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realizm

MTA begins GO work on the IND Crosstown Line Greenpoint Tubes for 12 Weeks

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Brace yourselves for major hell of GO's on the (G). The MTA begins repairs on the IND Crosstown line Greenpoint Tubes from damage caused by last years catrostrophic damage from Hurricane Sandy accordinjg to reports from NY1. The repairs will last a total of 12 weeks. Projected date of completion will be in December of this year. The repairs began on July 6th.

 

From the MTA website shows images of the beginning phases of the work to be done on the tunnels from this link: 

 

http://web.mta.info/nyct/service/G_GreenpointTunnelWeekendClosure.htm

 

These are some of the 32 pics that reveals extensive damage to the tunnels posted on the MTA site: 

 

Corrosion to new tie plates and tunnel walls where flood water filled the tunnel almost to the ceiling of the tubes:

 

1_large.jpg

 

3_large.jpg

 

Damage on signal components:

 

11_large.jpg

 

13_large.jpg

 

Duct damage:

 

1_large.jpg

 

5_large.jpg

 

Damage in Electrical Distribution Room (notice water line):

 

15_large.jpg

 

17_large.jpg

 

Electrical cables destroyed by saltwater corrosion causing oxidation of copper wiring inside :

 

8_large.jpg

 

Destroyed communication equipment:

 

7_large.jpg

 

Overview of service changes during this work (mta.info):

 

 

g_shad.jpg Service During Weekend Greenpoint Tube Closures

No g.png trains between Court Sq and Nassau Av

No g.png service at Court Sq, 21 St, and Greenpoint Av stations

Twelve weekends scheduled 

11:45 PM Friday through 5 AM Monday each weekend

July to December 2013[/size] July 5 - 8   12 - 15   19 – 22       August 2 - 5   9 - 12   16 - 19   23 - 26 September 6 - 9   27 - 30         October 4 - 7             December 6 - 9   13 – 16        

While not expected, dates are subject to change.

Visit mta.info for up-to-date information, or call 511

 

Getting Around:

 

Free shuttle buses provide alternate service on two routes

1. Via Manhattan Av between Nassau Av g.png and Court Sq.

2. Via McGuinness Blvd between Lorimer St l.png and Court Sq.

• Transfer between g.png trains and the shuttle buses at Nassau Av station.

• Transfer between l.png trains and the shuttle buses at Lorimer St station.

• Transfer between trains and shuttle buses at Court Sq station.

 

 

Straphangers, good luck.....

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Why are they relaying from Nassau, instead of just using Greenpoint as the terminal?

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Why are they relaying from Nassau, instead of just using Greenpoint as the terminal?

 

Nassau has the crossover, plus Greenpoint pretty much sits right next to the tubes, they would probably need to stage work trains, equipment and personell there. 

 

What I just don't get is why even newly replaced tie blocks are corroding like that? Is it just a layer of salt on everything? If so, couldn't you just spray it down and wash it off? (I mean, I know that's only one facet of the damage)

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Nassau has the crossover, plus Greenpoint pretty much sits right next to the tubes, they would probably need to stage work trains, equipment and personell there. 

 

What I just don't get is why even newly replaced tie blocks are corroding like that? Is it just a layer of salt on everything? If so, couldn't you just spray it down and wash it off? (I mean, I know that's only one facet of the damage)

 

Saltwater corrosion as compared to freshwater corrosion severly and drastically changes the composition of the metal itself, inside out so it's not just a matter of washing off the residue, it will worsen the effect of the damage, in this case the metal ties. If you saw the state of the copper wire you will see what I mean.

 

Scientifically speaking in saltwater corrosion, the chloride ions react with metals to begin a continuous vicious cycle of pitting and severe deterioration in metals particularly in steel (such as galvanized steel) and copper, to the point of no return. Since the ties and rails are not specially coated to resist saltwater corrosion (I'm assuming) along with the irreversible nature of the damage inflicted by saltwater corrosion just described, which is again continuous until the metal ties are completely destroyed the MTA civil engineers assessing  the tunnels deemed the damage as irreversible, therefore there is no way to salvage the steel ties and rails, it must be replaced.

Edited by realizm
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Damn, seeing the damage itself really brings to light the mass endeavor being done to make repairs.

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Saltwater corrosion as compared to freshwater corrosion severly and drastically changes the composition of the metal itself, inside out so it's not just a matter of washing off the residue, it will worsen the effect of the damage, in this case the metal ties. If you saw the state of the copper wire you will see what I mean.

 

Scientifically speaking in saltwater corrosion, the chloride ions react with metals to begin a continuous vicious cycle of pitting and severe deterioration in metals particularly in steel (such as galvanized steel) and copper, to the point of no return. Since the ties and rails are not specially coated to resist saltwater corrosion (I'm assuming) along with the irreversible nature of the damage inflicted by saltwater corrosion just described, which is again continuous until the metal ties are completely destroyed the MTA civil engineers assessing the tunnels deemed the damage as irreversible, therefore there is no way to salvage the steel ties and rails, it must be replaced.

Saltwater corrosion is nasty stuff. (I used to hold a few maritime jobs, I've more experience with it than I'd like)

 

I guess my question was more, the photo caption seems to indicate the steel tie blocks were replaced AFTER the flooding, yet they still corroded badly.

 

Is there enough salt still in the tunnel to cause this (that's what I was asking about rinsing off)?

 

Or is it that saltwater corroded metal will have a parasitic effect on un corroded metal?

 

I'm looking at you Realizm - you seem to know the science on this :-)

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Or is it that saltwater corroded metal will have a parasitic effect on un corroded metal?

 

 

You got it. You answered your own question, that's the reason.

 

As you put it, saltwater corroded metal having a constant and irreversible parasitic effect on otherwise un- corroded metal that lacks specialized coating that is corrosion resistant to sodium chloride suspended in H2O.

 

The ties I guess were never replaced after the storm as I can't recall any weekend GO's on the (G) after they pumped the storm's floodwater out of tunnels. So now the ongoing continuous and constant corrosion is pitting and cracking the metal ties and changing the composition of the metal, like acetone on styrofoam. The adverse chemical reaction cannot be stopped.

 

So the MTA civil engineers know they can no longer wait as the salt water corrosion is still eating up the metal via constant oxidation, they got to replace it, or it will pose a serious danger to passengers and train crews on the cars as derailing accidents might occur. Among other reasons due to saltwater corroision which is also slowly destroying components of the signal, electrical, communication, and sump pumping systems, as well as serious damage to the infrastructure of the tunnels itself. (The iron rings embedded in the reinforced concrete that makes up the tunnel)

Edited by realizm
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