5 ms·

Yeah. The major slow projects I can think of in recent years; Second Ave. Subway, East Side Access, Crossrail, etc. all involve deep bore tunneling through som

Yeah. The major slow projects I can think of in recent years; Second Ave. Subway, East Side Access, Crossrail, etc. all involve deep bore tunneling through some of the most densely occupied land on Earth. Utility relocation, minimizing disruption to residents and businesses, etc. are the "hard part" here. If you could just nuke Midtown, East Side Access would have been easy. If you could demolish half of the Upper East Side, build a subway in the crater, and then cover it with new buildings, it would have been ready sooner. But, that's impractical. People are emotionally attached to their homes and neighborhoods. That said, future projects can probably done more cheaply. IBX and QueensLink won't involve much underground work, and the right of way is already clear. The problem is that the benefit isn't clear enough to actually fund the projects and get them started. (That is an even more complicated problem. The MTA is a state body, subway lines entirely within the city are not something people on Long Island and Westchester want to pay for. Maybe there should be some sort of Independent Subway that the city itself pays for ;)

bluGill 5y ago
The low cost leader in subway construction is Spain and they use deep bore tunneling, and they even use larger tunnels than most everyone else (one large tunnel is more expensive than two smaller ones)
pbourke 5y ago
See also Seattle’s SR99 tunnel and Boston’s Big Dig (though the latter is 15 years old now). Tunneling through an existing city, often near water, is just hideously complex and expensive.
- Fomite 5y ago
  I remember when I was in Boston a discussion of how to expand one of the T-lines under Tufts Medical Center without causing vibrational problems for the equipment in the hospital right above. That's a non-trivial engineering challenge.
  - xvector 5y ago
    Have the hospital cease usage of the equipment and relocate appointments for that equipment.
    - Fomite 5y ago
      Gonna be awkward to shut down a major children's hospital in a city for an indeterminate period of time.
      - xvector 5y ago
        Who said you need to shut down usage of the whole hospital? Just usage of those specific machines.

bluGill 5y ago

The low cost leader in subway construction is Spain and they use deep bore tunneling, and they even use larger tunnels than most everyone else (one large tunnel is more expensive than two smaller ones)

pbourke 5y ago

See also Seattle’s SR99 tunnel and Boston’s Big Dig (though the latter is 15 years old now). Tunneling through an existing city, often near water, is just hideously complex and expensive.

Fomite 5y ago
I remember when I was in Boston a discussion of how to expand one of the T-lines under Tufts Medical Center without causing vibrational problems for the equipment in the hospital right above. That's a non-trivial engineering challenge.
- xvector 5y ago
  Have the hospital cease usage of the equipment and relocate appointments for that equipment.
  - Fomite 5y ago
    Gonna be awkward to shut down a major children's hospital in a city for an indeterminate period of time.
    - xvector 5y ago
      Who said you need to shut down usage of the whole hospital? Just usage of those specific machines.