What is the maximum feasible loading gauge on the Jubilee Line Extension?

[Rumblr]

Maybe a silly question but what is the maximum feasible loading gauge on the Jubilee Line Extension between Stratford and Westminster if you discount through running to the older sections beyond Green Park?

The tunnel diameter is 4.35m which is slightly smaller than the diameter of the Northern City Line at 4.95 and Tyne and Wear Metro at 4.75m so the broader question is whether larger rolling stock could theoretically run on the JLE line if for example in future the line was ever decoupled from the original Fleet line section.

For example, if in a hypothetical scenario, you built a new tunnel from Baker Street to Green Park, could you run Metropolitan line S Stock on the JLE to Stratford and return the deep level trains to run Stanmore to Charing Cross on the old Fleet Line route.

 

[SynthD]

The extension was also built with a wider tunnel diameter of 4.35 m allowing a passenger walkway used for emergency purposes; unfortunately wider trains are not possible due to the narrower tunnel dimension northwards of Green Park.

Wikipedia and all I’ve ever heard implies that the extra width is entirely used up by the walkway.

 

[Mr. SW]

I think the track is offset from the centre line as well. I've looked a couple of cab ride videos and it appears to be about 150 to 200 mm (6 to 8 in) (videos very indistinct), so no Met trains without a significant all line refit, so it's a non-starter.

I did toy some years ago with the thought that it would be possible to split the Jubilee line at Green Park/Westminster and create two new (half lines) from it. The northern section from Stanmore would be redirected back through to Charing Cross and then extended first into the City as far as Cannon Street before turning south to serve such areas as Peckham Rye, Gypsy Hill, Thornton Heath and Croydon. The other section goes west to serve Knightsbridge, High Street Ken and Kensington Olympia before going more directly west to serve, in essence, the same areas as the abortive West London Tram, Shepherds Bush, Acton, Southall, Hayes and Uxbridge, thus also acting as a sort of six-tracking substitute for the Great Western Main Line.

Crayons back in box. Click.

 

[BerkshireRails]

I think the track is offset from the centre line as well. I've looked a couple of cab ride videos and it appears to be about 150 to 200 mm (6 to 8 in) (videos very indistinct), so no Met trains without a significant all line refit, so it's a non-starter.

I did toy some years ago with the thought that it would be possible to split the Jubilee line at Green Park/Westminster and create two new (half lines) from it. The northern section from Stanmore would be redirected back through to Charing Cross and then extended first into the City as far as Cannon Street before turning south to serve such areas as Peckham Rye, Gypsy Hill, Thornton Heath and Croydon. The other section goes west to serve Knightsbridge, High Street Ken and Kensington Olympia before going more directly west to serve, in essence, the same areas as the abortive West London Tram, Shepherds Bush, Acton, Southall, Hayes and Uxbridge, thus also acting as a sort of six-tracking substitute for the Great Western Main Line.

Crayons back in box. Click.

Wouldn't a better option just to six track Great Western Mainline between Paddington and Airport Junction, to kick the Elizabeth Line stoppers (Heathrow and West Drayton services) on to there own lines to allow the GWR 387s to work on the Reliefs and keep the Mains just for the IETs.

 

[Mr. SW]

Wouldn't a better option just to six track Great Western Mainline between Paddington and Airport Junction, to kick the Elizabeth Line stoppers (Heathrow and West Drayton services) on to there own lines to allow the GWR 387s to work on the Reliefs and keep the Mains just for the IETs.

I know the area very well. That ain't 'appenin'.

 

[Class15]

Wouldn't a better option just to six track Great Western Mainline between Paddington and Airport Junction, to kick the Elizabeth Line stoppers (Heathrow and West Drayton services) on to there own lines to allow the GWR 387s to work on the Reliefs and keep the Mains just for the IETs.

There’s absolutely no room for this unless it’s tunnelled and at that point it’s just easier to build a separate tube line.

 

[BerkshireRails]

There’s absolutely no room for this unless it’s tunnelled and at that point it’s just easier to build a separate tube line.

