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HS2 - slowing down

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MarlowDonkey

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The Mail has a report that there's a proposal to slow down HS2. Specifically tunnels can be cheaper if they are designed with a lower maximum speed than previously proposed. I think there was something similar to save money during the construction of the Channel Tunnel. There's a lot of proposed tunnel on HS2 though.
 
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PeterC

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I strongly suspect that some of the environmental mitigation will go by the board.
 

kylemore

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Well once we're through a hard/clean Brexit and we have a right wing Tory govt under Rees Mogg or the worker's paradise under Corbyn and McDonnell the HS2 will be "slowed down" permanently!:smile:
 

PHILIPE

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The Mail has a report that there's a proposal to slow down HS2. Specifically tunnels can be cheaper if they are designed with a lower maximum speed than previously proposed. I think there was something similar to save money during the construction of the Channel Tunnel. There's a lot of proposed tunnel on HS2 though.

Slow down ? Might as well get rid of the ever increasing over budget cost of this Vanity project once and for all
 

NSEFAN

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The Mail has a report that there's a proposal to slow down HS2. Specifically tunnels can be cheaper if they are designed with a lower maximum speed than previously proposed. I think there was something similar to save money during the construction of the Channel Tunnel. There's a lot of proposed tunnel on HS2 though.
Do you have a link to the report itself?
 

Bletchleyite

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I can see that going for 186mph (300km/h) would be sensible, that makes it a conventional French or German-style LGV and will also make the trains a lot cheaper while still providing the south WCML capacity needed.
 

Maurice3000

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Do you have a link to the report itself?
I can see that going for 186mph (300km/h) would be sensible, that makes it a conventional French or German-style LGV and will also make the trains a lot cheaper while still providing the south WCML capacity needed.
I don't do links to the Daily Heil but here is an alternative source that also talks of reducing top speed by "30mph" (I assume they mean 50 km/h) so in real terms that would likely mean a top speed of 320 km/h. From a rolling stock perspective 320 km/h is the typical first level below the 360 km/h level so that would make sense. Quite a few manufacturers have 320 km/h models in their portfolio so it could be a relatively off-the-shelf purchase.

What doesn't really make sense is the confusion between design speed and rolling stock speed. Changes to make the tunnels cheaper have nothing to do with rolling stock speed and everything to do with design speed. And as far as I'm aware the design speed is 400 km/h (as you'll want to build this thing for at least a century). Does that mean the design speed would be lowered to 350 km/h (400-50) or are we really talking about reducing design speed from 400 km/h to 320 km/h?
 
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LNW-GW Joint

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They are also considering using ballasted track in the tunnels instead of slab track.
Cheaper to build but more expensive to maintain long term.
The de-speccing is to said to be so the project remains within its cost/time parameters and to avoid a "Crossrail" problem.
It won't so anything of the sort, of course, it will be 5-8 years before the real cost outturn for HS2 will become apparent.
But it would take the heat out of the current political issues.
The report comes from a parliamentary group after a meeting with Mark Thurston, HS2 CEO.
This is the Guardian's version: https://www.theguardian.com/uk-news...-slower-trains-to-stay-on-budget-and-schedule
HS2 could be forced to run fewer trains and at slower speeds in order to keep the high-speed rail project within budget, the company’s chief executive has said.

The economising options discussed included potentially lowering train speeds of up to 225mph (360km/h) by about 30mph, changing from a slab to a ballast track and reducing the number of trains per hour from 18 to 14, according to the MP for South Northamptonshire, an area through which the HS2 route will pass.
 
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Maurice3000

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They are also considering using ballasted track in the tunnels instead of slab track.
Cheaper to build but more expensive to maintain long term.
My first thought would be to try and keep the tunnel design as it is and indeed get savings on things such as ballast instead of slab track. In 20 or 30 years you could always decide to upgrade the ballast to slab whereas rebuilding tunnels would be a lot harder and probably will never happen. But then, I am not a civil engineer...
 

mrmartin

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Not too bothered about the top speed - it will only be reached very rarely with the acceleration required to get up to those speeds, but the news about fewer trains running per hour is disappointing. Cutting 25% of the capacity off probably means some direct routes won't use HS2. Also seems like a false economy, eg Pendolino fleet being 9 car to then spend a load of cash to upgrade to 11 car a ~decade later?
 

