Crossrail and Crossrail 2 tunnel lengths

[Busaholic]

I am sure this information is available with a bit of research, but just in case anyone has it to hand, I'm interested to know the relative lengths of continuous new tunnelling on Crossrail and on the proposed route(s) of Crossrail 2 - I know there are two alternatives for the south London section of the latter, so an answer giving both those would be great. Thank you in advance.

 

[rebmcr]

Given that multiple TBMs dug different stretches of the same Crossrail tunnel, your phrase 'continuous new tunnelling' is a bit ambiguous and could do with clarification.

 

[ijmad]

Not sure how reliable the source is, but this article says the Crossrail 2 tunnels would be 32km (2x16km).

Crossrail 1 core tunnel is 23km (2x11.5km), so quite a lot shorter, although there's also the Connaught Tunnel and the section under the Thames to Woolwich.

 

[TheKnightWho]

Not sure how reliable the source is, but this article says the Crossrail 2 tunnels would be 32km (2x16km).

Crossrail 1 core tunnel is 23km (2x11.5km), so quite a lot shorter, although there's also the Connaught Tunnel and the section under the Thames to Woolwich.

Crossrail 2 also comes in at over double the cost of Crossrail 1, so I'm not surprised at the increase in length! We'd also have to factor in the branch up to the ECML too, I suspect.

 

[Bald Rick]

Length of running line tunnels:

Crossrail 1 42km

Crossrail 2 74km - practically no difference between Balham and Tooting

 

[Busaholic]

Thank you all for your responses. I suspected that Crossrail 2's tunnels would be quite a bit longer than 1's, but hadn't realised an extra 32 km. I do hope they can get started soon, once the routeing has been finally confirmed. I know there are all sorts of parliamentary procedures and enquiries to be undergone but I'd like to think I might see it in operation before I kick the bucket!

 

[ijmad]

Crossrail 2 also comes in at over double the cost of Crossrail 1, so I'm not surprised at the increase in length! We'd also have to factor in the branch up to the ECML too, I suspect.

Good point, forgot about the Canal Tunnels. Were these budgeted under the St Pancras HS1 work?

Edit: Sorry, moron moment.

 

[Class 170101]

Good point, forgot about the Canal Tunnels. Were these budgeted under the St Pancras HS1 work?

Canal tunnels are nothing to do with Crossrail 2 it's part of Thameslink.

The branch to the ECML referred to is from Angel area to New Southgate.

 

[Mikey C]

That's a large increase in Tunnelling.

Ofsetting that cost, at least there won't be any electrification needed at either end

 

[59CosG95]

That's a large increase in Tunnelling.

Ofsetting that cost, at least there won't be any electrification needed at either end

Unless they suddenly decide to convert most of SW London to 25kV AC from 750v DC. I assume the changeover will happen at Wimbledon otherwise.

 

[Philip Phlopp]

Unless they suddenly decide to convert most of SW London to 25kV AC from 750v DC. I assume the changeover will happen at Wimbledon otherwise.

They might need to, 750V DC might not be capable of supplying enough power. It'll depend on stock requirements and service pattern.

 

[TheKnightWho]

Unless they suddenly decide to convert most of SW London to 25kV AC from 750v DC. I assume the changeover will happen at Wimbledon otherwise.

Considering it'll be opening in the early 2030s, there's a good chance we'll be seeing SWML conversion by that point.

 

[Bald Rick]

Considering it'll be opening in the early 2030s, there's a good chance we'll be seeing SWML conversion by that point.

No chance at all.

Changeover at Wimbledon, DC boosted where required.

 

[ijmad]

Canal tunnels are nothing to do with Crossrail 2 it's part of Thameslink.

The branch to the ECML referred to is from Angel area to New Southgate.

Sorry, moron moment.

