A reader who works across the street from Grand Central wrote in saying "I just went downstairs and saw cops, fire, ConEd, and people said a transformer blew up in the station." It appears Grand Central is fine, however the Met Life Building is on fire! From BNN:

FIRE ON THE 10TH FLOOR OF A METLIFE BLDG.| FIRE ON 10TH FLR TRANSORMER VOLT ROOM OF A 59 STY BRICK BLDG

WIRES BURNING ON THE ROOF LEVEL ON THE 19TH FLOOR OF THE METLIFE BLDG 59 STY WITH DAY CARE ON THE 2ND FLR. LOBBY COMMAND SET UP ON THE 2ND FLR.

CON-ED IS ISOLATING THE CONDITION. SOME UNITS ARE BEING RETURNED. FIRE IS PWH.

Thanks to reader Zoë for the above image.