Putting it underground would enable a more reliable Elizabeth Line services to Heathrow Airport as well as reducing overcrowding on some Elizabeth Line services as more services would continue to Heathrow Airport. It could arguably have a better business case than a new tube line from Paddington to Hayes and Harlington. It would also simplify calling patterns with Reading/Maidenhead running semifast and Heathrows run all stops.

 

[zwk500]

Wouldn't a better option just to six track Great Western Mainline between Paddington and Airport Junction, to kick the Elizabeth Line stoppers (Heathrow and West Drayton services) on to there own lines to allow the GWR 387s to work on the Reliefs and keep the Mains just for the IETs.

'just' is doing an *extraordinary* amount of heavy lifting there.

 

[stuu]

Wouldn't a better option just to six track Great Western Mainline between Paddington and Airport Junction, to kick the Elizabeth Line stoppers (Heathrow and West Drayton services) on to there own lines to allow the GWR 387s to work on the Reliefs and keep the Mains just for the IETs.

In the incredibly unlikely case of extra tracks on the GWML, moving the fasts into a tunnel would be the sensible option as it avoids the cost of stations

 

[BerkshireRails]

In the incredibly unlikely case of extra tracks on the GWML, moving the fasts into a tunnel would be the sensible option as it avoids the cost of stations

I rulled out putting the mains underground because of the approach into Paddington. The Elizabeth Line Heathrow services make sense as you can then have fully grade separated junctions, which you would struggle to do with the mains. Plus the Up Relief, Down Relief, Up Main, Down Main doesn't lend itself to having trains frequently crossing over which would be required to put the Mains underground.

 

[Crithylum]

I rulled out putting the mains underground because of the approach into Paddington. The Elizabeth Line Heathrow services make sense as you can then have fully grade separated junctions, which you would struggle to do with the mains. Plus the Up Relief, Down Relief, Up Main, Down Main doesn't lend itself to having trains frequently crossing over which would be required to put the Mains underground.

This is very much drifting off topic, but I suspect that they would pop back above ground a bit west of Old Oak Common. East of there to Paddington is kinda 6 track already, if you repurpose some sidings and move stuff like the train wash

 

[Mr. SW]

If you're going to build tunnels, it would be easier just to link them with the Tube system and then use the line and stations in a way to tap the short distance local traffic leaving the GWML/EL for the passengers who want a speedier way to get about.

It's all very well, fine and dandy talking about super-duper tunnels, shiny grade-separated junctions with escape and ventilation shafts etc, but think about where you would put them and the geography, geology, topography and demography of the immediate area.

Don't forget the Brent Valley, while not exactly Alpine in nature, is a significant obstacle, hence the Wharncliffe and Piccadilly Line Viaducts.

With a tube line and its closely-spaced stations, you can take the tunnels almost anywhere you like without significant obstruction and the ventilation points are incorporated into the stops by default and maybe an easier sell when going through places like Ealing.

Anyway, gone seriously off topic now.

The answer still stands, Met stock will not fit the Jubilee line extension tunnels.

 

[ShadowKnight]

Would it be worth widening any of the tube tunnels to a larger loading gauge? I presume not but it has been done before on the original city and South London railway (northern line Stockwell to London bridge)

 

[AlastairFraser]

I rulled out putting the mains underground because of the approach into Paddington. The Elizabeth Line Heathrow services make sense as you can then have fully grade separated junctions, which you would struggle to do with the mains. Plus the Up Relief, Down Relief, Up Main, Down Main doesn't lend itself to having trains frequently crossing over which would be required to put the Mains underground.

If there is likely to be any major further improvements to the GWML, it is much more likely to be a HS4 taking high speed services from London to South Wales/Devon and Cornwall/the West Country. Such a line would be better tunnelled out to south of Hayes, where it can follow the M4 towards the South West.
A tunnel for suburban services west of Paddington (or, more accurately, Royal Oak), can't be justified for the additional services that could possibly be operated based on feasible growth in passenger numbers.

