowes Park?

I do, I always get which one is the Piccadilly and which one is the Hertford loop muddled.

Also could all Northern City trains run on the Bowes Park/Hertford North giving a more frequent service and the Welwyn branch b served by Cross Rail 2 by an extension from New Southgate?

It's theoretically possible, but New Southgate will be difficult to tie in, you're adding issues to CR2, and you're removing the Welwyn branch's easy access to The City, etc by likely not interchanging with the GN&C (Wood Green seemed to be the preferred option over Ally Pally and Turnpike Road).

I'd certainly seek to run trains as far north as possible (on both branches, even with CR2) with my GN&C scheme, but clearly Bowes Park's terminating siding can allow a 24tph+ through the core bit.

 

[si404]

This is an interesting idea to ponder on if I do say so myself. With the NCL, I wouldn't want to have its extension be popping out anywhere near Blackfriars, London Bridge, Elephant and Castle or Loughborough Junction, it should, ideally pop out going the other way, to not directly compete with the Thameslink Core and its 8 and 12 car trains.

Given the point of going that way is to expressly 'compete' with the over-crowded Northern line, what is wrong with 'competing'* as a concept?

Especially if they serve different areas in-between Finsbury Park and those southern areas: eg your route that goes towards West London passes right by an entrance to City Thameslink, but you dogma demands you don't create the interchange because you already have them at Stevenage, WGC, Finsbury Park, etc

*A better term might be complimenting.