One month after a power outage snarled the morning commute for hundreds of thousands of subway riders, its cause is still disputed.
New York Gov. Andrew Cuomo, who controls the Metropolitan Transportation Authority, blamed the May 9 outage -- as well as a similar power loss two days earlier -- on utility Consolidated Edison Inc.
At the time, a spokesman for Mr. Cuomo demanded that the company "identify the cause and propose a real and improved response plan for the future."
Consolidated Edison, however, has found no evidence that it could have caused the May 9 outage, said Robert Schimmenti, senior vice president of electric operations at the utility.
He added that a transformer failure at a substation on May 7 shouldn't have been sufficient to cause subway disruption on that day either.
Mr. Schimmenti explained that the subway is powered by multiple transformers, and when one transformer fails it causes a power disturbance lasting less than a second, the kind of fluctuation that might cause a lightbulb to flicker. The MTA's equipment "should be designed to handle a disturbance," he said.
Consolidated Edison previously accepted responsibility for a power outage on April 21 at the 7th Avenue and 53rd Street subway station in Manhattan.
MTA spokesman Stephen Morello said that the transit agency continues to "believe that the May 7 and 9 failures were the responsibility of ConEd."
Mr. Cuomo has directed the state's Department of Public Service and the MTA to investigate the April and May outages.
James Allen, a spokesman for Mr. Cuomo, said: "The investigation is ongoing and a full report is expected to be completed early this summer."
The transformer failure on May 7 knocked out signal equipment at DeKalb Avenue in Brooklyn, causing delays for several hours.
The signal system went down again two days later at about 7:30 a.m., affecting the B, D, N, Q and R trains and sending disruption cascading through the system through the rush hour.
The subway's antiquated signal system is a prime cause of delays. Upgrading to a more efficient system will cost billions of dollars and take decades to complete.
In the wake of the disruptions, Brooklyn Borough President Eric Adams asked the city's independent budget office to study the economic cost of the outages to workers, businesses and in the form of lost tax revenue.
A spokesman for the budget office said that study is under way.
Write to Paul Berger at Paul.Berger@wsj.com
(END) Dow Jones Newswires
June 09, 2017 05:44 ET (09:44 GMT)