NYC Subway Power Failure

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  • Member since
    May 2019
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NYC Subway Power Failure
Posted by BEAUSABRE on Monday, August 30, 2021 12:40 PM

About half of New York City's subway lines were shut down on Sunday due to a power surge. 

"More than 80 trains and 550 passengers were ultimately affected, including about 300 who got stranded between rail stations in the Bronx and had to be helped out.

The trouble started around 8:30 p.m. when ConEdison reported briefly losing an underground transmission feeder that caused a citywide voltage dip that lasted a fraction of a second for all customers, many of whom reported flickering lights.

At the same time, two power plants and generators went offline, Hochul said.

"It was a momentary outage that did go to the backup system," the governor added. "When it tried to go back to normal, there was a surge, an unprecedented surge that resulted in the subway losing signalization and communication ability and it lost that between its command center and the trains throughout the system."

That's when the drama kicked into high gear for straphangers. The MTA said around 9:30 p.m. there was "extremely limited service" on the 1, 2, 3, 4, 5, 6, 7 and L lines. The power surge affected the ability to make station announcements from the Rail Control Center, and five trains got stuck between stations in the Bronx."

Ex-governor Cuomo has begun his revenge on mayor DeBlassio


  • Member since
    March 2016
  • From: Burbank IL (near Clearing)
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Posted by CSSHEGEWISCH on Monday, August 30, 2021 1:57 PM

Only if the former governor knows how to cause power surges.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
  • Member since
    December 2007
  • From: Georgia USA SW of Atlanta
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Posted by blue streak 1 on Tuesday, August 31, 2021 7:44 AM

Maybe simply explained.

1.  Con Ed had some kind of power fault. BTW power faults do happen more often than many realize.

2.  MTA system switched to battery back for signal system. The batteries may provide power by direct charging so no transfer relay is used. However the fluction caused disconnection from Con Ed, Even a momentary system blackout could zap the signal system ?  Con Ed power supplies power to battery chargers.  Batteries  protect sensitive electronics.

3,  MTA system should have noted Con Ed supply OK. Power to chargers should have restored. Battery chargers should have started but protection system did not supply AC to battery chargers.  System should have gone back to CON ED.

4.  When MTA chargers did not go back to Con Ed  a delay logic should have started  generators  to supply signal system battery chargers .  Maybe transfer relay to switch from commercial to generators failed if generators did start.  that will be determined. 

Pure speculation  ----  Power transfer logic to go back to Con Ed failed. However since the Con Ed power was OK the generators logic did not see need to start.  Appears to be simple programming faulty.  Will some IT person get spanked highly unlikely.

Wonder how often this transfer system is tested and when last test completed ?

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Posted by Overmod on Tuesday, August 31, 2021 9:04 AM

Part of the problem as I understand they're describing it is that the backup protection did not disengage when the line power was restored.

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