If you’re interested how some of these things got build in New York in the past I recommend the books of Robert Caro about Robert Moses.

Building new massive infrastructure requires a level of ruthlessness that is not socially acceptable these days.

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timcobb 8 hours ago | parent [-]

Op's example was underground. Moses built above ground, thereby requiring the ruthlessness. Not sure the same ruthlessness would be needed with tunnels.

	▲	jtbetz22 2 hours ago \| parent \| next [-]
		According to Bloomberg[1] construction of the first phase of the second avenue subway cost about 2.5B USD per mile. At that rate, even if you just look at extending the A/C/E from Jamaica to JFK, you're talking about 15B or so USD. And compared to today's [subway\|LIRR] -> airtrain system, you probably only cut about 25% of the travel time (from 60 minutes down to 45 minutes) Compare that to, for example, the Gateway Tunnel, estimated to cost about 16B USD and double the daily commuter capacity from NJ to NYC (including traffic to and from EWR!), and it's hard to justify new infrastructure to make it easier to get to the airport. 1. In NYC Subway, a Case Study in Runaway Transit Construction Costs - Bloomberg https://share.google/SPcN8iRDZG7lNiwt9
	▲	JumpCrisscross 2 hours ago \| parent \| prev \| next [-]
		> Not sure the same ruthlessness would be needed with tunnels Still requires lots of cut and cover due to buried power and water mains being poorly documented. And stations will require razing buildings, as well as gentrifying neighborhoods.
	▲	baxtr 7 hours ago \| parent \| prev [-]
		It’s not only about underground vs evicting people. It’s also in large part about making sure that your project gets the required funding and other (social) projects don’t.