LeeLivery

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Is this the second planned speed reduction then? 320km/h always made sense, the international standard, almost out of the box trains and energy efficient. The route just isn't long enough to need 360km/h, let alone 400.

As for the frequency reduction, I never believed 18tph would ever use the route anyway.

Add a sweetener for South Northants and build a rural French TGV style station in Brackley.
 

AndrewE

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What would it look like if it was optimised for capacity? Presumably higher speeds need longer headways, hence signal section lengths... So could this de-speccing actually make our new fast relief line more useful (or delay the day when it too gets full?)
(is this why French TGVs and Eurostars are such long trains - by our standards?)
 

Bletchleyite

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Interestingly with the ICE4 Germany is moving towards a *lower* top speed of 250km/h, citing connectivity, the environment and cost as more important than raw speed.

Personally I'd say speccing it all to 300km/h per HS1 would be a sensible balance.
 

Mollman

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The HS2 top speed was always political vanity with most respectable commentators calling for a lower speed. Perhaps they have accepted the recommendations of the Greengauge 21 report.
 

The Planner

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Not sure why they would go back to ballast as it would be a false economy as they will be replacing it pretty much constantly, unless its a capex opex thing.

As for optimising capacity, a 3 minute headway on a high speed route isnt something to be considered poor.
 

LNW-GW Joint

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With ETCS it shouldn't cost much to reconfigure the signalling to whatever capacity is needed.
There won't be the scale of fixed equipment which is so expensive to alter on classic lines.
Trains will be 200m/400m long so large by GB standards when doubled up, similar to 2xTGV/ICE or 1xEurostar.
 

takno

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As far as I could make out from the Guardian report, the head of HS2 had a chat with a group of MPs (not a committee), where he outlined some of the things they could do if things start running over budget (the overall budget being seen as increasingly sacrosanct rather than delivery of the whole project as specced). Andrea Leadsom, who is part of the group and mostly opposes HS2 because it goes through her constituency, then span it as a definite plan to make all manner of cuts because the project is definitely over budget. The Guardian, and apparently the Mail then seem to have swallowed it whole, probably because it suits the line both have been pushing all along.

I could have misread it of course
 

mallard

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More bad news for the MML then, since that line has already been slowed down and had upgrades cancelled to try to boost the benefits of HS2... Who still claim the fastest current London-Nottingham time is 1hr44 (it's 1h38 even with the recent downgrades) and that it's going to be possible to get from Toton to Nottingham in 17 minutes (presumably that's been calculated with zero interchange time). With more correct/reasonable numbers, HS2 will save no more than 10 minutes for Nottingham passengers, which means many passengers will likely prefer the "classic" route that doesn't require a change. Since the eastern arm frequency seems to be planned at only 2tph, there will definitely be departure times where leaving "now" via the classic route will be faster than waiting for the HS2 service.

If they're going to slow down HS2, then MML is going to be downgraded further. I wonder if we'll even have >100mph rolling stock in a decade or two... Don't forget that slowing the MML degrades service to destinations (e.g. Leicester) that won't benefit from HS2, so there are few "winners" with DfT's current bloody-mindedness over the East Midlands.
 

tasky

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Interestingly with the ICE4 Germany is moving towards a *lower* top speed of 250km/h, citing connectivity, the environment and cost as more important than raw speed.

Personally I'd say speccing it all to 300km/h per HS1 would be a sensible balance.

People mention this a lot but it is slightly misleading, as I understand it the ICE4 EMUs are mostly to replace the loco-hauled IC services rather than ICE3
 

gsnedders

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They've also ordered a load more to replace ageing ICEs.
To replace ICE1 (ICE4 has the same top-speed at ICE1; 250km/h) and ICE2s (280km/h). Both, AIUI, primarily run on routes where the top speed is 250km/h nowadays.
 

Starmill

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I can see that going for 186mph (300km/h) would be sensible, that makes it a conventional French or German-style LGV and will also make the trains a lot cheaper while still providing the south WCML capacity needed.
The new French LGVs are speecced at 320 km/h, which they see as the best balance between the cost in energy and maintenance requirements and journey times on offer.

