NY Daily News article link
https://www.nydailynews.com/new-york/ny ... story.html
"But Cuomo said a new report will show the current tunnels can be fixed without closing — citing a similar strategy the Metropolitan Transportation Authority used to fix the L train’s Sandy-damaged East River tunnel.
In that project, crews saved time by hanging electrical and communications cables on the tunnel walls and patching up damaged concrete with fiber panels. Similar to the current repair plans for the Hudson River tubes, MTA engineers had previously planned to rip out and replace thousands of feet of concrete to house the cables."
So, if you do not have to rip out the concrete vaults by moving the cabling to the tunnel walls, you will not have to shut the tunnels down for a prolong period of time.
Per Wiki,
https://en.wikipedia.org/wiki/North_River_Tunnels
"The tunnels were built with drilling and blasting techniques and tunneling shields, which were placed at three locations and driven towards each other. The shields proceeded west from Manhattan, east and west from Weehawken, and east from the Bergen portals.
Under the river itself, the tunnels started in rock, using drill and blast, but the strata under the river was pure mud for a considerable depth. As a result, this part was driven under compressed air, using 194-ton shields that met about 3,000 feet (910 m) from the Weehawken and Manhattan portals. The mud was such that the shield was shoved forward without taking any ground; however, it was found that the shield was easier to steer if some mud was taken in through holes at the front, since the mud had the consistency of toothpaste. After the tubes had been excavated, they were lined with 2.5-foot-wide (0.76 m) segmental cast-iron rings, each weighing 22 tons. The segments were bolted together and lined with 22-inch (56 cm) of concrete.
Note, they were lined with concrete - the structural support and watertight barrier is the cast iron segmental rings. 2.5 feet of cast iron is 30 inches thick, the concrete lining is only 22 inches thick.
And the final collaboration of the report by London Bridge Associates, as reported in the wiki link provided.
"In February 2020, Amtrak indicated that it would go forward with the renovation of the North River Tunnels
regardless of the Gateway Program's status."
London Bridge Associates report to the Port Authority, Governor Cuomo, and now Amtrak have officially stated they do not need the new Gateway tunnels to repair the North River tunnels.
Why are so many still making the opposite argument? Are their heads buried in sand ignoring the latest reports and studies?
FYI, London Bridge Associates is a firm with over 500 years of history. They are not some fly by night firm replying yes sir to their political masters.
https://www.lba.london/
Additionally, as an aside, too many folks think the containment building around nuclear reactors are made from just concrete. They are wrong. Per Wiki
https://en.wikipedia.org/wiki/Containment_building
"The containment building itself is typically an airtight
steel structure enclosing the reactor normally sealed off from the outside atmosphere. The steel is either free-standing or attached to the
concrete missile shield. In the United States, the design and thickness of the containment and the missile shield are governed by federal regulations (10 CFR 50.55a), and must be strong enough to withstand the impact of a fully loaded passenger airliner without rupture."
The concrete you see is just a missile shield to protect the steel structure that provides the real containment.
I believe you will find the same is true for the tunnels.