 

[Domeyhead]

During Channel Tunnel construction when the TBMs completed their allocated bores they were slewed off to bore their own tombs then encased in concrete. Not sure if this being done for Crossrail 1 but as Crossrail 2 is now almost certain to go ahead I hope the TBMs will be dismantled resurfaced and refurbished for the new mission, rather than just providing yet another fat export contract for Herrenknecht.

 

[swt_passenger]

During Channel Tunnel construction when the TBMs completed their allocated bores they were slewed off to bore their own tombs then encased in concrete. Not sure if this being done for Crossrail 1 but as Crossrail 2 is now almost certain to go ahead I hope the TBMs will be dismantled resurfaced and refurbished for the new mission, rather than just providing yet another fat export contract for Herrenknecht.

There was no consistent rule for Crossrail 1. Some TBM cutter heads have been buried, and some were removed. The long train of equipment behind the cutting head is usually removed and recycled if possible though.

Within the overall costs of the whole multi-year project whether you can re-use the cutting heads is probably quite a trivial matter.

 

[Philip Phlopp]

There was no consistent rule for Crossrail 1. Some TBM cutter heads have been buried, and some were removed. The long train of equipment behind the cutting head is usually removed and recycled if possible though.

Within the overall costs of the whole multi-year project whether you can re-use the cutting heads is probably quite a trivial matter.

I don't know all the ins and outs of it, but some of the machines were due to go back to Herrenknecht for refurbishment, I think Herrenknecht had first refusal to buy back the machines if Crossrail didn't want them for Crossrail 2 or something along those lines.

 

[GRALISTAIR]

Unless they suddenly decide to convert most of SW London to 25kV AC from 750v DC. I assume the changeover will happen at Wimbledon otherwise.

They might need to, 750V DC might not be capable of supplying enough power. It'll depend on stock requirements and service pattern.

Considering it'll be opening in the early 2030s, there's a good chance we'll be seeing SWML conversion by that point.

No chance at all.

Changeover at Wimbledon, DC boosted where required.

Well I personally would never say never. If - and I agree a big if- Spine work is complete well before and thus some conversion experience from 750V DC 3rd rail to 25kV AC OHLE, I would say possible not "No chance at all"

 

[TheKnightWho]

Well I personally would never say never. If - and I agree a big if- Spine work is complete well before and thus some conversion experience from 750V DC 3rd rail to 25kV AC OHLE, I would say possible not "No chance at all"

I was thinking this. If Basingstoke-Southampton is converted, conversion of Basingstoke-Wimbledon and the Crossrail 2 branches follows naturally.

The real complexities begin when Clapham Junction comes into the mix, but that's thankfully circumvented here.

 

[jopsuk]

Apart from the yard connections, Clapham can more or less be considered as four seperate systems. The Southern tracks are independent, Windsor/Mainline are basically only connected because of the yard and Overground pretty much has a connection for engineering trains

 

[Philip Phlopp]

Well I personally would never say never. If - and I agree a big if- Spine work is complete well before and thus some conversion experience from 750V DC 3rd rail to 25kV AC OHLE, I would say possible not "No chance at all"

There's no urgency in any of this, Basingstoke to Southampton is a good scheme to begin with, but being realistic, we need to do more planning and testing at Old Dalby and High Marnham. The Crossrail 2 units will be dual voltage capable anyway, DC to AC conversion can be done whenever it's needed, without impacting on Crossrail 2 beyond engineering works.

The first 25kV electrification work on the South West region should be to equip the West of England main line with 25kV AC OLE, but that's a less complicated project, one voltage changeover at Basingstoke. It can happen at any time, it could be timed to coincide with life expiry of the existing DMU stock, or it could happen in the next Control Period, and the stock cascaded.

 

[GRALISTAIR]

The real complexities begin when Clapham Junction comes into the mix ---.

Oh yes sir - that would need the mother of all blockades I would think. 2 years advance notice - all commuters take your holidays then etc.

