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What’s your thinking there? The bigger tunnel boring machines needed and the extra dirt excavated are cheap in the bigger picture. The trend is clear within Lon

What’s your thinking there? The bigger tunnel boring machines needed and the extra dirt excavated are cheap in the bigger picture. The trend is clear within London alone and globally, towards larger tunnels.

s1artibartfast 3y ago
How are they cheap in the big picture? Average cost is a billion per mile in the US and the latest numbers out of New York are more than 5 billion per mile. Vegas hyperloop was <30 million per mile, so somewhere between 3% and 0.6% the cost per mile. Reportedly, in this expansion, private companies will carry the entire cost.
- matthewdgreen 3y ago
  Most of that high cost isn't due to the use of specific tunnel boring machines. In Europe they pay 1/6th of the US cost and still dig much wider tunnels with multiple tracks that support higher-capacity trains and safety features that the Vegas tunnels lack.
  - s1artibartfast 3y ago
    I agree that there are a lot of reasons for the cost differential between the US and Europe, and many reports and papers on the topic. From what I've read, tunnel costs are climbing quickly in Europe. At the end of the day The boring company seems to be able to avoid these high costs using a combination of their technology, simplified goal, and business approach while nobody else has been able to bring costs down for a large tunnels in the US. It would be great if someone could figure out how to bring large Tunnel cost down in the US, but until someone does, smaller tunnels costing a few percent of the cost have a competitive advantage. My understanding is that the problems driving large tunnel construction costs in the US are driven by a shortage of labor expertise, Labor bloat compared to other countries, and institutional inability to manage large projects and avoid scope change.
    - deleted 3y ago
      [deleted]
    - abduhl 3y ago
      >> My understanding is that the problems driving large tunnel construction costs in the US are driven by a shortage of labor expertise, Labor bloat compared to other countries, and institutional inability to manage large projects and avoid scope change. This understanding is not correct. America's tunneling cost problem is driven by labor costs, unions, politics, and third party litigation. The institutional inability to manage large projects is a result of the latter three of these: the people in charge when the contract is signed are often not the people in charge when the job is half completed, and that change in leadership leads to scope changes that should (justifiably) be paid for.
      - s1artibartfast 3y ago
        I dont see a meaningful distinction between the causes you claim and what I said. I agree third party litigation warrants highlighting, but I consider that as part of institutional inability to manage large projects. Likelwise, I see high labor costs and unions as equavalent to lack of skilled labor and bloated labor costs. At the end of the day, we are saying the same thing. Cost of workers is higher, the US uses far more workers, and the US legal and political systems are not condusive to efficient execution.
        abduhl 3y ago
        Your articulation is not unique to large diameter tunnels, the generic costs you point to are endemic to any diameter tunnel in America and also to any infrastructure project in America that takes place in an urban environment. To say that these things are a "large diameter tunnel" problem is to miss the unique distinctions between TUNNELING costs and INFRASTRUCTURE costs in America. At a high level we agree, but that's not useful for finding a solution to the specific problem of American tunneling costs. For example, the labor shortage impacts all construction in America but tunnels require even more specialized laborers. Unions drive up the cost of all construction in America, but specific unions (like the Sandhogs) have specific provisions in their contracts that drive up the cost even more. Scope changes impact all construction, but scope changes underground cost orders of magnitude more than surface scope changes (add an offramp above ground versus add an offramp underground). Third party litigation impacts all construction, but the nature of tunneling increases the risk of third party litigation because settlement/sinkholes can occur vast distances away from the work.
- tobylane 3y ago
  Digging a wider tunnel requires a bigger tbm, which adds little to the whole cost. Hs2 put out a paper, though I don’t think it compares sizes. https://assets.publishing.service.gov.uk/government/uploads/ https://assets.publishing.service.gov.uk/government/uploads/... The NYC example is terrible, because the new part of the tunnel is only short and the whole project costs a lot does not mean each mile of the tunnel costs that much. I was first asking why they thought small tunnels are better, is that purely on financial grounds? Low cost, low benefit.
  - s1artibartfast 3y ago
    Why is it not appropriate to compare a whole project cost the whole project cost per mile? The New York extension was 7.7 billion for 1.5 MI and the Vegas Loop was 47 million for 1.7 MI. Now you have a project cost per mile and you can evaluate benefit from per mile. Biggest Loop was unquestionably much lower total benefit. Then you can compare benefit per dollar. At 1 200th the price does it provide more or less than 0.5% the value.
beowulfey 3y ago
I guess my thinking was that it works pretty well in London to use smaller tunnels, and I don't immediately understand why larger tunnels are needed. If you're familiar with why tunnels have been trending larger, I'd love to know.

