Was the HS2 Chiltern Tunnel necessary?

[Nottingham59]

Yes but the ever so wise government let the contracts on a cost-plus basis, so the actual cost is likely to be considerably higher

Yes. But even if the out-turn cost is double that, it's still a small part of the whole. It's frustrating that there is no visibility of the drivers of cost in the accounts.

 

[Transilien]

The Chipping Warden and Greatworth tunnels are both enormous undertakings for seemingly very little benefit at all.

HS2 in a nutshell in its current state!

 

[titus]

Yes but the ever so wise government let the contracts on a cost-plus basis, so the actual cost is likely to be considerably higher

Cost’s haven’t really risen more than construction inflation since the gov signed off on in it early 2020 (other than Euston project) If it had been a fixed cost, they would have had to increase it anyway, otherwise contractors would have just collapsed. The problems seem to have come more in the planning stage

 

[stuu]

Cost’s haven’t really risen more than construction inflation since the gov signed off on in it early 2020 (other than Euston project) If it had been a fixed cost, they would have had to increase it anyway, otherwise contractors would have just collapsed. The problems seem to have come more in the planning stage

Steel has more than doubled in price, so I'm not sure that's true. And yes, the contractors couldn't have borne the cost of those increases, but that wasn't the point, the point was that the contract price at award is nothing like the same as the actual outturn cost.

I did wonder how it is accounted, but Align don't publish their accounts and HS2 only publish a figure for total capital expenditure (nearly £7bn in 2022/23). Presumably at some point the actual cost of each contract will be revealed though

 

[Bald Rick]

The other aspect to remember is that, surprisingly, building tunnels is not the biggest cost incurred by HS2.

The main civil engineering contract C1 to build the Chiltern tunnels and the Colne Valley viaduct (22km of line), was awarded in July 2017 to the ALIGN Joint Venture for a cost of £965 million. That's £44m per route km.

At that rate per km, a twin-track tunnel all the way from the portal at Euston direct to Birmingham Interchange (147km) would have cost £6.5 billion. Even allowing for construction inflation since 2017, the outturn cost today of a London-Birmingham tunnel would have been of the order of £10-£12bn.

It's easy to blame unnecessary tunnelling costs on the ballooning cost of HS2, but it's more complicated than that.
Personally I don't understand where the money has gone. And HS2 and DfT seem very reluctant to publish sufficiently detailed accounts to explain how the whole project is going to cost around £250M per route km.

See: https://www.rendel-ltd.com/news/view/align-consortium-is-awarded-a-flagship-hs2-civil-works-contract

You are conflating the contract costs for one part of building that section of railway at the time the contract was signed with the total costs of building that section of railway.

 

[HSTEd]

Steel has more than doubled in price, so I'm not sure that's true. And yes, the contractors couldn't have borne the cost of those increases, but that wasn't the point, the point was that the contract price at award is nothing like the same as the actual outturn cost

The cost of commodity products like steel and concrete are only a very small portion of the costs of these projects.

Otherwise, the idea that NIMBY demanded tunneling is a major cost driver is attractive to many, but I'm not sure it's a particularly strong argument.

HS2 is projected to require a million tonnes of steel, the vast majority of which will be grades traded globally and in vast quantities. This is only a very small portion of even the original budget.

 

[masekwm]

This tunnel is the most ludicrous example overengineering HS2 to appease NIMBYs

I've filmed a lot of the sites so far, but the green tunnels make little sense, the one running through Chipping Warden surrounded by the old airfield adds nothing to the project.

 

[furnessvale]

On the other hand, noone will remember the money that was saved by using these politically fraught, but notionally less expensive, solutions either.
The impacts of the railway on the landscape (and any destruction of forests dating to time immemorial) will endure forever.

Given that HS2 has been drastically scaled back, and HS3-6 (whatever they could have been) are history, all due in no small part to nimby induced cost escalation, the resultant increase in roads and traffic needed to carry those passengers and freight will have a far greater impact enduring for ever.

 

[HSTEd]

Given that HS2 has been drastically scaled back, and HS3-6 (whatever they could have been) are history, all due in no small part to nimby induced cost escalation, the resultant increase in roads and traffic needed to carry those passengers and freight will have a far greater impact enduring for ever.

I'm not sure HS2 could have selected a route better calibrated to pick a fight with environmentalists and anti construction campaigners than the one they chose.

I've not seen much evidence that NIMBYs were responsible for a large fraction of the cost growth on HS2. Indeed it seems to be the same old failures that cause runaway cost growth on other British infrastructure projects. The cost overruns far exceed the cost of extra tunneling and the like.

In any case, HS2 selected a route that required them to fight an unwinnable political battle.

 

[dosxuk]

I've filmed a lot of the sites so far, but the green tunnels make little sense, the one running through Chipping Warden surrounded by the old airfield adds nothing to the project.

Doesn't make much sense from above - the horizontal profile - but it certainly does on the vertical profile. If it was an open cutting, it would be over 80 feet deep, requiring a huge area to be taken over for the banks, and require a huge amount of material to be transported away from the site.

For areas where the line passes through ridges and small hills, cut-and-cover tunnels can be more economical than a cutting - and if not in the short term then certainly in the long term. Large embankments and cuttings cost a lot of money to maintain.

 

[edwin_m]

Doesn't make much sense from above - the horizontal profile - but it certainly does on the vertical profile. If it was an open cutting, it would be over 80 feet deep, requiring a huge area to be taken over for the banks, and require a huge amount of material to be transported away from the site.

For areas where the line passes through ridges and small hills, cut-and-cover tunnels can be more economical than a cutting - and if not in the short term then certainly in the long term. Large embankments and cuttings cost a lot of money to maintain.

However, to build a cut and cover tunnel you have to dig that cutting anyway. So the capital cost savings are limited to not taking most of the earth off site (but having to put it back instead) and any dimensions that can be reduced by treating it as a temporary cutting rather than a permanent one. It does of course mean that the land can be used for other things instead of being permanently part of the railway earthworks, and I agree the maintenance costs of the earthwork are avoided - but a tunnel has some operating and maintenance costs too.

 

[LNW-GW Joint]

Yes but the ever so wise government let the contracts on a cost-plus basis, so the actual cost is likely to be considerably higher

I think the tunnelling contracts actually had some element of cost control, because TBM tunnelling is a reasonably well-understood process.
It's likely the deep excavations at places like Euston and OOC that weren't controlled, as the contractors would not take the risk of finding difficult ground.
Similarly the Colne Valley viaduct was a largely understood environment (though it has taken longer to build than planned).
Happy to be corrected on any of these.
We are also now 20 months late on awarding any of the railway contracts, which are subject to high inflationary pressures before the work even starts.

 

[Meerkat]

We need more green tunnels and bridges - they dramatically reduce the impact on local people and create wildlife corridors across infrastructure.