In a statement released late Sunday morning, the power company said it “will be conducting a diligent and vigorous investigation to determine the root cause of the incident.” Con Ed spokesman Alfonso Quiroz blamed the blackout on a “disruption on the transmission side” of the company’s power grid. Officials initially suspected a manhole fire that affected an underground transformer, but Quiroz said there’s “no evidence of a fire at this point.” The blackout stranded people on subway trains and elevators, and forced the evacuation of Madison Square Garden and cancellation of Broadway shows. It struck on the 42nd anniversary of...