"An unprecedented system breakdown" Sunday night cut power to half the New York City subways, knocking out signaling and communications and stranding hundreds of passengers in darkened tunnels, Gov. Kathy Hochul said Monday. Credit: MTA

A series of failures, including of backup generators and an alert system for MTA workers, resulted in hundreds of stranded subway riders evacuating onto tracks Sunday night, according to a preliminary MTA investigation.

In response to the findings, Gov. Kathy Hochul directed the Metropolitan Transportation Authority to hire a pair of independent engineering firms to conduct a "deep dive" into the failures to prevent similar incidents in the future.

"We are working to find out the full extent of what went wrong, and we will fix it," Hochul said. "New Yorkers deserve absolute confidence in a fully functioning subway system, and I promise to do everything in my power to restore that confidence."

The incident started around 8:25 p.m. on Sunday, when Con Edison experienced the voltage dip that resulted in the MTA's battery-powered backup electrical system being activated. The batteries were only designed to temporarily energize the system until two generators were automatically activated.

But the generators never turned on and the system continued running on the batteries, even after Con Ed restored full power. In addition, an alert system failed that should have informed workers in a control center that the subway was running on batteries — leaving them oblivious to the situation. After 45 minutes, the batteries were drained and the subway system came to a halt.

More than 80 trains — roughly half of those in operation Sunday night — were affected by the outage, including those on the 1, 2, 3, 4, 5, 6, 7 and L subway lines. While most were able to safely evacuate passengers onto station platforms, five trains were stopped in between stations, Hochul said Monday morning during a news conference with MTA officials outside the authority’s Manhattan headquarters.

Emergency personnel led efforts to evacuate passengers on two of those trains, but on two others "riders decided to leave on their own," Hochul said.

"Some people got frustrated, and they went and got off the train themselves, which we really discourage," acting MTA chairman and chief executive officer Janno Lieber said during a Monday morning interview on Fox 5 News.

Hochul said the "dangerous," unauthorized evacuation prolonged the service disruption, as FDNY firefighters had to thoroughly inspect the underground passages to make sure no riders were still walking the tracks. Full service resumed about 1:30 a.m., and there was no impact on the Monday morning rush hour, officials said.

Hochul said the circumstances that caused the incident "never happened before, to our knowledge."

"Let me be clear: Last night was unacceptable. If you were one of those riders relying on safe transport, the system failed you," Hochul said during her first public appearance with MTA officials since being sworn in as governor last week. "We need to know why the system broke down."

Lieber acknowledged that the MTA power system is designed to "fail safe," but it did not operate as designed. He said agency officials will "really dig and make sure we understand what happened here."

In a statement, Con Edison spokesperson Phillip O’Brien said a problem with an underground transmission feeder Sunday night in Long Island City, Queens, resulted in the voltage dip, which lasted just "a fraction of a second." He said the cause of the voltage dip is under investigation.

"We are in contact with the MTA to understand why they lost this communication at their rail center during this voltage disturbance," O’Brien said.

Danny Pearlstein, spokesperson for the Riders Alliance, a transit advocacy group, said the system failures showed how "aging infrastructure and extreme weather are both increasingly getting in our way and scrambling commutes. … Governor Hochul clearly must prioritize the resilience of both our transit system itself and vital supporting infrastructure, including power sources and distribution networks."

With Matthew Chayes

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