The Germans have relatively few routes where trains can run at even 300km/h, preferring more "connectivity" in exchange for longer journey times.

To me it makes very little sense not to organise the infrastructure for up to 400 km/h, which is long term where the technology could head. In the short term there is probably no need for trains to run amy faster than 320.
 

ABB125

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Personally I think that a good compromise would be a design speed of 360km/h rather than 400, and an initial train maximum speed of 320km/h. This would then allow easy purchase of "off the shelf" high-speed stock (albeit complicated by our loading guage for classic compatible), and, although it will undoubtedly be too late for phase one, potentially allow the route to change a bit, eg: around rather that through that bit of irreplaceable ancient woodland, or to follow existing transport corridors more closely through sensitive areas. Hopefully some of this could be applied to phase two (b).
 

gsnedders

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The new French LGVs are speecced at 320 km/h, which they see as the best balance between the cost in energy and maintenance requirements and journey times on offer.
LGV Est has a design speed of 350km/h (which I think includes the signalling, OHLE, etc.), though the service speed is only 320km/h (due to those trade offs), and the stock is designed for a top speed of the service speed.

Personally I think that a good compromise would be a design speed of 360km/h rather than 400, and an initial train maximum speed of 320km/h. This would then allow easy purchase of "off the shelf" high-speed stock (albeit complicated by our loading guage for classic compatible), and, although it will undoubtedly be too late for phase one, potentially allow the route to change a bit, eg: around rather that through that bit of irreplaceable ancient woodland, or to follow existing transport corridors more closely through sensitive areas. Hopefully some of this could be applied to phase two (b).
How much of the cost is down to the design speed, and how much of the cost is down to the service speed? Without that I don't think we can make an informed decision here. I'd always be in favour of over-specifying the infrastructure (and the alignment especially) and being vastly more conservative with the rolling stock (because replacing rolling stock is comparatively cheap).
 
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The obvious way to cut costs substantially and reduce construction time by years, is to reduce the crazy amount of tunnelling, and put it on the surface. They did it in the 60s and built the M1 in a fraction of the time this is going to take. Madness.
 

Ianno87

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The obvious way to cut costs substantially and reduce construction time by years, is to reduce the crazy amount of tunnelling, and put it on the surface. They did it in the 60s and built the M1 in a fraction of the time this is going to take. Madness.

The M1 starts at Brent Cross, not Euston station!
 

ABB125

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LGV Est has a design speed of 350km/h (which I think includes the signalling, OHLE, etc.), though the service speed is only 320km/h (due to those trade offs), and the stock is designed for a top speed of the service speed.


How much of the cost is down to the design speed, and how much of the cost is down to the service speed? Without that I don't think we can make an informed decision here. I'd always be in favour of over-specifying the infrastructure (and the alignment especially) and being vastly more conservative with the rolling stock (because replacing rolling stock is comparatively cheap).
Yes, that is a good point, but unfortunately I don't really know. If I were in charge, I would have a policy of building to the maximum possible speed (within reason of course, although we then get to the argument of whether 400km/h is reasonable), reducing where necessary based upon the potential cost savings, environmental impact and one which I think is often overlooked, how long it will take for the trains to accelerate back to the maximum speed after the reduced section (although this isn't generally a problem if you have 250mph track but only 200mph trains!).
 

AndrewE

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(because replacing rolling stock is comparatively cheap).
Except that on today's UK railway we can't even consider doubling (or tripling) up train capacity on key routes where the infrastructure allows it in response to demand because the Franchise / TOC / ROSCo contracts are so inflexible (or operated to extract every possible pound of flesh if change is needed) that it just can't be done.
Even franchise commitments to increasing capacity are treated as optional by whoever is pretending to be in charge: I'm remembering TPE not bothering to use the Mk 3 sets they promised - or were required - to put into use, plus more than 1 experience of being left behind in Leeds and abandoning hope and coming back for a train an hour later.
Some highly-qualified people here point out that trains are relatively cheap but infrastructure is a lot more expensive... so why are TPE trains still only 3-cars? Please don't tell me we are going to get "jam tomorrow," we have been waiting about 5 years (or more) already...
 
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