 

[Bald Rick]

Well I personally would never say never. If - and I agree a big if- Spine work is complete well before and thus some conversion experience from 750V DC 3rd rail to 25kV AC OHLE, I would say possible not "No chance at all"

Agreed never say never ... But ... its not going to happen before CR2. There's plenty of scope for uprating the DC where required.

Indeed aside from the Basingstoke - Southampton conversion, which is on the furthest most back burner (and the burner is set to gas mark 1), there are no plans for any DC to AC conversion. And no funding to look into it.

 

[ijmad]

They might need to, 750V DC might not be capable of supplying enough power. It'll depend on stock requirements and service pattern.

Thameslink will run 24tph x 12/8 carriages both ways through Blackfriars on third rail. It may not be as efficient but it seems to be able to supply enough power for that sort of intensive service pattern if required.

 

[Philip Phlopp]

Thameslink will run 24tph x 12/8 carriages both ways through Blackfriars on third rail. It may not be as efficient but it seems to be able to supply enough power for that sort of intensive service pattern if required.

It's not always the case that third rail is capable of supplying sufficient power to meet the required service pattern. There are a number of routes which have limited power available, which in turn limits train length or number of services.

 

[ijmad]

It's not always the case that third rail is capable of supplying sufficient power to meet the required service pattern. There are a number of routes which have limited power available, which in turn limits train length or number of services.

Humour me, but surely easier to upgrade the existing 3rd rail electrification than go to OHLE though?
I thought you were suggesting the only way to meet the power demands would be to go OHLE.

 

[HSTEd]

If it was really necessary to increase power the system could also sacrifice regeneration-to-the-grid and increase the third rail voltage to 850-900V at the substation.

 

[Philip Phlopp]

Humour me, but surely easier to upgrade the existing 3rd rail electrification than go to OHLE though?
I thought you were suggesting the only way to meet the power demands would be to go OHLE.

It might be easier, it depends on what power is available and where. It's not the best of ideas though, 750V DC is just so woefully inefficient. AC has losses of upto 5%, DC is upto 35%. That's electric being burned off into heat in cables, in the rails and in resistor grids during braking.

The existing third rail supply is based on a 33kV HV grid (Network Rail's grid, incidentally) which supplies to the 750V substations that feed the third rail.

If the 33kV grid doesn't have the capability to supply more substations, then 750V DC won't be able to provide the required power to meet the service requirements. That's the case in some areas, lack of 750V sub stations is an issue elsewhere.

There are three options, depending on what the precise power supply problem is - it could be as simple as providing more 750V DC feeders, it could need an upgrade to the 33kV grid to enable more 750V DC feeder stations, or move to 25kV AC with Auto Transformer Feed if required, particularly if it's not possible to do more with the 33kV grid.

If you're going to spend £26bn on Crossrail 2, it might be worth allocating a small amount extra to provide 25kV AC OLE on the full route, pretty much every unit working in the south by the time Crossrail 2 is completed will be 25kV compatible. Might be is the operative phrase here.

 

[najaB]

IIf you're going to spend £26bn on Crossrail 2, it might be worth allocating a small amount extra to provide 25kV AC OLE on the full route, pretty much every unit working in the south by the time Crossrail 2 is completed will be 25kV compatible. Might be is the operative phrase here.

I'd say that it is worth it, if only because it means you don't have to maintain two different electrification standards on the route. Plus a lot of the third-rail equipment has got to be getting close to needing renewal by then anyway.
--- old post above --- --- new post below ---
Apropos of nothing, but I only just noticed that Crossrail 2 has a Euston-St Pancras station - does that mean the full name would be Euston-St Pacras-Kings Cross?
--- old post above --- --- new post below ---
To the OP, you can get a good idea of the planned route(s) for the tunnel(s) from the Crossrail 2 safeguarding map.

 

[Busaholic]

No chance at all.

Changeover at Wimbledon, DC boosted where required.

Will there be an extra pair of tracks where the changeover takes place so that the running tracks don't get blocked (unlike Thameslink) whenever it goes wrong? Money well-spent, I'd have thought.