3 ms·

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.p

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.