Now, if you wanted extra capacity and more trains to Heathrow, a frequent suggestion and a much easier plan would be to either 1) extend Heathrow Express through to south/west of Heathrow using the proposed Southern/Western Access - in order to justify their presence on the GWML, based on average passengers through to central London from non-Heathrow destinations bolstering the passenger numbers or 2) replace Heathrow Express with Elizabeth Line services that also likely extend through to the Western/Southern access routes and increase capacity to attract more passengers in a similar way.

 

[Rumblr]

I think the track is offset from the centre line as well. I've looked a couple of cab ride videos and it appears to be about 150 to 200 mm (6 to 8 in) (videos very indistinct), so no Met trains without a significant all line refit, so it's a non-starter.

I did toy some years ago with the thought that it would be possible to split the Jubilee line at Green Park/Westminster and create two new (half lines) from it. The northern section from Stanmore would be redirected back through to Charing Cross and then extended first into the City as far as Cannon Street before turning south to serve such areas as Peckham Rye, Gypsy Hill, Thornton Heath and Croydon. The other section goes west to serve Knightsbridge, High Street Ken and Kensington Olympia before going more directly west to serve, in essence, the same areas as the abortive West London Tram, Shepherds Bush, Acton, Southall, Hayes and Uxbridge, thus also acting as a sort of six-tracking substitute for the Great Western Main Line.

Crayons back in box. Click.

I think you are right, I found a diagram here which seems to suggest the gap to the top of the tunnel is similar to the Victoria Line. The extra space gained from the larger diameter seems to be used to backfill the ground to a higher level to create the escape walkway.




In terms of splitting and extending the Jubilee, I wonder would it be better to just build a completely new line in that scenario? At Greenpark, you will need to build a new platforms and approaches to allow a cross platform interchange with the existing Jubilee and you will need to build new tunnels West of Green Park and East of Charing Cross to a standard similar to the Northern Line Extension. For the extra cost of widening the Fleet Line stub tunnels at Charing Cross, you could benefit from larger rolling stock and having fully driverless trains and increased choice in platform length and rolling stock. If you split the jubilee, you be stuck with deep level tube stock on a considerable length of new tunnels.

 

[BerkshireRails]

I think you are right, I found a diagram here which seems to suggest the gap to the top of the tunnel is similar to the Victoria Line. The extra space gained from the larger diameter seems to be used to backfill the ground to a higher level to create the escape walkway.

View attachment 186919


In terms of splitting and extending the Jubilee, I wonder would it be better to just build a completely new line in that scenario? At Greenpark, you will need to build a new platforms and approaches to allow a cross platform interchange with the existing Jubilee and you will need to build new tunnels West of Green Park and East of Charing Cross to a standard similar to the Northern Line Extension. For the extra cost of widening the Fleet Line stub tunnels at Charing Cross, you could benefit from larger rolling stock and having fully driverless trains and increased choice in platform length and rolling stock. If you split the jubilee, you be stuck with deep level tube stock on a considerable length of new tunnels.

They went for a slightly larger internal diameter of 6.2 metres in the end for Crossrail.

 

[Mr. SW]

If you split the jubilee, you be stuck with deep level tube stock on a considerable length of new tunnels.

Which is almost certainly why it'll never happen.

On the other hand, tube size clearances and infrastructure allow you to do things that would otherwise be barred such as compact grade separation, tight curvature etc. And I doubt that anyone would travel on an extended Jubilee line from Hayes and Harlington to Stratford by preference unless something very unusual happened.

 

[BerkshireRails]

Which is almost certainly why it'll never happen.

On the other hand, tube size clearances and infrastructure allow you to do things that would otherwise be barred such as compact grade separation, tight curvature etc. And I doubt that anyone would travel on an extended Jubilee line from Hayes and Harlington to Stratford by preference unless something very unusual happened.

Especially considering Elizabeth Line and Great Western Railway services both do 90mph and a tube line would probably be limited to 45-62mph. Wouldn't it be better to move the Elizabeth Line discussion to the Great Western Mainline Elizabeth line thread?