3 ms·

I'm pretty sure there's bedrock in the rest of the world that gets tunneled through. It's not unique to Manhattan.

• lbriner 6y ago
  Sure, bedrock would slow a project down but it wouldn't explain the higher level of labour. If you are moving more slowly, you need less people to keep the supply chain moving, not more. I saw a TV show with a standard Tunnel Boring Machine and it was about 5 men operating it (plus the automated materials feed). Even if they were paid $1M a year, it would still be loads cheaper than these tunnels are costing New York.
• fastball 6y ago
  As far as I'm aware, it actually kinda is (at least compared to other major cities with lots of tunneling). London for instance is built on sedimentary rock (mostly limestone?). The metamorphic bedrock (mostly mica?) Manhattan is on top of is obviously much harder than that.
  • vidanay 6y ago
    If you are referring to the actual Manhattan Schist type of rock, then yes that can have an effect on the cost of tunneling, but that wasn't really what your original post said - you just said "all the bedrock". Switzerland recently completed the Gotthard Base tunnel which is almost all hard rock mining.
    • fastball 6y ago
      I'm no geologist, but I was under the impression that "bedrock" generally refers to this harder type of rock. It is not just a word for any rock that things are built on. Maybe I'm wrong though. I've never heard London referred to as being built on top of bedrock in the same way I've heard it of NYC.
      • vidanay 6y ago
        Bedrock is a generic term for the hard(er) layer of rock underneath the softer stuff. Manhattan has very tough bedrock (schist) London has very soft bedrock (chalk and London Clay) - and it's also deeper