s1artibartfast 3y ago

How are they cheap in the big picture? Average cost is a billion per mile in the US and the latest numbers out of New York are more than 5 billion per mile. Vegas hyperloop was <30 million per mile, so somewhere between 3% and 0.6% the cost per mile. Reportedly, in this expansion, private companies will carry the entire cost.

matthewdgreen 3y ago
Most of that high cost isn't due to the use of specific tunnel boring machines. In Europe they pay 1/6th of the US cost and still dig much wider tunnels with multiple tracks that support higher-capacity trains and safety features that the Vegas tunnels lack.
- s1artibartfast 3y ago
  I agree that there are a lot of reasons for the cost differential between the US and Europe, and many reports and papers on the topic. From what I've read, tunnel costs are climbing quickly in Europe. At the end of the day The boring company seems to be able to avoid these high costs using a combination of their technology, simplified goal, and business approach while nobody else has been able to bring costs down for a large tunnels in the US. It would be great if someone could figure out how to bring large Tunnel cost down in the US, but until someone does, smaller tunnels costing a few percent of the cost have a competitive advantage. My understanding is that the problems driving large tunnel construction costs in the US are driven by a shortage of labor expertise, Labor bloat compared to other countries, and institutional inability to manage large projects and avoid scope change.
  - deleted 3y ago
    [deleted]
  - abduhl 3y ago
    >> My understanding is that the problems driving large tunnel construction costs in the US are driven by a shortage of labor expertise, Labor bloat compared to other countries, and institutional inability to manage large projects and avoid scope change. This understanding is not correct. America's tunneling cost problem is driven by labor costs, unions, politics, and third party litigation. The institutional inability to manage large projects is a result of the latter three of these: the people in charge when the contract is signed are often not the people in charge when the job is half completed, and that change in leadership leads to scope changes that should (justifiably) be paid for.
    - s1artibartfast 3y ago
      I dont see a meaningful distinction between the causes you claim and what I said. I agree third party litigation warrants highlighting, but I consider that as part of institutional inability to manage large projects. Likelwise, I see high labor costs and unions as equavalent to lack of skilled labor and bloated labor costs. At the end of the day, we are saying the same thing. Cost of workers is higher, the US uses far more workers, and the US legal and political systems are not condusive to efficient execution.
      - abduhl 3y ago
        Your articulation is not unique to large diameter tunnels, the generic costs you point to are endemic to any diameter tunnel in America and also to any infrastructure project in America that takes place in an urban environment. To say that these things are a "large diameter tunnel" problem is to miss the unique distinctions between TUNNELING costs and INFRASTRUCTURE costs in America. At a high level we agree, but that's not useful for finding a solution to the specific problem of American tunneling costs. For example, the labor shortage impacts all construction in America but tunnels require even more specialized laborers. Unions drive up the cost of all construction in America, but specific unions (like the Sandhogs) have specific provisions in their contracts that drive up the cost even more. Scope changes impact all construction, but scope changes underground cost orders of magnitude more than surface scope changes (add an offramp above ground versus add an offramp underground). Third party litigation impacts all construction, but the nature of tunneling increases the risk of third party litigation because settlement/sinkholes can occur vast distances away from the work.
tobylane 3y ago
Digging a wider tunnel requires a bigger tbm, which adds little to the whole cost. Hs2 put out a paper, though I don’t think it compares sizes. https://assets.publishing.service.gov.uk/government/uploads/ https://assets.publishing.service.gov.uk/government/uploads/... The NYC example is terrible, because the new part of the tunnel is only short and the whole project costs a lot does not mean each mile of the tunnel costs that much. I was first asking why they thought small tunnels are better, is that purely on financial grounds? Low cost, low benefit.
- s1artibartfast 3y ago
  Why is it not appropriate to compare a whole project cost the whole project cost per mile? The New York extension was 7.7 billion for 1.5 MI and the Vegas Loop was 47 million for 1.7 MI. Now you have a project cost per mile and you can evaluate benefit from per mile. Biggest Loop was unquestionably much lower total benefit. Then you can compare benefit per dollar. At 1 200th the price does it provide more or less than 0.5% the value.

beowulfey 3y ago

I guess my thinking was that it works pretty well in London to use smaller tunnels, and I don't immediately understand why larger tunnels are needed. If you're familiar with why tunnels have been trending larger, I'd love to know.