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Klaus Philipsen's avatar

Great overview of construction methods and associated direct and indirect costs. Only very few companies make modern TBMs and usually they are not moved from one city to another but made for a specific job and partly assembled on site. This adds cost. The article doesn’t speak about the cut and cover hole needed to launch or retrieve the TBM. It also doesn’t mention how Musk’s Boring company’s TBM achieves a higher rate of speed than conventional TBM’s, albeit so far only for smaller tunnel sections not useable for subway, LRT or trains.

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Jonathan McMenamin-Balano's avatar

Brian, that was a great post. Both the history and the social effectors that drive design were nuggets of information that certainly backfilled my understanding of the transit and tunneling.

When the MASS dig project opened, you could feel the collective sigh for those driving in the area. Thank you.

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